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[Federal Register Volume 89, Number 242 (Tuesday, December 17, 2024)]
[Proposed Rules]
[Pages 102074-102091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28729]

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R7-ES-2024-0117; FXES1111090FEDR-256-FF09E21000]
RIN 1018-BI15

Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Suckley's Cuckoo Bumble Bee

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the Suckley's cuckoo bumble bee (Bombus suckleyi), an invertebrate 
species from North America, as an endangered species under the 
Endangered Species Act of 1973, as amended (Act). This determination 
also serves as our 12-month finding on a petition to list the Suckley's 
cuckoo bumble bee. After a review of the best available scientific and 
commercial information, we find that listing the species is warranted. 
Accordingly, we propose to list the species as an endangered species 
under the Act. If we finalize this rule as proposed, it would add this 
species to the List of Endangered and Threatened Wildlife and extend 
the Act's protections to the species. Due to the current lack of data 
sufficient to perform required analyses, we conclude that the 
designation of critical habitat for the species is not determinable at 
this time.

DATES: We will accept comments received or postmarked on or before 
February 18, 2025. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59 
p.m. eastern time on the closing date. We must receive requests for a 
public hearing, in writing, at the address shown in FOR FURTHER 
INFORMATION CONTACT by January 31, 2025.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal:
    https://www.regulations.gov. In the Search box, enter FWS-R7-ES-
2024-0117, which is the docket number for this rulemaking. Then, click 
on the Search button. On the resulting page, in the panel on the left 
side of the screen, under the Document Type heading, check the Proposed 
Rule box to locate this document. You may submit a comment by clicking 
on ``Comment.''
    (2) By hard copy: Submit by U.S. mail to: Public Comments 
Processing, Attn: FWS-R7-ES-2024-0117, U.S. Fish and Wildlife Service, 
MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
    We request that you send comments only by the methods described 
above. We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see Information Requested, below, for more information).
    Availability of supporting materials: Supporting materials, such as 
the species status assessment report, are available at https://www.regulations.gov at Docket No. FWS-R7-ES-2024-0117.

FOR FURTHER INFORMATION CONTACT: Mike Daigneault, Acting Field 
Supervisor, Southern Alaska Fish and Wildlife Field Office, 4700 BLM 
Road, Anchorage, AK 99507; telephone 907-271-1467. Individuals in the 
United States who are deaf, deafblind, hard of hearing, or have a 
speech disability may dial 711 (TTY, TDD, or TeleBraille) to access 
telecommunications relay services. Individuals outside the United 
States should use the relay services offered within their country to 
make international calls to the point-of-contact in the United States. 
Please see Docket No. FWS-R7-ES-2024-0117 on https://www.regulations.gov for a document that summarizes this proposed rule.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act, a species warrants 
listing if it meets the definition of an endangered species (in danger 
of extinction throughout all or a significant portion of its range) or 
a threatened species (likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range). If we determine that a species warrants listing, we must list 
the species promptly and designate the species' critical habitat to the 
maximum extent prudent and determinable. We have determined that 
Suckley's cuckoo bumble bee meets the Act's definition of an endangered 
species; therefore, we are proposing to list it as such. Listing a 
species as an endangered or threatened species can be completed only by 
issuing a rule through the Administrative Procedure Act rulemaking 
process (5 U.S.C. 551 et seq.).
    What this document does. We propose to list Suckley's cuckoo bumble 
bee as an endangered species under the Act.
    The basis for our action. Under the Act, we may determine that a 
species is an endangered or a threatened species because of any of five 
factors: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commercial, recreational, scientific, or educational purposes; (C) 
disease or predation; (D) the inadequacy of existing regulatory 
mechanisms; or (E) other natural or manmade factors affecting its 
continued existence. We have determined that Suckley's cuckoo bumble 
bee meets the Act's definition of an endangered species due to threats

[[Page 102075]]

from host species decline, pathogens, pesticides, habitat fragmentation 
and conversion, and climate change.
    Section 4(a)(3) of the Act requires the Secretary of the Interior 
(Secretary), to the maximum extent prudent and determinable, 
concurrently with listing designate critical habitat for the species. 
We have not yet obtained the necessary economic information needed to 
develop a proposed critical habitat designation for the Suckley's 
cuckoo bumble bee, although we are in the process of obtaining this 
information. At this time, we find that designation of critical habitat 
for the Suckley's cuckoo bumble bee is not determinable. When critical 
habitat is not determinable, the Act allows the Service an additional 
year to publish a critical habitat designation (16 U.S.C. 
1533(b)(6)(C)(ii)).

Information Requested

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other governmental agencies, Native 
American Tribes, the scientific community, industry, or any other 
interested parties concerning this proposed rule. We particularly seek 
comments concerning:
    (1) The species' biology, range, and population trends, including:
    (a) Biological or ecological requirements of the species, including 
habitat requirements for feeding, breeding, and sheltering;
    (b) Genetics and taxonomy;
    (c) Historical and current range, including distribution patterns 
and the locations of any additional populations of this species;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for the species, its 
habitat, or both.
    (2) Threats and conservation actions affecting the species, 
including:
    (a) Factors that may be affecting the continued existence of the 
species, which may include habitat modification or destruction, 
overutilization, disease, predation, the inadequacy of existing 
regulatory mechanisms, or other natural or manmade factors;
    (b) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to this species; and
    (c) Existing regulations or conservation actions that may be 
addressing threats to this species.
    (3) Additional information concerning the historical and current 
status of this species.
    (4) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et 
seq.), including information to inform the following factors that the 
regulations identify as reasons why designation of critical habitat may 
be not prudent:
    (a) The species is threatened by taking or other human activity and 
identification of critical habitat can be expected to increase the 
degree of such threat to the species;
    (b) The present or threatened destruction, modification, or 
curtailment of a species' habitat or range is not a threat to the 
species, or threats to the species' habitat stem solely from causes 
that cannot be addressed through management actions resulting from 
consultations under section 7(a)(2) of the Act;
    (c) Areas within the jurisdiction of the United States provide no 
more than negligible conservation value, if any, for a species 
occurring primarily outside the jurisdiction of the United States; or
    (d) No areas meet the definition of critical habitat.
    Please include sufficient information with your submission (such as 
scientific journal articles or other publications) to allow us to 
verify any scientific or commercial information you include.
    Please note that submissions merely stating support for, or 
opposition to, the action under consideration without providing 
supporting information, although noted, do not provide substantial 
information necessary to support a determination. Section 4(b)(1)(A) of 
the Act directs that determinations as to whether any species is an 
endangered or a threatened species must be made solely on the basis of 
the best scientific and commercial data available.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in ADDRESSES. We request that you 
send comments only by the methods described in ADDRESSES.
    If you submit information via https://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted on the website. If your submission is made via a hardcopy 
that includes personal identifying information, you may request at the 
top of your document that we withhold this information from public 
review. However, we cannot guarantee that we will be able to do so. We 
will post all hardcopy submissions on https://www.regulations.gov.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov.
    Our final determination may differ from this proposal because we 
will consider all comments we receive during the comment period as well 
as any information that may become available after this proposal. Based 
on the new information we receive (and, if relevant, any comments on 
that new information), we may conclude that the species is threatened 
instead of endangered, or we may conclude that the species does not 
warrant listing as either an endangered species or a threatened 
species. In our final rule, we will clearly explain our rationale and 
the basis for our final decision, including why we made changes, if 
any, that differ from this proposal.

Public Hearing

    Section 4(b)(5) of the Act provides for a public hearing on this 
proposal, if requested. Requests must be received by the date specified 
in DATES. Such requests must be sent to the address shown in FOR 
FURTHER INFORMATION CONTACT. We will schedule a public hearing on this 
proposal, if requested, and announce the date, time, and place of the 
hearing, as well as how to obtain reasonable accommodations, in the 
Federal Register and local newspapers at least 15 days before the 
hearing. We may hold the public hearing in person or virtually via 
webinar. We will announce any public hearing on our website, in 
addition to the Federal Register. The use of virtual public hearings is 
consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

    We were petitioned on April 23, 2020, by the Center for Biological 
Diversity to list Suckley's cuckoo bumble bee as an endangered species 
and to designate critical habitat for this species under the Act. On 
May 11, 2021, we announced in the Federal Register (86 FR 25833) that 
the petition presented substantial information indicating that this 
species may be warranted for listing; that document also announced the 
initiation of a status review for the species. On April 22, 2022, the 
Center for Biological Diversity filed a complaint that the Service 
failed to meet our statutory deadline to complete a 12-month finding on 
the petition. On September 27, 2022, the Service agreed to submit a 
finding to the Federal Register by December 10, 2024. This action 
constitutes our 12-month finding on the

[[Page 102076]]

2020 petition to list Suckley's cuckoo bumble bee.

Peer Review

    A species status assessment (SSA) team prepared an SSA report for 
Suckley's cuckoo bumble bee. The SSA team was composed of Service 
biologists, in consultation with other species experts. The SSA report 
represents a compilation of the best scientific and commercial data 
available concerning the status of the species, including the impacts 
of past, present, and future factors (both negative and beneficial) 
affecting the species.
    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 
2016, memorandum updating and clarifying the role of peer review in 
listing and recovery actions under the Act (https://www.fws.gov/sites/default/files/documents/peer-review-policy-directors-memo-2016-08-22.pdf), we solicited independent scientific review of the information 
contained in the Suckley's cuckoo bumble bee SSA report. We sent the 
SSA report to nine independent peer reviewers and received seven 
responses. Results of this structured peer review process can be found 
at https://www.regulations.gov. In preparing this proposed rule, we 
incorporated the results of these reviews, as appropriate, into the SSA 
report, which is the foundation for this proposed rule.

Summary of Peer Reviewer Comments

    As discussed in Peer Review above, we received comments from seven 
peer reviewers on the draft SSA report. We reviewed all comments we 
received from the peer reviewers for substantive issues and new 
information regarding the contents of the SSA report. The peer 
reviewers generally concurred with our methods and conclusions, and 
provided additional information, clarifications, and suggestions. These 
suggestions included providing more detailed explanations of 
assumptions and uncertainties, more discussion of model strengths and 
limitations, and clarifications in terminology and discussions of 
genetic diversity; they also made other minor editorial suggestions. 
Otherwise, no substantive changes to our analysis and conclusions 
within the SSA report were deemed necessary, and peer reviewer comments 
are addressed in version 1.0 of the SSA report (Service 2024, entire).

I. Proposed Listing Determination

Background

    A thorough review of the taxonomy, life history, and ecology of 
Suckley's cuckoo bumble bee is presented in the SSA report (version 
1.0; Service 2024, pp. 11-28). Suckley's cuckoo bumble bee is an 
obligate social parasite (it depends on social hosts for survival and 
raising young) in the subgenus Psithyrus. Bumble bees in this subgenus 
lack a mechanism to carry pollen and are unable to produce worker bees, 
so they are entirely dependent on social bumble bee hosts to collect 
pollen to rear their young (Lhomme and Hines 2019, p. 126). Since 
Suckley's cuckoo bumble bees are entirely dependent on host bumble bee 
colonies, host colony availability is critical for the species' 
survival and overall viability. Cuckoo bumble bees are generally 
observed in low abundance at the margins of a host species' range, and 
cuckoo bumble bee distributions are less than that of the host species 
(Antonovics and Edwards 2011, p. 1003).
    Cuckoo bumble bee females emerge from hibernation in the spring and 
usurp the nest of a suitable host colony, where host workers care for 
their young. Suckley's cuckoo bumble bee is described as a semi-
specialist parasite (Lhomme and Hines 2019, p. 129) and is confirmed to 
usurp nests of western bumble bees (Bombus occidentalis) and Nevada 
bumble bees (B. nevadensis), with other potential hosts in subgenus 
Bombus throughout the extent of its range (see Host Species Decline, 
below).
    The species has a broad historical distribution across North 
America and it has been found in various habitat types including 
prairies, grasslands, meadows, urban and agricultural areas, and 
woodlands from 2 to 3,200 meters (6 to 10,500 feet) in elevation 
(Williams et al. 2014, pp. 164-165; Committee on the Status of 
Endangered Wildlife in Canada (COSEWIC) 2019, p. 26; Martin et al. 
2023, p. 22; Montana Natural Heritage Program 2023, entire; Service 
2024, pp. 17-19). The analytical units and occurrences of Suckley's 
cuckoo bumble bee are shown below in figure 1.

[[Page 102077]]

[GRAPHIC] [TIFF OMITTED] TP17DE24.075

[[Page 102078]]

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and the implementing 
regulations in title 50 of the Code of Federal Regulations set forth 
the procedures for determining whether a species is an endangered 
species or a threatened species, issuing protective regulations for 
threatened species, and designating critical habitat for endangered and 
threatened species.
    The Act defines an ``endangered species'' as a species that is in 
danger of extinction throughout all or a significant portion of its 
range, and a ``threatened species'' as a species that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether any species is an endangered species or a threatened 
species because of any of the following factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the species' expected response and 
the effects of the threats--in light of those actions and conditions 
that will ameliorate the threats--on an individual, population, and 
species level. We evaluate each threat and its expected effects on the 
species, then analyze the cumulative effect of all of the threats on 
the species as a whole. We also consider the cumulative effect of the 
threats in light of those actions and conditions that will have 
positive effects on the species, such as any existing regulatory 
mechanisms or conservation efforts. The Secretary determines whether 
the species meets the definition of an ``endangered species'' or a 
``threatened species'' only after conducting this cumulative analysis 
and describing the expected effect on the species.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis, which is 
further described in the 2009 Memorandum Opinion on the foreseeable 
future from the Department of the Interior, Office of the Solicitor (M-
37021, January 16, 2009; ``M-Opinion,'' available online at https://www.doi.gov/sites/doi.opengov.ibmcloud.com/files/uploads/M-37021.pdf). 
The foreseeable future extends as far into the future as the U.S. Fish 
and Wildlife Service and National Marine Fisheries Service (hereafter, 
the Services) can make reasonably reliable predictions about the 
threats to the species and the species' responses to those threats. We 
need not identify the foreseeable future in terms of a specific period 
of time. We will describe the foreseeable future on a case-by-case 
basis, using the best available data and taking into account 
considerations such as the species' life-history characteristics, 
threat projection timeframes, and environmental variability. In other 
words, the foreseeable future is the period of time over which we can 
make reasonably reliable predictions. ``Reliable'' does not mean 
``certain''; it means sufficient to provide a reasonable degree of 
confidence in the prediction, in light of the conservation purposes of 
the Act.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data regarding 
the status of the species, including an assessment of the potential 
threats to the species. The SSA report does not represent our decision 
on whether the species should be proposed for listing as an endangered 
or threatened species under the Act. However, it does provide the 
scientific basis that informs our regulatory decisions, which involve 
the further application of standards within the Act and its 
implementing regulations and policies.
    To assess the viability of Suckley's cuckoo bumble bee, we used the 
three conservation biology principles of resiliency, redundancy, and 
representation (Shaffer and Stein 2000, pp. 306-310). Briefly, 
resiliency is the ability of the species to withstand environmental and 
demographic stochasticity (for example, wet or dry, warm or cold 
years); redundancy is the ability of the species to withstand 
catastrophic events (for example, droughts, large pollution events); 
and representation is the ability of the species to adapt to both near-
term and long-term changes in its physical and biological environment 
(for example, climate conditions, pathogens). In general, species 
viability will increase with increases in resiliency, redundancy, and 
representation (Smith et al. 2018, p. 306). Using these principles, we 
identified the species' ecological requirements for survival and 
reproduction at the individual, population, and species levels, and 
described the beneficial and risk factors influencing the species' 
viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical 
and current condition of the species' demographics and habitat 
characteristics, including an explanation of how the species arrived at 
its current condition. The final stage of the SSA involved making 
predictions about the species' responses to positive and negative 
environmental and anthropogenic influences. Throughout all of these 
stages, we used the best available information to characterize 
viability as the ability of a species to sustain populations in the 
wild over time, which we then used to inform our regulatory decision.
    The following is a summary of the key results and conclusions from 
the SSA report; the full SSA report can be found at Docket No. FWS-R7-
ES-2024-0117 on https://www.regulations.gov.

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of the 
species and its resources, and the threats that influence the species' 
current and future

[[Page 102079]]

condition, in order to assess the species' overall viability and the 
risks to that viability.

Species Needs

    There have been few studies focused specifically on understanding 
Suckley's cuckoo bumble bee biology and needs. Thus, we relied on 
information available for cuckoo bumble bees (subgenus Psithyrus) or 
bumble bees (genus Bombus) where appropriate.
Host Species
    Suckley's cuckoo bumble bees cannot successfully reproduce without 
the availability of suitable host bumble bee colonies. Female cuckoo 
bumble bees invade host bumble bee nests where they will often 
eliminate the host queen, destroy host eggs, and eject host larvae from 
the nest. This may be driven by the need to create space for parasitic 
eggs and/or to increase the incubation effort of host workers towards 
parasitic eggs. Cuckoo bumble bees lack a mechanism to carry pollen and 
are unable to produce worker bees, and thus depend on social bee hosts 
to collect the pollen on which they rear their young (Lhomme and Hines 
2019, p. 126). Thus, survival of Suckley's cuckoo bumble bees is 
dependent upon the survival and health of the host colony.
Food Resources
    Cuckoo bumble bees require diverse native floral resources (pollen 
and nectar) for nutrition. Limited information exists regarding key 
forage plants for cuckoo bumble bees (Dozier et al. 2023, p. 643), but 
abundant spring floral resources are important to cuckoo bumble bee 
females for ovary development (Lhomme and Hines 2019, p. 132) and 
abundant fall floral resources are important to the fitness of the 
colony (Hatfield and LeBuhn 2007, pp. 156-157), since this is when new 
gynes (the primary reproductive females) and drones (male bees that are 
solely responsible for reproduction) are produced (Goulson 2010a, pp. 
6-8). In addition, fall floral resources are important for females who 
must survive an overwintering diapause (a period of suspended 
development) without foraging (Beekman et al. 1998, p. 207; Ogilvie and 
CaraDonna 2022, p. 2419). Because cuckoo bumble bees are dependent on 
host workers to raise their offspring, females tend to emerge from 
hibernation later than their hosts to feed on nectar and pollen in 
preparation for laying eggs (Lhomme and Hines 2019, p. 132). While 
specific requirements for overwintering sites are unknown, Suckley's 
cuckoo bumble bee females likely overwinter in and under mulch or other 
decomposing vegetation that is separated from nesting habitat (COSEWIC 
2019, p. 27; Liczner and Colla 2019, p. 793; Martin et al. 2023, p. 
25).
Habitat and Population Connectivity
    Dispersal of bees is necessary to find unrelated mates and is aided 
by the proximity of other usurped colonies and the presence of suitable 
dispersal corridors. Bumble bee reproductive individuals (drones and 
gynes) can disperse up to 10.0 kilometer (km) (6.2 mile (mi)) (Darvill 
et al. 2006, p. 606; Jha and Kremen 2013, p. 2490; Lepais et al. 2010, 
p. 287). Dispersal distance can vary widely across species, and it has 
not yet been described for Suckley's cuckoo bumble bees. The 
indiscriminate cuckoo bumble bee (B. insularis) was found to disperse 
up to 7.0 km (4.3 mi) which is comparable to research on other Bombus 
species (Koch et al. 2021, p. 5). Connectivity is a constraint for 
cuckoo bumble bees because they live in small, fragmented populations 
as a result of their dependence on host bumble bee colonies (Suhonen et 
al. 2016, p. 529). Population connectivity is important for Suckley's 
cuckoo bumble bee's viability as it increases the likelihood of genetic 
diversity, which promotes successful reproduction. Bumble bees are 
prone to producing unviable sterile males when genetic diversity 
between mating pairs is low (Zayed 2009, p. 239). Sterile males are 
unable to contribute to the following year's cohort, which can have 
negative impacts to the population and overall species viability.
    Dispersal of bees to find unrelated mates is aided by the proximity 
of other usurped colonies. Consequently, the sharp historical decrease 
in the prevalence of both Suckley's cuckoo bumble bee, and many of its 
confirmed and potential host species (see Historical, Current, and 
Near-term Condition of Suckley's Cuckoo Bumble Bee, below), has likely 
reduced population connectivity relative to historical conditions. 
Reduced gene flow may have consequences on the genetic diversity of 
Suckley's cuckoo bumble bee, because small populations can experience 
stronger genetic drift (Zayed 2009, p. 246). This is important because 
high genetic diversity reduces prevalence of some pathogens (Parsche 
and Lattorff 2018, p. 900), and the risk of matched mating, which 
produces sterile males that do not contribute to population growth 
(Zayed 2009, p. 239).
Thermal Suitability
    Bumble bees require temperatures to be within a suitable range 
throughout their lifecycle; however, this temperature range appears to 
be highly variable both across and within bumble bee species (Service 
2024, pp. 20-22). Based on occupancy modeling results for Suckely's 
cuckoo bumble bee, occupancy is greatest when the average maximum 
temperature is near 20 Celsius ([deg]C) (68 Fahrenheit ([deg]F)) and 
declines when temperatures are lower and higher than the average 
maximum temperature (Service 2024, p. 64). In general, as bumble bees 
approach the lower end of their thermal limits, they become lethargic 
(Oyen et al. 2016, p. 53). Additionally, extreme cold can affect 
foraging behavior; exposure to cold (approximately 4[deg]C (39[deg]F) 
for 5 minutes) reduced bumble bee foraging for days after exposure 
(Wilson et al. 2006, p. 171). The upper end of some bumble bee thermal 
limits, where loss of muscle control occurs, ranged from approximately 
38 to 53[deg]C (100-129[deg]F) (Hamblin et al. 2017, p. supplemental 
dataset; Oyen et al. 2016, p. 54; Oyen and Dillon 2018, p. 4). Compared 
to other bee species, bumble bees may be particularly sensitive to 
increases in temperature (Hamblin et al. 2017, p. 3). Further, bumble 
bee abundance was observed to decrease following heat waves in Europe 
(Rasmont and Iserbyt, 2012, p. 276).
    Nest temperatures are important to the maintenance and growth of 
the colony (Heinrich 1979, p. 68; Vogt 1986, p. 64). Temperatures in 
underground bumble bee nests fluctuate less than in the surrounding 
environment, maintaining around 30[deg]C (86[deg]F) (Vogt, 1986, p. 61; 
Goulson, 2010a, p. 20; Heinrich 1979, p. 66), due to insulating 
qualities and colony behavior. Nest temperatures outside of ideal 
thermal ranges can slow larvae development and colony growth (Heinrich 
1979, p. 68; Vanderplanck et al. 2019, p. 3; Vogt 1986, p. 64). The 
brood is most susceptible to cold temperatures earlier in the season 
when ambient temperatures are low, and the colony is small.
    In summary, Suckley's cuckoo bumble bee must have availability of 
suitable host colonies, sufficient food resources, connectivity, and 
thermal suitability to support viability. Highly resilient populations 
consist of many genetically diverse individuals that have all their 
basic resource needs met (host colony availability, floral resource 
abundance and diversity, overwintering site availability, population 
connectivity, and thermal suitability). This translates into a diverse 
collection of individuals on the landscape with high survival and 
reproduction success, which ultimately results in population

[[Page 102080]]

growth and larger populations. Survival and reproduction of Suckley's 
cuckoo bumble bees depend on the survival and health of the host 
colony. Host colony workers are paramount to the growth and survival of 
new generations of Suckley's cuckoo bumble bees because they forage and 
care for the brood of parasite larva.
    Redundancy for Suckley's cuckoo bumble bee is described as having 
multiple, healthy populations widely distributed across the breadth of 
adaptive diversity relative to the spatial occurrence of catastrophic 
events (e.g., pathogen outbreak, wildfire, or drought events). In 
addition to guarding against a single or series of catastrophic 
event(s) extirpating all populations of Suckley's cuckoo bumble bee, 
redundancy is important to protect against losing irreplaceable sources 
of adaptive diversity. Having multiple populations distributed across 
the range of the species will help preserve the breadth of adaptive 
diversity and, hence, the evolutionary flexibility of the species.
    The adaptive capacity, as it relates to representation, of 
Suckley's cuckoo bumble bee is a function of the amount and spatial 
distribution of genetic and phenotypic diversity. Based on genetic 
studies of other bumble bee species with similar ecologies, and given 
the potential dispersal capability, Suckley's cuckoo bumble bee may not 
exhibit much genetic differentiation across its broad range. Genetic 
variation can be negatively affected by genetic drift; small 
populations experience stronger drift (Zayed 2009, p. 246). Thus, 
preserving the genetic diversity of Suckley's cuckoo bumble bee may 
require maintaining relatively large populations and connectivity among 
them.

Threats

Host Species Decline
    Cuckoo bumble bees have higher threat indices (higher extinction 
vulnerability) than host species because they are entirely dependent on 
host colonies for reproduction (Suhonen et al. 2015, pp. 238-239). The 
presence of parasitic bees depends on the presence of their hosts; any 
stressor effects on the host will be reflected in the status of the 
parasite (Sheffield et al. 2013, p. 508). Because cuckoo bumble bees 
depend on host species, there is a co-extinction risk for host and 
parasite species (Suhonen et al. 2015, p. 238). Thus, signs that host 
species are declining are of major concern to the viability of 
Suckley's cuckoo bumble bee. The effect of all the stressors impacting 
Suckley's cuckoo bumble bee are compounded through the additional 
effects of these stressors on host species availability (Service 2024, 
p. 33).
    Suckley's cuckoo bumble bee is part of a group in the subgenus 
Psithyrus which primarily parasitizes bumble bees in the subgenus 
Bombus (Lhomme and Hines 2019, p. 129). Bumble bee nests are rare to 
encounter at a baseline, and usurped nests are even rarer to encounter, 
making observations supporting host choice limited (Lhomme and Hines 
2019, pp. 132-133). Additionally, cuckoo bumble bee females may shelter 
in nests they do not usurp, leading to inconclusive observations.
    Given these challenges, our current understanding is that Suckley's 
cuckoo bumble bee has two confirmed hosts and numerous potential hosts. 
The western bumble bee is the most widely known host of Suckley's 
cuckoo bumble bee (Hobbs 1968, p. 164; Williams et al. 2014, p. 165; 
Lhomme and Hines 2019, p. 128). The western bumble bee occurs 
throughout the core of Suckley's cuckoo bumble bee's range in western 
North America. There are also three records of Suckley's cuckoo bumble 
bee nesting successfully (i.e., rearing young) in Nevada bumble bee 
nests (Hobbs 1965, p. 127).
    Aside from these two confirmed hosts, there are numerous potential 
hosts (Service 2024, pp. 35-37) including yellow-banded bumble bee (B. 
terricola), red-belted bumble bee (B. rufocinctus), yellow bumble bee 
(B. fervidus), and white-shouldered bumble bee (B. appositus) (Hobbs 
1968, pp. 157, 164; Williams et al. 2014, p. 165). Suckley's cuckoo 
bumble bees are also observed in locations beyond the range of these 
confirmed and potential hosts (based on nest observations). Because of 
this, it is reasonable to assume there are additional hosts not yet 
confirmed through observations. The following additional potential 
hosts have been identified for Suckley's cuckoo bumble bee: rusty 
patched bumble bee (B. affinis), McKay's bumble bee (B. mckayi), and 
cryptic bumble bee (B. cryptarum) (COSEWIC 2019, p. 17; Service 2024, 
pp. 5-6).
    Over the past century, many species parasitized by Suckley's cuckoo 
bumble bee have documented declines (Hatfield et al. 2014, p. 46; 
Hatfield et al. 2015, p. 4; COSEWIC 2019, p. vi). Trends observed 
across North America suggest subgenus Bombus species are experiencing 
widespread declines (Giles and Ascher 2006, pp. 217-218; Colla and 
Packer 2008, p. 1387; Schweitzer et al. 2012, p. 7; Janousek et al. 
2023, p. 2). For the SSA report, we updated a multi-species occupancy 
model (Jackson et al. 2022, entire) to evaluate host species declines 
for two confirmed hosts (western bumble bee and Nevada bumble bee), and 
four potential hosts in the subgenus Bombus (rusty patched bumble bee, 
McKay's bumble bee, yellow-banded bumble bee, and cryptic bumble bee). 
The western bumble bee, McKay's bumble bee, rusty patched bumble bee, 
and yellow-banded bumble bee all exhibited statistically significant 
temporal declines in occupancy rangewide (Service 2024, pp. 69-70). 
Since Suckley's cuckoo bumble bee is dependent on host species for 
survival, declines in host species abundance is having significant 
impacts to Suckley's cuckoo bumble bee viability.
Managed Bees
    Generally, the term ``managed bees'' describes hives or colonies of 
bees that are used commercially to provide pollination services for a 
wide variety of crops over the growing season. Some hives or colonies 
are moved within and between States multiple times throughout a single 
growing season. Within the range of Suckley's cuckoo bumble bee, 
managed bees are used for a wide variety of crops including, but not 
limited to, alfalfa, almonds, apples, avocado, canola, cherries, 
sunflowers, squash, melon, berries, cucumbers, and clover (Bond et al. 
2014, entire). The use of managed bees is expanding in some portions of 
the range of Suckley's cuckoo bumble bee, including western Canada 
(COSEWIC 2019, p. 49). Managed bees also include hobby or backyard bee 
keeping, as well as small-scale greenhouse operations. Managed bees 
include many different species of bees, such as the introduced European 
honey bee (Apis mellifera) and several species of native North American 
bumble bees, including common eastern bumble bee (B. impatiens), an 
eastern species that has recently been moved into the range of 
Suckley's cuckoo bumble bee for commercial pollination services 
(Palmier and Sheffield 2019, p. 9).
    Managed bees are a threat to Suckley's cuckoo bumble bee in two 
primary contexts--as a pathway for pathogen introduction and spread, 
and competition for resources (Thomson 2004, p. 467; Winter et al. 
2006, entire; Goulson et al. 2008, p. 193; Goulson 2010b, p. 10; 
F[uuml]rst et al. 2014, p. 365; Goulson et al. 2015, p. 11). For 
example, wild bumble bees located more closely to managed honey bee 
colonies had significantly higher disease rates than wild bumble bees 
located farther away (Alger et al. 2019, p. 5). Similarly, infection 
rates for several bumble bee pathogens were higher in multiple

[[Page 102081]]

Bombus species near commercial greenhouses where managed bees were used 
than in areas located far away from commercial greenhouses (Colla et 
al. 2006, pp. 462-464).
    While individual Suckley's cuckoo bumble bees need floral resources 
for nectar and pollen, competition for resources likely more directly 
affects the hosts for Suckley's cuckoo bumble bees, such as western 
bumble bees, whose colonies may have hundreds of foraging workers. As a 
result of competition, populations of wild Bombus species have been 
shown to decrease with an increase in honey bee density (Thomson 2016, 
p. 1251). In particular, western bumble bee colonies that were found 
near higher densities of managed honey bees had reduced reproductive 
success (Thomson 2004, p. 464).
Pathogens
    Bumble bees are susceptible to a variety of pathogens including 
fungal pathogens, parasites, tracheal mites, viruses, and nematodes. 
Many of these pathogens are widespread and cause lethal and sublethal 
effects for Bombus species. We provide a brief summary below of some 
pathogens that are known to affect Suckley's cuckoo bumble bee, its 
hosts, or both. Please see the SSA report for a detailed review of all 
pathogens affecting Suckley's cuckoo bumble bees (Service 2024, pp. 38-
34).
    The fungal pathogens Vairimorpha bombi (formerly Nosema bombi; 
Tokarev et al. 2020, p. 11) and V. ceranae (formerly Nosema ceranae; 
Tokarev et al. 2020, p. 11) which are caused by microsporidian 
parasites, can have lethal and sublethal effects on bumble bees, 
including disabled wings and impacts to reproduction (Otti and Schmid-
Hempel 2007, p. 122), suppressed immune response, and increased 
mortality (Graystock et al. 2013, pp. 116-117; Graystock et al. 2014, 
p. 9; Rotheray et al. 2017, p. 294; Service 2018, p. 52). Vairimopha 
bombi has been documented in Suckley's cuckoo bumble bee, one confirmed 
host species (western bumble bee), and four suspected host species 
(rusty patched bumble bee, yellow bumble bee, red-belted bumble bee, 
yellow-banded bumble bee) (Kissinger et al. 2011, p. 222; Cordes et al. 
2012, p. 212), and it is classified as an emerging infectious disease 
(Sachman-Ruiz et al. 2015, p. 2044; Wilfert et al. 2016, pp. 595-596).
    Many protozoan parasites have been documented in bumble bees in 
North America and can negatively affect populations by reducing colony 
founding success, lowering colony fitness and growth, causing delayed 
reproduction and inadequate fat reserves in hibernating queens, and 
causing adult mortality (Shykoff and Schmid-Hempel 1991, p. 242; 
Schmid-Hempel 2001, pp. 148, 150-154; Brown et al. 2003, pp. 995-1000). 
In particular, Apicystis bombi is a protozoan parasite classified as an 
emerging infectious disease (Sachman-Ruiz et al. 2015, p. 2044; Wilfert 
et al. 2016, pp. 595-596). This disease has not been documented in 
Suckley's cuckoo bumble bee, but it has been documented in Nevada 
bumble bee, one of two confirmed host species (Maxfield-Taylor et al. 
2011, p. 4).
    Several honey bee viruses (e.g., deformed wing virus, black queen 
cell virus, sacbrood virus, Kashmire bee virus, Israeli acute paralysis 
virus, and acute bee paralysis virus) are also known to infect bumble 
bees (Singh et al. 2010, p. 8; Robson-Hyska 2017, pp. 124-125; Tehel et 
al. 2022, p. 4). These viruses have not been documented in Suckley's 
cuckoo bumble bee, but they have been documented in several of its 
potential hosts, including red-belted bumble bee, yellow bumble bee, 
and yellow-banded bumble bee (Robson-Hyska 2017, pp. 63-65, 124-125).
    Parasitic nematodes, such as Sphaerularia bombi, can result in 
multiple negative effects to bumble bee queens, including changes in 
gene expression affecting energy usage, translation, and circadian 
rhythm (Colgan et al. 2020, p. 170), and in endocrine gland function 
involved in growth and development in the larva and pupa (Maxfield-
Taylor et al. 2011, p. 134). Sphaerularia bombi has not been documented 
in Suckley's cuckoo bumble bee, but it has been documented in western 
bumble bee (Poinar 1974, p. 305).
    In summary, bumble bees are susceptible to a variety of pathogens 
and parasites, many of which are widespread and cause lethal and 
sublethal effects for Bombus species. Although we lack information on 
pathogen studies specific to Suckley's cuckoo bumble bee (Dozier et al. 
2023, p. 642), we know many of these pathogens and parasites have 
negative impacts to host species.
Pesticides
    A variety of pesticides are widely used in agricultural, urban, and 
natural environments, including herbicides, insecticides, fungicides, 
miticides, rodenticides, and adjuvants. The pesticides with greatest 
effects on bumble bees are herbicides and insecticides (particularly, 
neonicotinoids, see below for more detail). Herbicide use can cause 
changes in vegetation and the loss or reduction of flowers needed to 
provide consistent sources of pollen, nectar, and nesting material 
(Johansen 1977, p. 188; Kearns et al. 1998, pp. 91-92; Kearns and 
Inouye 1997, p. 302; Plowright et al. 1978, p. 1145; Smallidge and 
Leopold 1997, p. 264). Insecticides are specifically designed to 
directly kill insects, which includes bumble bees, and herbicides 
reduce available floral resources, thus indirectly affecting bumble 
bees. For a full review of pesticides and the effects on bumble bees, 
please see the SSA report (Service 2024, pp. 42-44).
    Neonicotinoids are a class of insecticides that are used in a wide 
variety of agricultural applications, including common use as seed 
coatings in corn, wheat, soybeans, and cotton (Alford and Krupke, 2017, 
p. 1) and have been strongly implicated in the decline of several 
Bombus species (Colla and Packer 2008, p. 10; Goulson 2013, pp. 7-8; 
Pisa et al. 2015, p. 69). Neonicotinoids are currently used throughout 
the range of Suckley's cuckoo bumble bee in North America. 
Neonicotinoids kill insects by interfering with the receptors of their 
nervous systems, causing overstimulation, paralysis, and death 
(Buszewski et al. 2019, p. 34728). Sublethal effects of neonicotinoids 
to bumble bees can include impairments to reproduction (Whitehorn et 
al. 2012, pp. 351-352; Baron et al. 2017, p. 4; Raine 2018, p. 40; Wu-
Smart and Spivak 2018, pp. 4-5). Suckley's cuckoo bumble bee have been 
observed in and around regions of agricultural production, including 
those involved in the production of crops commonly treated with 
neonicotinoids.
Habitat Conversion and Fragmentation
    The conversion of natural habitat to agricultural and urban areas 
is the primary cause of bumble bee habitat loss (Goulson et al. 2015, 
p. 2). Suckley's cuckoo bumble bee is associated with a wide variety of 
habitats including prairies, grasslands, meadows, and woodlands as well 
as urban and agricultural areas (COSEWIC 2019, p. 26; Martin et al. 
2023, p. 22; Montana Natural Heritage Program 2023, entire). Habitat 
conversion and fragmentation reduce the amount and/or accessibility of 
suitable host nests and foraging and overwintering habitat. Habitat 
conversion and fragmentation also reduce the connectivity required for 
healthy populations to expand in response to environmental or 
demographic changes and to maintain genetic diversity. High populations 
of bumble bee species are associated with diverse floral resources, 
particularly when surrounded by a complexity of

[[Page 102082]]

natural habitats across the landscape (Hines and Hendrix 2005, pp. 
1481-1483; Hatfield and LeBuhn 2007, pp. 154-157). Due to their 
foraging, nesting and overwintering requirements, bumble bees are 
sensitive to the negative effects of habitat fragmentation (Kearns and 
Inouye 1997, p. 298).
    Habitat loss is commonly cited as a long-term contributor to bee 
declines through the 20th century, and it may continue to contribute to 
current declines, at least for some species (Goulson et al. 2008, pp. 
191-198; Brown and Paxton 2009, pp. 411-412; Goulson et al. 2015, p. 
2). As generalist foragers, Suckley's cuckoo bumble bee and its 
confirmed host species may not be as severely affected by historical 
and ongoing habitat loss compared to habitat specialists. However, 
habitat loss or degradation reduces bee diversity and abundance (Potts 
et al. 2010, pp. 348-349), and small, isolated patches of habitat may 
not be sufficient to support healthy bee populations ([Ouml]ckinger and 
Smith 2006, pp. 55-56; Hatfield and LeBuhn 2007, pp. 154-156).
    Habitat conversion leads to the reduction of abundant and diverse 
floral resources, which can lead to a lack of sufficient nutritional 
resources; can reduce colony growth, health, and reproduction; and can 
negatively influence long-term bee populations (Vaudo et al. 2015, p. 
4040). Food shortfalls because of habitat loss can induce longer larval 
development, can produce smaller and fewer individuals, and can cause 
an early shift to male production (Beekman and van Stratum 1998, 
entire; Sutcliffe and Plowright 1990, pp. 1056-1057). Larval and colony 
growth can be significantly affected by pollen type (plant species), 
pollen diversity, and the varying nutritional quality and quantity. 
Nutritional stress caused by habitat loss can affect learning and 
memory that can lead to reduced foraging efficiency, increased 
competition, and overall decline in colony fitness (Townsend-Mehler and 
Dyer 2011, pp. 275-286; Colla 2016, p. 413).
    Monoculture farming is another factor that impacts plant community 
changes and thus reduces nesting opportunities for host colonies 
(Kearns and Inouye 1997, p. 298). Agricultural manipulation and changes 
across various landscape types likely impacted the availability of host 
nest sites in North America in the 20th century due to habitat 
degradation, modification, conversion, and loss (Goulson 2003, p. 142). 
These are important changes because diet breadth and coexistence in 
bumble bees can become limited due to habitat loss (Goulson et al. 
2008, pp. 193-200) and coexistence is important for parasitic species 
such as the Suckley's cuckoo bumble bee that rely on host colonies to 
raise their young. Decreases in foraging habitat increases competition 
among bumble bee species, because there is overlap in resources that 
these species use (Goulson et al. 2008, p. 196).
    While habitat conversion and fragmentation are well documented 
throughout the range of Suckley's cuckoo bumble bee, limited recent 
observations show Suckley's cuckoo bumble bee, western bumble bee, and 
rusty patched bumble bee populations do occur in urban and agricultural 
settings. However, these areas may not represent high-quality habitat 
with diverse native floral resources, and records of species in these 
habitats may represent refugia from the primary threats in these areas 
(i.e., application of pesticides in agricultural settings) (Everett 
2023, pers. comm.).
Climate Change
    Changes in ambient temperatures and heatwaves--Global annual 
surface temperatures have risen an average of 0.09 [deg]C (0.17 
([deg]F)) each decade from 1901 to 2020 (U.S. Environmental Protection 
Agency (EPA) 2021, n.p.). Temperature increases in the contiguous 
United States since the late 1970s have surpassed the global rates for 
that period, increasing from 0.17 [deg]C to 0.30 [deg]C (0.31 [deg]F to 
0.54 [deg]F) each decade. The northern and western parts of the United 
States have experienced the greatest temperature increases (EPA 2021, 
n.p.), representing much of the range of Suckley's cuckoo bumble bee. 
Suckley's cuckoo bumble bee has been observed at latitudes up to 68.9 
degrees North, within the Arctic Circle. Based on the most recent 
climate models, temperatures in the Arctic have increased at three 
times the global rate, and are expected to continue to increase at a 
higher rate than the global average, with surface temperatures 
exceeding 6 [deg]C (42.9 [deg]F) above preindustrial times by the end 
of the 21st century (Ma et al. 2022, pp. 1, 7; Hayhoe et al. 2018, pp. 
91-92). Climate change is contracting temperate, arctic, and alpine 
zones (Staten et al. 2018, p. 770) in which bumble bees are distributed 
and to which they are adapted (Goulson 2010a, p. 2).
    In addition to increasing average temperatures, heatwaves in the 
United States have become more frequent, more intense, and longer in 
duration (EPA 2021, n.p.). Rising ambient temperatures and heatwaves 
can negatively affect bumble bee individuals and colonies by reducing 
survival, increasing energy expenditures, reducing flight and foraging, 
reducing reproduction, and impacting when bees enter diapause 
(Bartomeus et al. 2011, p. 20645; Maebe et al. 2021, p. 4229; Service 
2024, pp. 20-22).
    Bumble bees have low variation in heat stress resistance and, 
therefore, may have low capacity to adapt physiologically to warming 
temperatures (Martinet et al. 2021, p. 7). Bumble bee species that 
occur across a relatively broad climatic range, such as Suckley's 
cuckoo bumble bee, likely have a greater capacity to adapt to warming 
temperatures than species with narrow ranges. While we do not know how 
well Suckley's cuckoo bumble bee will adapt to rising temperatures, 
their main host species, the western bumble bee, appears to be 
sensitive to temperature (Janousek et al. 2023, p. 2). Heat waves are 
projected to increase, particularly in the western portions of North 
America (Hicke et al. 2022, p. 1937), which represents the bulk of the 
Suckley's cuckoo bumble bee's range.
    Temperature changes could make the southern portions of the 
Suckley's cuckoo bumble bee's range less suitable for the species, 
while additional habitat may become more suitable in the northern 
portions of the range and at higher elevations. Colonizing new areas 
may be dependent on dispersal ability and may require adapting to novel 
communities where Suckley's cuckoo bumble bees could be exposed to new 
environmental conditions (e.g., extreme heat or extreme cold) and 
potential hosts (Cameron et al. 2011, pp. 39-40; Pradervand et al. 
2014, p. 5). Additionally, warming ambient temperatures and heatwaves 
commonly co-occur with drought, another influence that could compound 
the effects of any one of the other threats to this species (see 
Drought frequency and intensity, below) (Cameron et al. 2011, pp. 39-
40; Pradervand et al. 2014, p. 5).
    While northern areas may become suitable in the future, an analysis 
of long-term observations of 67 bumble bee species from Europe and 
North America showed southern range contractions as a result of climate 
change, with no change in northern limits (Kerr et al. 2015, p. 178). 
Future projections of the distribution of bumble bee species under 
different climate scenarios and dispersal assumptions also predict 
widespread declines, and possible extirpations, in the southern 
portions of species ranges. (Sirois-Delisle and Kerr 2018, pp. 4-5; 
Soroye et al. 2020, pp. 685, 687).
    Warming temperatures could additionally affect Suckley's cuckoo 
bumble bee and its hosts by affecting floral resources. Shifts in 
flowering

[[Page 102083]]

times (in response to warming temperatures) could result in 
phenological mismatch between pollinators and their foraging resources 
(Service 2024, pp. 47-48). Heatwave conditions directly reduce bumble 
bee foraging, as well as have indirect effects on bumble bee foraging 
from heat-stressed flowering resources (Williams and Hemberger 2023, p. 
597). Decreased pollination due to phenological mismatch could reduce 
plant reproduction and further affect floral resource availability 
(Forrest et al. 2010, p. 438; Thomson 2010, p. 3197).
    Drought frequency and intensity--Drought negatively impacts floral 
resources and the pollinators that depend on them. A large portion of 
Suckley's cuckoo bumble bee's range is within water-limited areas of 
western North America where drought is frequent and has major 
implications for floral resources. The frequency of biologically 
significant drought events is projected to increase within the range of 
Suckley's cuckoo bumble bee and its host species due to changes in 
climate and resource impacts (Swain and Hayhoe 2015, pp. 2737-2750).
    Drought indirectly impacts bumble bees by altering or reducing 
floral resources, including reductions to the quality, quantity, and 
availability of pollen and nectar (Carroll et al. 2001, p. 443; Waser 
and Price 2016, p. 1405; Phillips et al. 2018, pp. 3226-3235) Shifts in 
the spatial and temporal patterns of flowering, which result in mid-
summer floral gaps (Aldridge et al. 2011, entire), highlight that 
drought-stress impacts on a plant community could reduce pollen and 
nectar resources needed for successful pollinator reproduction. Since 
droughts have a direct effect on floral resources, this in turn has an 
effect on pollinators at the population level (Roulston and Goodell 
2011, p. 305). Drought may also lead to increased competition with 
honey bees in areas where their resources overlap. When drought 
conditions impact preferred floral resources, bumble bees will forage 
on less preferred, drought-resistant species sought after by the more 
populous honey bees (Thomson 2016, pp. 1247-1255).
    A model of cumulative effects of climate changes, landcover, and 
pesticide use on western bumble bee occupancy found that consecutive 
years of severe drought was the second most influential cause of 
occupancy declines (Janousek et al. 2023, pp. 2-3). In addition, 
suitable habitats may be restricted with rising temperatures, reducing 
the range of some bumble bee species, especially at range edges where 
abundance may decline when floral resources decline in response to 
drought (Thomson 2016, pp. 1247-1255). Although drought may be locally 
and temporarily alleviated by precipitation, the impacts to the growing 
season may persist and reduced floral resources could impact Suckley's 
cuckoo bumble bees that require pollen and nectar to overwinter with 
adequate body mass (Service 2024, pp. 22-23).
    Droughts, especially in consecutive years (Janousek et al. 2023, p. 
2), will likely amplify biologically significant negative effects on 
Suckley's cuckoo bumble bee resources and host species, though the 
direct drought impacts on Suckley's cuckoo bumble bee individuals and 
populations are unstudied. Droughts are expected to negatively affect 
floral resources, alter floral communities to less preferred flowering 
conditions or timing, increase competition between pollinators, and 
negatively impact Suckley's cuckoo bumble bee and its hosts throughout 
much of the species' range.
    Wildfire--Wildfires pose complex effects to bumble bees, from 
decreasing resource availability (Mola and Williams 2018, p. 7; 
Galbraith et al. 2019, p. 15; Mola et al. 2020, p. 1807) to increasing 
floral and bee abundance and diversity (Mola and Williams 2018, pp. 4-
8; Carbone et al. 2019, entire; Galbraith et al. 2019, entire; Mola et 
al. 2020, pp. 1804-1808). Fire disturbance can temporarily increase 
floral resources, thereby enhancing bee body size, reproductive output, 
genetic diversity, and population size (Carbone et al. 2019, entire; 
Mola et al. 2020, pp. 1804-1808), although these effects may vary by 
habitat type (i.e., forested vs. grassland habitats). The relative 
effect of high-intensity fires varies based on the ecological 
conditions in which they occur. Since Suckley's cuckoo bumble bee is a 
broad-ranging species with multiple hosts, fire is likely to have 
variable and diverse effects throughout its range.
    Early spring frosts--Early spring frosts pose a risk to bumble 
bees, specifically to new queens and newly established colonies, by 
damaging floral resources (CaraDonna and Bain 2015, pp. 61-62). 
Flowers, compared to vegetative parts, are generally more sensitive to 
damage from frost events (CaraDonna and Bain 2015, pp. 61-62), and 
spring frosts reduce the overall availability of floral resource 
abundance across the subsequent summer (CaraDonna et al. 2014, p. 
4919).
    Despite some plants with early phenology exhibiting some tolerance 
to freezing temperatures (CaraDonna and Bain 2015, pp. 61-63), an 
advancing bloom date for plants triggered by climate change (CaraDonna 
et al. 2014, p. 4919) exposes early floral growth to an additional risk 
of frost damage (Willmer 2012, p. R131). The increased frost damage to 
flowering plants could also contribute to an observed change in 
flowering dates across small geographic and altitudinal distributions 
(Inouye 2008, pp. 357, 361).
    Floral resources are important throughout the lifecycles of both 
Suckley's cuckoo bumble bee and its hosts, but they are particularly 
important for host colony establishment in early spring. Negative 
effects of early spring frost on host colony queens, workers, and 
overall colony size may reduce their ability to persist within season, 
and to successfully support Suckley's cuckoo bumble bee. Spring frost 
damage to floral resources has been linked to within-season declines in 
wild bee populations (Graham et al. 2021, p. 6). Spring frosts could 
have a negative impact on the success of local bumble bee colonies 
(Inouye 2008, p. 361) by reducing existing and future within-season 
availability of pollen and nectar resources on which pollinators, 
including host colonies for Suckley's cuckoo bumble bee, rely. 
Inadequate floral resources could especially affect colony 
establishment and growth if they occur during critical times, such as 
early spring when new queens emerge from diapause and are establishing 
their colonies. Delays in emergence or colony initiation after 
emergence may hinder the ability of bees to complete their life cycle 
before the end of the relatively short subarctic season (Vogt et al. 
1994, p. 1554).
Livestock Grazing
    Livestock grazing occurs throughout much of the historical range of 
Suckley's cuckoo bumble bee, primarily by cattle, sheep and wild 
horses, and it can have complex effects on bumble bees. In general, 
grazed sites have reduced floral resources and lower bumble bee 
diversity and abundance (Hatfield and LeBuhn 2007, p. 150; Sj[ouml]din 
2007, pp. 2110-2113; Sj[ouml]din et al. 2008, p. 763). Although grazing 
can be a useful management tool for maintaining early successional 
habitat, benefits are dictated by frequency, intensity, species (i.e. 
sheep, cattle, horses, etc.) and timing (Carvell 2002, p. 44; Kimoto et 
al. 2012, pp. 9-13). Low-intensity grazing preserves floral resources 
benefiting bumble bees (Scohier et al. 2012, pp. 287-292), while 
increased intensity of grazing can reduce bee species richness as a 
result of altered floral composition, including invasive species 
establishment and soil

[[Page 102084]]

compaction (Hatfield and LeBuhn 2007, p. 156; V[aacute]zquez and 
Simberloff 2003, p. 1080). Bumble bees are sensitive to grazing 
intensity early in the season, potentially because of altered foraging 
behavior (Kimoto et al. 2012, pp. 9-13). Intense summer grazing, 
compared to areas only grazed in winter, reduces vegetation height and 
floral resources, leading to fewer bee visits to preferred food plants 
and decreased bumble bee diversity (Xie et al. 2008, pp. 699-700). The 
reduction of vegetation height and structure from high-intensity 
grazing in the Pacific Northwest bunchgrass prairies has been linked to 
declines in bumble bee richness and abundance (Kimoto et al. 2012, pp. 
12-13).
    Grazing may compact soil and change plant communities (Connors 
2016, pers. comm.), thus impacting nesting habitat for Suckley's cuckoo 
bumble bee hosts (Defenders of Wildlife 2015, p. 14). Livestock may 
also trample nesting sites (Kearns et al. 1998, p. 90) and negatively 
impact ground-nesting rodents (Johnson and Horn 2008, p. 444), which in 
turn may reduce the number of nest sites available for bumble bees (The 
Xerces Society and Thorp 2010, p. 13). Livestock grazing also impacts 
hydrology through compaction of soils and degraded riparian areas and 
may lead to increased fire cycles through the introduction of exotic 
species (Dwire et al. 1999, pp. 319-321).
    In summary, grazing can assist in maintaining open habitat, and 
low-intensity grazing can preserve floral resources. However, high-
intensity grazing can have a negative impact on floral resources and 
can negatively impact nest site availability. Thus, grazing has varied 
and complex effects on bumble bees, which makes the impacts difficult 
to analyze.

Conservation Efforts and Regulatory Mechanisms

    Suckley's cuckoo bumble bee is assessed as threatened in Canada 
(COSEWIC, 2019, p. iii) and is listed as critically endangered by the 
International Union for Conservation of Nature (Hatfield et al., 2015, 
p. 1). In the United States, Suckley's cuckoo bumble bee is on the 
sensitive species list for the U.S. Forest Service and Bureau of Land 
Management Interagency Special Status/Sensitive Species Program 
(ISSSSP) in the Pacific Northwest (ISSSSP 2021, entire). It is also 
listed as a species of greatest conservation need in Idaho, Washington, 
Colorado, and California, where it is also a candidate for listing 
under the California Endangered Species Act (Colorado Parks and 
Wildlife 2015, p. B-1; Washington Department of Fish and Wildlife 2015, 
pp. 3-39; Idaho Department of Fish and Game 2017, p. xvii; California 
Natural Diversity Database (CNDDB) 2023, p. 6). These States generally 
outline research and conservation needs for species of greatest 
conservation need in State Wildlife Action Plans, but these plans do 
not offer regulatory protection.
    Some States regulate the import of nonnative bee species, which can 
help protect native bee species, including Suckley's cuckoo bumble bee. 
The Oregon Department of Agriculture restricts some potential sources 
of the pathogen Vairimorpha bombi from entering the State; only Bombus 
species native to Oregon are permitted for commercial pollination 
purposes (Oregon Department of Agriculture 2017, p. 5). California 
requires permits to import some bee species for pollination services 
(California Department of Food and Agriculture 2023, entire).
    The U.S. Forest Service has taken steps to reduce impacts of 
nonnative bee species. The Pacific Northwest Region of the U.S. Forest 
Service is working on finalizing apiary guidelines, which include 
recommendations for management practices and considerations to protect 
native pollinators and minimize negative effects from managed bees and 
apiaries on lands managed by the U.S. Forest Service (Everett 2023, 
pers. comm.). Additionally, at least one U.S. Forest Service National 
Forest in the Pacific Northwest already restricts commercial and 
privately owned bees on their managed lands (Everett 2023, pers. 
comm.). For example, the Colville National Forest plan directs that 
apiaries should not be placed where they would pose a risk to native 
pollinators, butterflies, or rare bee species (U.S. Forest Service 
2019, p. 67). These measures highlight that the U.S. Forest Service 
takes the threat of managed bees seriously and is actively working in 
some regions to protect native bees.
    States have also begun implementing strategies to limit pesticide 
effects on bees. The Oregon Bee Project was initiated in 2017, as a 
collaboration between the Oregon Department of Agriculture, the Oregon 
State University Extension Service, and the Oregon Department of 
Forestry. One project goal is to mitigate bee exposure to pesticides 
through increased pesticide label comprehension, adoption of new 
application practices, and increasing coordination between beekeepers 
and pesticide applicators (Oregon Department of Agriculture et al. 
2022, pp. 2-3). Washington State has established similar goals, as 
stated in their Managed Pollinator Protection Plan, which offers best 
management practices for beekeepers, growers, and pesticide applicators 
to help protect pollinators from pesticides (Washington State 
Department of Agriculture 2018, p. 5). Washington State also adopted 
additional recommendations and funding for pollinator health 
(Washington State Bill 5253, effective July 25, 2021).
    In Washington, neither the Managed Pollinator Protection Plan nor 
State Bill 5253 restrict the use of pesticides, but several other 
States have begun passing regulations on pesticides that are harmful to 
bees and other pollinators. For example, California recently developed 
regulations that will implement mitigation measures to protect 
pollinators by limiting the agricultural uses of certain neonicotinoid 
pesticides, which went into effect January 1, 2024 (California 
Department of Pesticide Regulation 2024, entire). Other States that 
have enacted various regulations on neonicotinoid pesticides to reduce 
impacts to bees and other pollinators include Colorado, Connecticut, 
Maine, Minnesota, Massachusetts, Maryland, Nevada, New York, New 
Jersey, Rhode Island, and Vermont (Malfi 2023, entire).
    Other recent efforts aim to better understand bees at risk and 
implement broader protections. The Pacific Northwest Bumble Bee Atlas 
(a collaborative effort between the Washington Department of Fish and 
Wildlife, the Idaho Department of Fish and Game, the Oregon Department 
of Fish and Wildlife, and the Xerces Society for Invertebrate 
Conservation) seeks to increase understanding of bumble bee 
distributions and their habitats (Washington Department of Fish and 
Wildlife et al. 2023, entire). This effort has contributed to the 
creation of a statewide strategy to protect bumble bee species of 
conservation concern in Washington, with one of the focal species being 
Suckley's cuckoo bumble bee (Martin et al. 2023, p. 12). In Alaska, the 
Alaska Center for Conservation Science at the University of Alaska 
Anchorage and the Bureau of Land Management have developed the Alaska 
Bee Atlas. The program aims to collect data on bee biodiversity within 
Alaska; these data can eventually be used to inform sensitive species 
lists and management (Fulkerson et al. 2023, p. 18). The number of 
bumble bee atlases is increasing across the United States and 
increasingly covering the range of Suckley's cuckoo bumble bee. The 
expanding coverage of these atlases will

[[Page 102085]]

increase understanding of bumble bee status and distribution in North 
America.
    On a broader scale, the Colla Laboratory at York University in 
Toronto has released a national pollinator strategy for Canada. This 
national strategy identifies specific goals and actions to protect 
pollinators and needed research to fill knowledge gaps (Colla and 
Nalepa 2023, p. 5). The Service is also working on a nationwide plan 
through a bumble bee conservation benefit agreement, known as The 
Nationwide Conservation Benefit Agreement for Bumble Bees on Energy and 
Transportation Lands. This conservation benefit agreement is modeled 
after the nationwide monarch butterfly candidate conservation agreement 
with assurances, which is a voluntary agreement with transportation and 
utility landowners that provides incentives for monarch conservation 
measures on their lands. The bumble bee conservation benefit agreement 
will likely include many of the same acres enrolled for the protection 
of several bumble bee species, including Suckley's cuckoo bumble bee 
and some of its host species (i.e., western bumble bee, rusty patched 
bumble bee, and yellow-banded bumble bee). The Nationwide Conservation 
Benefit Agreement for Bumble Bees on Energy and Transportation Lands is 
expected to be completed in 2024 (Everett 2023, pers. comm.).
    Together, these voluntary and regulatory measures highlight an 
increase in effort to protect native bumble bee species across North 
America. Some of these measures specifically target Suckley's cuckoo 
bumble bee, its host species, or both for conservation. Broad efforts 
to protect and conserve native pollinators and bees will also likely 
benefit Suckley's cuckoo bumble bee.

Cumulative Effects

    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report, we have 
analyzed the cumulative effects of identified threats and conservation 
actions on the species. To assess the current and future condition of 
the species, we evaluate the effects of all the relevant factors that 
may be influencing the species, including threats and conservation 
efforts. Because the SSA framework considers not just the presence of 
the factors, but to what degree they collectively influence risk to the 
entire species, our assessment integrates the cumulative effects of the 
factors and replaces a standalone cumulative-effects analysis.

Historical, Current, and Near-Term Condition of Suckley's Cuckoo Bumble 
Bee

    We assessed Suckley's cuckoo bumble bee viability by evaluating the 
historical and current condition and identifying the primary influences 
leading to the species' current and near-term condition. We delineated 
15 analytical units for Suckley's cuckoo bumble bee: 4 in eastern North 
America and 11 in western North America (figure 1). Analytical units 
are based on ecoregions and further detailed in the SSA report (Service 
2024, pp. 55-56).
    We used a published multi-species occupancy model (Jackson et al. 
2022, entire) with updated Suckley's cuckoo bumble bee occurrence 
records (Service 2024, pp. 56-57) to understand trends in both 
Suckley's cuckoo bumble bee and host species occupancy. Our dataset 
included 2,317 occurrence records of Suckley's cuckoo bumble bee. The 
occupancy model also incorporated floral resources and climate 
variables. For a detailed review of the methods, please refer to the 
SSA report (Service 2024, pp. 56-57, 120-123). We provide a summary 
below of the methods and key findings.
    We used the output of the multi-species occupancy model to assess 
historical trends, and to support our assessment of current and near-
term condition. We used decadal projections of rangewide probability of 
occupancy to visualize and characterize overall, rangewide trends in 
occupancy from 1900-2020 (Service 2024, pp. 63-64). We used spatially 
explicit estimates of probability of occupancy from 1900-1960 to 
characterize the historical probability of occupancy in each analytical 
unit; we specifically used 1900-1960 to represent the historical 
baseline, as this is the period before declines were apparent (Service 
2024, pp. 63-64). We used spatially explicit occupancy estimates in 
each analytical unit for the 2000-2020 period to provide a current 
snapshot or baseline of species condition relative to historical. We 
used spatially explicit projections of near-term (2020-2040) occupancy 
in each analytical unit to assess near-term risk of extinction.
    The near-term occupancy projections were made under two scenarios. 
Scenario 1 assumes moderate climate warming under representative 
concentration pathway (RCP) 4.5. Scenario 2 assumes a high warming 
scenario (RCP 8.5), and also projects the observed, historical rates of 
decline due to other, non-climatic (i.e., trend momentum) forward. Both 
scenarios hold floral resources constant at their 2020 levels, as data 
are not available to project this variable forward. Thus, under 
scenario 1, any changes in occupancy are based solely on changes in 
climate (RCP 4.5), while under scenario 2, any changes in occupancy are 
based on both climate change (RCP 8.5), as well as historical rates of 
change due to non-climatic factors. Projections for all host species 
followed the same procedures.
    Suckley's cuckoo bumble bee has exhibited a statistically 
significant decline, resulting in lower occupancy from historical 
condition. Historically, the median probability of occupancy of 
Suckley's cuckoo bumble bee rangewide was 0.65. By the 2000-2020 period 
all analytical units are estimated to have lower probability of 
occupancy, with median probability of occupancy less than 0.16 for all 
analytical units and 0.13 rangewide (table 1).

   Table 1--Median Estimated Probability of Occupancy for Suckley's Cuckoo Bumble Bee in Each Analytical Unit
            During the Historical Period (Average From 1900-1960) and the Current (2000-2020) Period
   [The percent change in median occupancy from historical to current period is also noted for each analytical
unit, as is the total land area of each analytical unit (square kilometers (km\2\)) and the percent of the range
                                  the unit represents, in terms of land area.]
----------------------------------------------------------------------------------------------------------------
                                                                              Median       Median
        Analytical unit           Area (km\2\)    Percent of      Last      historical    current      Percent
                                                    range      detection    occupancy    occupancy      change
----------------------------------------------------------------------------------------------------------------
Atlantic Highlands (East)......          44,482          0.6         1924        0.712        0.149          -79
Boreal Cordillera..............         532,782          7.4         2019        0.706        0.147          -79
Boreal Plains..................         772,369         10.8         2022        0.661        0.145          -78
Brooks Range Tundra............          99,755          1.4         2019        0.705        0.147          -79
Cold Deserts...................       1,047,895         14.7         2011        0.485        0.061          -87
Hudson Plains (East)...........          55,863          0.8         1949        0.682        0.133          -80
Marine West Coast Forests......         250,206          3.5         1982        0.580        0.095          -84

[[Page 102086]]

 
Mixed Wood Plains (East).......         360,958          5.0         1971        0.640        0.106          -83
Mixed Wood Shield..............         205,107          2.9         1995        0.590        0.098          -83
Softwood Shield (East).........         119,152          1.7         2010        0.685        0.142          -79
South Central Semi-Arid                 208,917          2.9         2014        0.118        0.013          -89
 Prairies......................
Taiga Plains...................         905,619         12.7         1969        0.708        0.161          -77
Temperate Prairies.............         501,088          7.0         2018        0.263        0.028          -89
West Central Semi-Arid Prairies         832,871         11.6         2022        0.577        0.100          -83
Western Cordillera.............       1,214,900         17.0         2018        0.692        0.140          -80
                                --------------------------------------------------------------------------------
    Rangewide..................       7,151,965          100     \1\ 2022        0.653        0.128       \2\-85
----------------------------------------------------------------------------------------------------------------
\1\ The last detection of Suckley's cuckoo bumble bee in our dataset was 2022. However, field data from across
  the country from the 2023 field season or beyond had not been fully curated in time to include in the SSA.
\2\ Rangewide decline from 1900 to present, based on an analysis of all Suckley's cuckoo bumble bee occurrence
  records (Service 2024, pp. 63-68).

    Suckley's cuckoo bumble bee has not been observed in the United 
States since 2016, despite widespread historical occurrence records and 
increased sampling effort for bumble bees. Additionally, the species 
has only been detected since 2000 (detections after 2000 are considered 
modern detections) in 9 of the 15 analytical units (60 percent of the 
total analytical units; see table 1, above). We considered analytical 
units to be quasi-extirpated (when the density of reproductive 
individuals in a population becomes so small that extirpation is likely 
inevitable without intervention) if there were no detections since 
2000. In the species' eastern range, three of the four analytical units 
of Suckley's cuckoo bumble bee were considered quasi-extirpated, 
including the Atlantic Highlands (last detection in 1924), Hudson 
Plains (last detection in 1949), Mixed Wood Plains (last detection in 
1971).
    In the west of the species' range, 3 of the 11 analytical units 
lack modern detections (i.e., since 2000) of Suckley's cuckoo bumble 
bee. Notably, the Marine West Coast Forest analytical unit has 515 
historical occurrence records (23 percent of total occurrences), but no 
occurrence records after 1982. The Mixed Wood Shield analytical unit 
has two historical records of the species, with the most recent 
occurrence in 1995. Thus, we consider the Marine West Coast Forest and 
the Mixed Wood Shield analytical units to be quasi-extirpated. Although 
the species has not been observed in the Taiga Plains since 1962, this 
area has not been extensively sampled for bees, and, therefore, we did 
not consider it to be quasi-extirpated.
    Additionally, four (western bumble bee, McKay's bumble bee, rusty 
patched bumble bee, and yellow-banded bumble bee) of six host species 
exhibited statistically significant temporal declines in occupancy 
rangewide (Service 2024, pp. 69-70). These results are similar to other 
studies that found rangewide population declines for bumble bees in the 
subgenus Bombus (Giles and Ascher 2006, pp. 217-218; Colla and Packer 
2008, p. 1387; Schweitzer et al. 2012, p. 7; Janousek et al. 2023, p. 
2;).
    In the near-term (by 2040), probability of occupancy is expected to 
continue to decline. Under scenario 1, median probability of occupancy 
is estimated to be less than 0.11 across all analytical units. This 
represents a 26 to 77 percent decline relative to 2000-2020 estimates. 
Under scenario 2, median probability of occupancy is estimated to be 
less than 0.05 across all analytical units. This represents a 73 to 92 
percent decline relative to 2000-2020 estimates.

Resiliency

    Suckley's cuckoo bumble bee has experienced a statistically 
significant, rangewide, 85 percent decline in occupancy. Additionally, 
the species has not been observed in the contiguous United States since 
2016, despite widespread historical occurrence records and increased 
sampling effort for bumble bees. These results suggest that the species 
is currently found in fewer locations across its range than 
historically. High abundance and survival are demographic needs of 
healthy Suckley's cuckoo bumble bee populations. While there are some 
areas in Canada where the species is still regularly observed, these 
results suggest resiliency is low across all analytical units. In the 
near-term, resiliency is projected to continue to decline, further 
reducing the species ability to sustain populations over time.

Redundancy

    Redundancy buffers the species against catastrophic events and can 
be summarized based on the spatial distribution of sufficiently 
resilient populations relative to catastrophic events. Currently, three 
eastern analytical units and two western analytical units are 
considered quasi-extirpated. This apparent contraction of the range 
results in a loss of redundancy for the species. In the near-term, the 
continued decline in occupancy projected will likely further reduce 
redundancy. Given that one confirmed host species (western bumble bee) 
and three potential host species (rusty patched bumble bee, McKay's 
bumble bee, and yellow-banded bumble bee) are in decline, redundancy in 
terms of host species is considered low. For instance, if a 
catastrophic event wipes out one host species in an area, then there is 
less likely to be an alternative host species available for the 
Suckley's cuckoo bumble bee.

Representation

    Due to estimated and observed declines in occupancy, Suckley's 
cuckoo bumble bee has substantially lower connectivity, and 
representation than historically. Population connectivity is important 
for Suckley's cuckoo bumble bee's viability as it increases the 
likelihood of genetic diversity and promotes successful haplodiploid 
reproduction (genetic sex-determination system in which females develop 
from fertilized (diploid) eggs and males from unfertilized (haploid) 
eggs). Loss of connectivity, genetic drift, and inbreeding may be 
particularly consequential for bumble bees due to their low effective 
population size and their haplodiploid sex determination (Goulson et 
al. 2008, p. 205). However,

[[Page 102087]]

population connectivity is naturally a constraint for cuckoo bumble 
bees because they live in small, fragmented populations due to their 
dependence on host bumble bee colonies (Suhonen et al. 2016, p. 529). 
Dispersal of bees to find unrelated mates is aided by the proximity of 
other usurped host colonies. Consequently, the sharp decrease in the 
prevalence of both Suckley's cuckoo bumble bee and many of its 
confirmed and potential host species has likely reduced population 
connectivity relative to historical conditions. Reduced gene flow may 
have consequences on the genetic diversity of Suckley's cuckoo bumble 
bee, because small populations can experience stronger genetic drift 
(Zayed 2009, p. 246). This is important because high genetic diversity 
reduces prevalence of some pathogens (Parsche and Lattorff 2018, p. 
900), and the risk of matched mating, which produces diploid males that 
do not contribute to population growth (Zayed 2009, p. 239).
    Given the observed 85 percent decrease in the species' occupancy 
relative to historical conditions, the low current and projected near-
term occupancy across all analytical units, and the potential that the 
species is extirpated or quasi-extirpated in portions of its range, the 
species has likely lost representation across longitudinal and 
ecological gradients.
    The adaptive capacity of Suckley's cuckoo bumble bee is also 
dependent on host species, as the distribution of the parasitic bee is 
restricted by the geographic distribution and population health of host 
bees, and parasite abundance is low where host abundance is low 
(Antonovics and Edwards 2011, p. 1003). Therefore, availability of host 
species may also indirectly restrict the adaptive capacity of Suckley's 
cuckoo bumble bee, given that four of the six host species are also in 
decline.

Future Condition

    As part of the SSA, the same methods to model near-term condition 
were also used to mode the two future condition scenarios out to the 
year 2100. Our scenarios assumed a moderate to major increase in 
climate change (warming conditions) and either a continuation of 
factors that resulted in the historical decline of the species, or no 
continuation of these factors (just the impacts of climate change) to 
the species. Because we determined that the current and near-term 
condition of Suckley's cuckoo bumble bee is consistent with the Act's 
definition of an endangered species (see Determination of Suckley's 
Cuckoo Bumble Bee's Status, below), we are not presenting the results 
of the future scenarios beyond 2040 in this proposed rule. Please refer 
to the SSA report (Service 2024, pp. 73-83) for the full analysis of 
future conditions.

Determination of Suckley's Cuckoo Bumble Bee's Status

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of an endangered species or a 
threatened species. The Act defines an ``endangered species'' as a 
species in danger of extinction throughout all or a significant portion 
of its range and a ``threatened species'' as a species likely to become 
an endangered species within the foreseeable future throughout all or a 
significant portion of its range. The Act requires that we determine 
whether a species meets the definition of an endangered species or a 
threatened species because of any of the following factors: (A) The 
present or threatened destruction, modification, or curtailment of its 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence.
    We presented summary evaluations of the main drivers of the 
species' current and near-term condition analyzed in the SSA report 
including habitat conversion and fragmentation (Factor A), livestock 
grazing (Factor A), pathogens (Factor C), host species decline (Factor 
E), climate change (Factor E), and pesticides (Factor E). We also 
evaluated existing regulatory mechanisms (Factor D) and ongoing 
conservation measures.

Status Throughout All of Its Range

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we have determined that Suckley's cuckoo bumble bee has 
limited resiliency, redundancy, and representation to maintain 
viability over time. Suckley's cuckoo bumble bee has exhibited a 
statistically significant decline (85 percent) in probability of 
occupancy rangewide. Historically, the median probability of occupancy 
of Suckley's cuckoo bumble bee rangewide was 0.65. By the current time 
period (2000-2020), all analytical units are estimated to have lower 
probability of occupancy, with median probability of occupancy less 
than 0.16 for all analytical units and 0.13 rangewide. In the near-term 
(by 2040), the probability of occupancy is projected to continue to 
decline, with probability of occupancy for all analytical units 
projected to be below 0.05 (scenario 1) and 0.11 (scenario 2). 
Additional analyses of host species occupancy indicate that four of six 
known or potential host species exhibited statistically significant 
temporal declines in probability of occupancy rangewide. Thus, 
resiliency for all analytical units is considered low.
    Suckley's cuckoo bumble bee has lost redundancy because 5 of the 15 
analytical units are currently considered to be in a quasi-extirpated 
state, the species has not been observed in the contiguous United 
States since 2016, and the remaining analytical units are all 
considered to have low resiliency. Near-term projections indicate 
continued declines in occupancy, further reducing redundancy.
    Representation has also declined as a result of range contraction 
and occupancy decline, as phenotypic, genetic, and ecological diversity 
have declined. As host colonies become less common across the 
landscape, Suckley's cuckoo bumble bees will likely have lower 
likelihood of finding unrelated mates. Population fragmentation, 
genetic drift, and inbreeding are likely to be exacerbated in the near-
term as the species becomes even less prevalent. Finally, it is 
important to note that the viability of Suckley's cuckoo bumble bee is 
also highly dependent on its host species, many of which have declined 
historically, and are expected to continue to do so in the near-term.
    We do not find Suckley's cuckoo bumble bee meets the Act's 
definition of a threatened species because the species currently has 
low resiliency, redundancy, and representation and near-term 
projections are estimated to further reduce overall species viability. 
Because Suckley's cuckoo bumble bee has low redundancy and 
representation, the species is vulnerable to even a single catastrophic 
event such as a pathogen outbreak, wildfire, or drought event. Thus, 
after assessing the best scientific and commercial data available, we 
determine that Suckley's cuckoo bumble bee is in danger of extinction 
throughout all of its range.

Status Throughout a Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. We have determined that Suckley's cuckoo bumble bee is in 
danger of extinction throughout all of its range and

[[Page 102088]]

accordingly did not undertake an analysis of any significant portion of 
its range. Because Suckley's cuckoo bumble bee warrants listing as 
endangered throughout all of its range, our determination does not 
conflict with the decision in Center for Biological Diversity v. 
Everson, 435 F. Supp. 3d 69 (D.D.C. 2020), because that decision 
related to significant portion of the range analyses for species that 
warrant listing as threatened, not endangered, throughout all of their 
range.

Determination of Status

    Based on the best scientific and commercial data available, we 
determine that Suckley's cuckoo bumble bee meets the Act's definition 
of an endangered species. Therefore, we propose to list Suckley's 
cuckoo bumble bee as an endangered species in accordance with sections 
3(6) and 4(a)(1) of the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition as a listed 
species, planning and implementation of recovery actions, requirements 
for Federal protection, and prohibitions against certain practices. 
Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies, foreign 
governments, private organizations, and individuals. The Act encourages 
cooperation with the States and other countries and calls for recovery 
actions to be carried out for listed species. The protection required 
by Federal agencies, including the Service, and the prohibitions 
against certain activities are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Section 4(f) of the Act calls for the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The goal of this process is to restore listed 
species to a point where they are secure, self-sustaining, and 
functioning components of their ecosystems.
    The recovery planning process begins with development of a recovery 
outline made available to the public soon after a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions while a recovery plan is being developed. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) may be 
established to develop and implement recovery plans. The recovery 
planning process involves the identification of actions that are 
necessary to halt and reverse the species' decline by addressing the 
threats to its survival and recovery. The recovery plan identifies 
recovery criteria for review of when a species may be ready for 
reclassification from endangered to threatened (``downlisting'') or 
removal from protected status (``delisting''), and methods for 
monitoring recovery progress. Recovery plans also establish a framework 
for agencies to coordinate their recovery efforts and provide estimates 
of the cost of implementing recovery tasks. Revisions of the plan may 
be done to address continuing or new threats to the species, as new 
substantive information becomes available. The recovery outline, draft 
recovery plan, final recovery plan, and any revisions will be available 
on our website as they are completed (https://www.fws.gov/program/endangered-species) or from our Southern Alaska Fish and Wildlife Field 
Office (see FOR FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    If this species is listed, funding for recovery actions will be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the 
academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the States of Washington, Oregon, 
Idaho, California, Colorado, Nevada, Utah, Arizona, Wyoming, Montana, 
North Dakota, South Dakota, Nebraska, and Minnesota would be eligible 
for Federal funds to implement management actions that promote the 
protection or recovery of the Suckley's cuckoo bumble bee. Information 
on our grant programs that are available to aid species recovery can be 
found at: https://www.fws.gov/service/financial-assistance.
    Although Suckley's cuckoo bumble bee is only proposed for listing 
under the Act at this time, please let us know if you are interested in 
participating in recovery efforts for this species. Additionally, we 
invite you to submit any new information on this species whenever it 
becomes available and any information you may have for recovery 
planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7 of the Act is titled, ``Interagency Cooperation,'' and it 
mandates all Federal action agencies to use their existing authorities 
to further the conservation purposes of the Act and to ensure that 
their actions are not likely to jeopardize the continued existence of 
listed species or adversely modify critical habitat. Regulations 
implementing section 7 are codified at 50 CFR part 402.
    Section 7(a)(2) states that each Federal action agency shall, in 
consultation with the Secretary, ensure that any action they authorize, 
fund, or carry out is not likely to jeopardize the continued existence 
of a listed species or result in the destruction or adverse 
modification of designated critical habitat. Each Federal agency shall 
review its action at the earliest possible time to determine whether it 
may affect listed species or critical habitat. If a determination is 
made that the action may affect listed species or critical habitat, 
formal consultation is required (50 CFR 402.14(a)), unless the Service 
concurs in writing that the action is not likely to adversely affect 
listed species or critical habitat. At the end of a formal 
consultation, the Service issues a biological opinion, containing its 
determination of whether the Federal action is likely to result in 
jeopardy or adverse modification.
    In contrast, section 7(a)(4) of the Act requires Federal agencies 
to confer with the Service on any action which is likely to jeopardize 
the continued existence of any species proposed to be listed under the 
Act or result in the destruction or adverse modification of critical 
habitat proposed to be designated for such species. Although the 
conference procedures are required only when an action is likely to 
result in jeopardy or adverse modification, action agencies may 
voluntarily confer with the Service on actions that may affect species 
proposed for listing or critical habitat proposed to be designated. In 
the event that the subject species is listed or the relevant critical 
habitat is designated, a conference opinion may be adopted as a 
biological

[[Page 102089]]

opinion and serve as compliance with section 7(a)(2) of the Act.
    Examples of discretionary actions for Suckley's cuckoo bumble bee 
that may be subject to conference and consultation procedures under 
section 7 are management of Federal lands administered by the National 
Park Service, U.S. Fish and Wildlife Service, and U.S. Forest Service, 
as well as actions that require a Federal permit (such as a permit from 
the U.S. Army Corps of Engineers under section 404 of the Clean Water 
Act (33 U.S.C. 1251 et seq.) or actions funded by Federal agencies such 
as the Federal Highway Administration, Federal Aviation Administration, 
or the Federal Emergency Management Agency. Federal actions not 
affecting listed species or critical habitat--and actions on State, 
Tribal, local, or private lands that are not federally funded, 
authorized, or carried out by a Federal agency--do not require section 
7 consultation. Federal agencies should coordinate with the Southern 
Alaska Fish and Wildlife Field Office (see FOR FURTHER INFORMATION 
CONTACT) with any specific questions on section 7 consultation and 
conference requirements.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to endangered wildlife. 
The prohibitions of section 9(a)(1) of the Act, and the Service's 
implementing regulations codified at 50 CFR 17.21, make it illegal for 
any person subject to the jurisdiction of the United States to commit, 
to attempt to commit, to solicit another to commit or to cause to be 
committed any of the following acts with regard to any endangered 
wildlife: (1) import into, or export from, the United States; (2) take 
(which includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect, or to attempt to engage in any such conduct) 
within the United States, within the territorial sea of the United 
States, or on the high seas; (3) possess, sell, deliver, carry, 
transport, or ship, by any means whatsoever, any such wildlife that has 
been taken illegally; (4) deliver, receive, carry, transport, or ship 
in interstate or foreign commerce, by any means whatsoever and in the 
course of commercial activity; or (5) sell or offer for sale in 
interstate or foreign commerce. Certain exceptions to these 
prohibitions apply to employees or agents of the Service, the National 
Marine Fisheries Service, other Federal land management agencies, and 
State conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations 
governing permits for endangered wildlife are codified at 50 CFR 17.22, 
and general Service permitting regulations are codified at 50 CFR part 
13. With regard to endangered wildlife, a permit may be issued: for 
scientific purposes, for enhancing the propagation or survival of the 
species, or for take incidental to otherwise lawful activities. The 
statute also contains certain exemptions from the prohibitions, which 
are found in sections 9 and 10 of the Act.

II. Critical Habitat

Background

    Section 4(a)(3) of the Act requires that, to the maximum extent 
prudent and determinable, we designate a species' critical habitat 
concurrently with listing the species. Critical habitat is defined in 
section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species, and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Our regulations at 50 CFR 424.02 define the geographical area 
occupied by the species as an area that may generally be delineated 
around species' occurrences, as determined by the Secretary (i.e., 
range). Such areas may include those areas used throughout all or part 
of the species' life cycle, even if not used on a regular basis (e.g., 
migratory corridors, seasonal habitats, and habitats used periodically, 
but not solely by vagrant individuals).
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that each Federal action agency ensure, in 
consultation with the Service, that any action they authorize, fund, or 
carry out is not likely to result in the destruction or adverse 
modification of designated critical habitat. The designation of 
critical habitat does not affect land ownership or establish a refuge, 
wilderness, reserve, preserve, or other conservation area. Such 
designation also does not allow the government or public to access 
private lands. Such designation does not require implementation of 
restoration, recovery, or enhancement measures by non-Federal 
landowners. Rather, designation requires that, where a landowner 
requests Federal agency funding or authorization for an action that may 
affect an area designated as critical habitat, the Federal agency 
consult with the Service under section 7(a)(2) of the Act. If the 
action may affect the listed species itself (such as for occupied 
critical habitat), the Federal agency would have already been required 
to consult with the Service even absent the designation because of the 
requirement to ensure that the action is not likely to jeopardize the 
continued existence of the species. Even if the Service were to 
conclude after consultation that the proposed activity is likely to 
result in destruction or adverse modification of the critical habitat, 
the Federal action agency and the landowner are not required to abandon 
the proposed activity, or to restore or recover the species; instead, 
they must implement ``reasonable and prudent alternatives'' to avoid 
destruction or adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific data available, those physical or biological features that 
are essential to the conservation of the species (such as space, food, 
cover, and protected habitat).
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas

[[Page 102090]]

outside the geographical area occupied by the species at the time it is 
listed, upon a determination that such areas are essential for the 
conservation of the species.
    Section 4(b)(2) of the Act requires that we designate critical 
habitat on the basis of the best scientific data available. Further, 
our Policy on Information Standards Under the Endangered Species Act 
(published in the Federal Register on July 1, 1994 (59 FR 34271)), the 
Information Quality Act (section 515 of the Treasury and General 
Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; 
H.R. 5658)), and our associated Information Quality Guidelines provide 
criteria, establish procedures, and provide guidance to ensure that our 
decisions are based on the best scientific data available. They require 
our biologists, to the extent consistent with the Act and with the use 
of the best scientific data available, to use primary and original 
sources of information as the basis for recommendations to designate 
critical habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information compiled in the SSA report and information developed during 
the listing process for the species. Additional information sources may 
include any generalized conservation strategy, criteria, or outline 
that may have been developed for the species; the recovery plan for the 
species; articles in peer-reviewed journals; conservation plans 
developed by States and counties; scientific status surveys and 
studies; biological assessments; other unpublished materials; or 
experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to: (1) Conservation 
actions implemented under section 7(a)(1) of the Act; (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to ensure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species; and (3) the prohibitions found in section 9 of the Act. 
Federally funded or permitted projects affecting listed species outside 
their designated critical habitat areas may still result in jeopardy 
findings in some cases. These protections and conservation tools 
continue to contribute to recovery of the species. Similarly, critical 
habitat designations made on the basis of the best scientific data 
available at the time of designation will not control the direction and 
substance of future recovery plans, habitat conservation plans (HCPs), 
or other species conservation planning efforts if new information 
available at the time of those planning efforts calls for a different 
outcome.

Critical Habitat Determinability

    Our regulations at 50 CFR 424.12(a)(2) state that critical habitat 
is not determinable when one or both of the following situations exist:
    (i) Data sufficient to perform required analyses are lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to identify any area that meets the definition of ``critical 
habitat.''
    We reviewed the available information pertaining to the biological 
needs of the species and habitat characteristics where this species is 
located. A careful assessment of the economic impacts that may occur 
due to a critical habitat designation is still ongoing, and we are in 
the process of acquiring the complex information needed to perform that 
assessment. Therefore, due to the current lack of data sufficient to 
perform required analyses, we conclude that the designation of critical 
habitat for Suckley's cuckoo bumble bee is not determinable at this 
time. The Act allows the Service an additional year to publish a 
critical habitat designation that is not determinable at the time of 
listing (16 U.S.C. 1533(b)(6)(C)(ii)).

Required Determinations

Clarity of the Rule

    We are required by E.O.s 12866 and 12988 and by the Presidential 
Memorandum of June 1, 1998, to write all rules in plain language. This 
means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in ADDRESSES. To better help us 
revise the rule, your comments should be as specific as possible. For 
example, you should tell us the numbers of the sections or paragraphs 
that are unclearly written, which sections or sentences are too long, 
the sections where you feel lists or tables would be useful, etc.

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951, May 4, 1994), E.O. 13175 (Consultation and 
Coordination with Indian Tribal Governments), the President's 
memorandum of November 30, 2022 (Uniform Standards for Tribal 
Consultation; 87 FR 74479, December 5, 2022), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with federally recognized 
Tribes and Alaska Native Corporations (ANCs) on a government-to-
government basis. In accordance with Secretary's Order 3206 of June 5, 
1997 (American Indian Tribal Rights, Federal-Tribal Trust 
Responsibilities, and the Endangered Species Act), we readily 
acknowledge our responsibilities to work directly with Tribes in 
developing programs for healthy ecosystems, to acknowledge that Tribal 
lands are not subject to the same controls as Federal public lands, to 
remain sensitive to Indian culture, and to make information available 
to Tribes. We sent letters to all Tribes within the range of the 
species. We received responses back from the Tsleil-Waututh Nation and 
the Nottawaseppi Huron Band of the Potawatomi; both Tribes provided 
support for our SSA efforts, but no new data or information. We will 
continue to work with Tribal entities during the development of any 
subsequent rules for Suckley's cuckoo bumble bee.

References Cited

    A complete list of references cited in this rulemaking is available 
on the internet at https://www.regulations.gov and upon request from 
the Southern Alaska Fish and Wildlife Field Office (see FOR FURTHER 
INFORMATION CONTACT).

Authors

    The primary authors of this proposed rule are the staff members of 
the Fish and Wildlife Service's Species

[[Page 102091]]

Assessment Team and the Southern Alaska Fish and Wildlife Field Office.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Plants, 
Reporting and recordkeeping requirements, Transportation, Wildlife.

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, 
unless otherwise noted.

0
2. In Sec.  17.11, in paragraph (h), amend the List of Endangered and 
Threatened Wildlife by adding an entry for ``Bee, cuckoo bumble, 
Suckley's'' in alphabetical order under INSECTS to read as follows:

Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                          Listing citations and
           Common name              Scientific name        Where listed        Status        applicable rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
             Insects
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Bee, cuckoo bumble, Suckley's...  Bombus suckleyi....  Wherever found.....            E  [Federal Register
                                                                                          citation when
                                                                                          published as a final
                                                                                          rule].
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2024-28729 Filed 12-16-24; 8:45 am]
BILLING CODE 4333-15-P
```