U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Pollinating Insect-Biology, Management, Systematics Research: Logan, UT
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Logan, Utah Pollinating Insect-Biology, Management, Systematics Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications
- Bee Lab Main
- Bee Mail Shelter
- Bumble Bee Rearing Guide
- Blue Orchard Bee - Fact Sheet
- Blue Orchard Bee Rearing Guide
- Build a Nesting Block
- Gardening & Landscaping Practices for Nesting Native Bees
- Gardening for Native Bees in N. America
- Hang Tags for Flowers
- Ozone to Decontaminate Honey Bee Supers
- Pollen Traps
- Reed Nests
- Stick Nests
- Alfalfa Leafcutting Bee (ALCB)
- Blue Orchard Bee
- Bumble Bee
- Bumble Bee Utah Quickguide
- Bumble Bees of the Pacific Northwest
- Monitoring Bumble Bees in the Pacific Northwest
- Bumble Bees Western U.S. Guide
- U.S. National Pollinating Insects Collection
- What are Bees?
- Pollinator Of The Month
- Bee Lab Main

Title:   Author  item
                                            James, Rosalinditem
                                            Pitts Singer, Theresa
  Submitted to: Environmental Entomology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 8/8/2013
                                    Publication  Date: 12/12/2013
                                    Citation: James, R.R., Pitts Singer, T. 2013. Health status of alfalfa leafcutting bee larvae (Hymenoptera:  Megachilidae) in commercial United States alfalfa seed fields. Environmental Entomology. 42(6):1166-1173.Interpretive Summary: The alfalfa leafcutting bee is used extensively for pollinating alfalfa seed crops. Its commercial value as a pollinator is second only to honey bees.  Unfortunately, like honey bees, it suffers from health issues that have made it more difficult to propagate.  We conducted a geographically broad survey at the end of the nesting season to evaluate the causes for bee production losses in alfalfa seed fields. Healthy larvae were found in only 47% of the nest cells. The largest production losses were due to a condition called pollen ball (a nest cell with food but no larva)(16.7%), larvae killed by a disease called chalkbrood (8.0%), and larvae that died for no apparent reason (15.5%).  Frequency of pollen balls was related to the number of adult bees used per hectare and the age of the alfalfa stands. The unknown mortality corresponded with the USDA plant hardiness zone.  Since warmer climates have higher plant hardiness zone designations, this mortality appears to be associated with warmer climates, but the results were not conclusive. The frequency of chalkbrood was correlated with using fewer bees per hectare and more shelters, but the correlations were not strong and so may be due to other factors that were not accounted for.  Interestingly, occurrence of this disease was not affected by nesting board disinfection practices. Vapona is an insecticide used to control parasitoids in the parent bees. This fumigant treatment was associated with an increase in both chalkbrood and the onset of winter dormancy in the larvae.  How this adult treatment could affect the offspring in this way can only be speculated. This survey quantifies the variation in the quality of alfalfa leafcutting bees in commercial populations produced across most of the U.S. alfalfa seed production area.
                                Technical Abstract: We conducted a geographically large survey to quantify production losses in the alfalfa leafcutting bee (Megachile rotundata, Hymenoptera: Megachilidae), a solitary pollinator used extensively in alfalfa seed production. Healthy prepupae were found in only 47.1% of the nest cells collected at the end of the season. Most other cells contained pollen balls (typified by a provision but no larva)(16.7%), unknown causes of larval mortality (15.5%), or larvae killed by chalkbrood (8.0%).  Prevalence of pollen balls was correlated positively with bee release rates and negatively with alfalfa stand age. The unknown mortality was correlated with the USDA plant hardiness zone, and thus, some of the mortality may be caused by high temperature extremes, although the nesting season degree days was not correlated. Chalkbrood prevalence was correlated with possible nesting-resource or crowding related factors, such as the number of bees released per hectare and the number of shelters used, but not with nesting board disinfection practices. Vapona® is used to control parasitoids when the parent bees are incubated prior to release. This fumigant was associated with an increase in both chalkbrood and diapausing offspring, although any reason for these correlations are unknown. This survey quantifies the variation in the quality of alfalfa leafcutting bee commercial populations produced across much of the U.S. alfalfa seed production area.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov