United States

Department of

Agriculture

0

54sa Forest Service

Southern Forest

Research Note

so -357

Experiment Station November 1989

A Key to Phoretic Mites Commonly Found on Long-Horned

Beetles Emerging from Southern Pines

D. N. Kinn and M. J. Linit

INTRODUCTION METHODS

Long-horned beetles that attack conifers are usually

considered secondary pests because they generally

develop in dead and dying trees and are not the cause of

tree mortality (Drooz 1985). Recently that status has

changed with the realization that a number of species,

especially those belonging to the genus Mo?zochul?zus,

are vectors of the pinewood nematode, Bursuphelenchus

xylophifus (Steiner and Buhrer). This nematode is the

causative agent of pine wilt disease. Most species of

conifers endemic to North America are resistant to the

wilt disease, but many exotic species are highly susceptible. The introduction of this nematode into Japan had

devastating effects on the native pines in that country

(Mamiya 1972), and trade restrictions now exist to

prevent the introduction of this pathogen into Europe.

Eleven loblolly pine trees (Pinus tuedu L.) were felled

beginning in the spring of 1982 and ending in June 1985.

These trees remained in the field from 10 days to several

months until numerous oviposition pits of long-horned

beetles were present and larval activity could be heard.

Billets were then cut from these trees and transported to

a greenhouse where they were placed in rearing containers for 3 to 8 months, depending on the season.

Beetles emerging from these billets were collected daily

as they emerged and the mites removed and identified as

to species.

RESULTS AND DISCUSSION

It has been suggested that several mite species associated with the principal vector in Japan, Monochamus

alternutus Hope, may prey upon this nematode (Enda

and Brmura 1977). Cursory observations of some of the

mites associated with species of long-horned beetles attacking southern pines also indicate that some of these

mites are nematophagous (Kinn 1986).

A first step in the determination of possible natural

enemies of either the nematode or its insect vector is to

survey the associated fauna. In regard to the acarine

fauna, this step has been taken (Kinn 1986). The next

step is to identify these mites, a difficult task for researchers unfamiliar with mites. IIb facilitate identification of mites commonly found associated with adult

cerambycids emerging from southern pines, a key to the

phoretic and/or parasitic forms has been prepared. Only

one stage in the life cycle of each mite species is phoretic.

In some cases this may be an adult stage, but it is often

an immature stage such as the second nymphal stage,

termed a deutonymph or the larval stage. The key is

limited to the mite species found in our samples.

Five cerambycid species emerged from the field-collected bolts (table 1). Monochumus titillator (F.) and

Neucunthocinus obsoletus (Olivier) were the most

numerous. Of these two species, M. titillutor appears to

be a more efficient vector of the pinewood nematode

(Klnn 1986). Monochumus Caroline&s (Olivier) is also

an efficient vector (Linit and others 1983). Neucunthocinus obsoletus and M. curolinensis have fewer mite

associates than M. titillator. This may be due to behavioral differences among these species. Neucunthocinus obsoletus pupates at the phloem-xylem

interface, whereas Monochumus spp. pupate within the

xylem. Monochumus curolinensis tends to oviposit on

thin-bark trees or on the thin bark sections of trees (Linit

and others 1983). This may also account for the low

numbers of M. curolinensis reared from our bolts, since

most were taken from the lower, thicker barked section

of the trees. Thirteen species of mites were associated

with the long-horned beetles collected (appendix).

The mite species commonly found associated with

scolytids, such as Lkndroluelups neodisetus (Hurlbutt),

TIichouropodu uustrulis Hirschmann, and Histiostomu

Southern Forest Experiment Station/l-102lO U.S. Postal Services Bldg., 701 Loyola Avenue, New Orleans, La. 70113

Forest Service, U.S. Department of Agriculture.

Serving Alabama, Arkansas, Louisiana, Mississippi, E. Oklahoma, Tennessee, E. Texas, Puerto Rico, U.S. Virgin Islands

1
lhble l.-Phoretic mites found on cerambycid beetles emetgingfiom field-collected bolts

Cerambycid beetles*

Mites Monochamus Monochamus Neacanthosinus xy10tcrus ljlocerina

titillator camlinensis obsoletus sa&atus nodosa

(F.) (278) (Olivier) (23) (Olivier) (203) (Get-mar) (134) (F.) (8)

Mucroseius monochami (Adult female) X

Longoseius cuniculus (Dnym)t X

Lkuirolaelaps isodentatus (Dnym) X

Lkndrolaelaps varipunctatw (Dnym) X X X X

Dendrolaelaps neodisetus (Dnym) X X X

l?ichouropoda lamellosa (Dnym) X X X X

lkhouropoda hirsuta (Dnym) X X X X

lMwuropoda australis (Dnym) X

Eutogenes vicinus (Adult female) X

Tarsonemus subcorticalis (Adult female) X X

Neotrombidium tricuspidurn (Lar) X X X X

Histiogaster arborsignis (Dnym) X X X X

Histiostoma varia (Dnym) X

*Number in parentheses is the number of beetles examined.

tDnym=deutonymph.

varia (Woodring and Moser), are rarely associated with

long-horned beetles. The reverse is also true. Most of the

mites commonly found on long-horned beetles are rarely

found associated with scolytids. Histioguster urborsignis

Woodring is the only mite commonly found associated

with both bark beetles and long-horned beetles. Several

mite species were found only on N obsoletus. This may

be due to the habit of N. obsoletus pupating at the

phloem-xylem interface rather than within a pupal cell

excavated from the xylem.

Additional sampling would probably reveal additional acarine species associated with long-horned beetles

present in southern pines. Therefore, it would be prudent to have an acarologist confirm identifications made

with the following key. The mite species listed here may

or may not be present on other species of long-horned

beetles attacking pines in other areas of North America.

AN ARTIFICIAL KEY TO PHORETIC MITES

COMMONLY FOUND ON LONG-HORNED

BEETLES EMERGING FROM

SOUTHERN PINE BOLTS

1. Usually large mites (over 0.3 mm); often with distinctive tanned dorsal and ventral shields (figs. 1-5); with

a pair of median pincerlike and toothed mouthparts

(chelicerae) (fig. SB); respiratory openings (stigmata)

located at level of legs II to IV (fig.l), and surrounded

by a sclerotized groove (peritreme) that often extends

anteriorly (fig. 3); a hairlike or forked structure

(tritosternum) present between or beneath bases of leg

I (fig. 1) [Parasitiformes] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1’. Small mites (0.3 mm or smaller); usually whitish in

color; shields, if present, not as above; median mouthparts absent or needlelike; respiratory openings not

located between legs II to IV, tritosternum absent

[Acariformes] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

2. Turtle-shaped; shielded margin of body with numerous

scallops, most of which have a single hair; bases of legs

I contiguous (figs. 1, 2); attachment to beetle is by

means of an analstalk. [Uropodoidea] . . . . . . . . . . . . . . . . . . . . . . . 3

2’. Not turtle-shaped; bases of legs I well separated;

attachment to host is by mouthparts and/or claws on

the legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

3. Ventral shield with five pairs of hairs; depressed spots

present o n sternogenital shield (fig. 1 ) . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .l’khouropodu hirsutu

3’. Ventral shield with six or seven pairs of hairs;

depressed spots absent on sternogenital shield . . . . . . . . . . 4

4. Sternogenital shield with five pairs of hairs; ventral

shield with six pairs of hairs (fig. 2A) . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lfichouropodu lumellosu

D. N. Kinn is research entomologist, U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station, Pineville, LA 71360. hf.

J. Linit is associate professor, Department of Entomology, University of Missouri, Columbia, MO 65211.

The authors wish to thank the staff and students of the University of Missouri and the Forest Service personnel who evaluated the key, and P E.

Hunter, G. W. Frantz, and E. E. Lindquist for their constructive suggestions on the initial draft of the manuscript.

2

I

_.“..
4’. Sternogenital shield with six pairs of hairs; ventral

shield with seven pairs of hairs (fig. 2B) . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .lfichouropoda australis

5. Dorsum covered by one shield; genital shield separated

from sternal shield (fig. 3) . . . . . . . . Mucroseius monochami

5’. Dorsum covered by two shields (figs. 4-6); genital

shield not separated from sternal shield (fig. 6A

[Digamasellidae] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

6. Body elongate, about four times longer than wide (fig.

4 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Longoseius cuniculus

6’. Body not elongate, about two times longer than wide

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

7. With four equally long posterior body hairs; middle

tine of epistome (dorsal covering of mouthparts)

broader and longer than lateral tines (fig. 5) . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Dendrolaelaps isodentatus

7 . With two or four long posterior body hairs; if four,

then one pair is at least twice the length of the other;

middle tine of epistome shorter than lateral tines . . . . . . 8

8. With two long posterior body hairs; without platelets

between dorsal shields (fig. 6B); inner border of

peritreme not wavy . . . . . . . . . . . . . . . . Dendrolaelaps neodisetus

8’. With four long posterior body hairs, outer pair longer

than inner pair; with two platelets between dorsal

shields; inner border of peritreme wavy (fig. 6C) . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Dendrolaelaps varipunctatus

Ste

Tritosternum

\

Depressed a>

9. Mouthparts apparent; anal suckers absent (figs. 7A, B;

8C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

9. Mouthparts not apparent; special anal suckers

present (fig. 8A, B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

10. With three pairs of legs; dorsum with one pair of long

sensory hairs; other dorsal hairs moderately long, thick,

and pilose, each set on an individual platelet (fig. 7A)

. . . . . . . ..“.................................. Neotrombidium tricuspidum

lO’.With four pairs of legs; legs IV may bear claws or

appear hairlike; dorsum without long sensory hairs;

dorsal hairs not set on individual platelets . . . . . . . . . . . . . . . . .1 1

11. All legs similar in size; legs IV with claws; dorsal hairs

fanlike; mouthparts large, with elaborate appendages

(fig. 7B); ventral body apodemes (ridges) absent . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Eutogenes vicinus

11’. Legs IV smaller then others, without claws, terminating in whiplike hairs; dorsal hairs not fanlike, but one

pair prominently club-shaped; mouthparts indistinct,

without elaborate appendages (fig. SC); a series of

ventral body apodemes present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tarsonemus subcorticalis

12. All legs similar in form; legs III and IV directed

backwards, their distal segments short (fig. 8A) . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . ..*....................... Histiogaster arborsignis

12’. Leg III and IV more slender than legs I and II,

directed forwards, their distal segments elongate (fig.

8B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Histiostoma varia

Contiguous

bases of legs I

”

lk arginalh scallops

Ventral shield

.2 mm

Figure I.-Ventral body view of l’tichouropoda himta deutonymph.

3
Figure 2.- Vewal body view of: (A) llichouropoda lamellosa deutonymph; (B)

‘lkichouropoda australis deutonymph.

Ad I Separate bases

Peritreme

of legs I

Sternal

shield

Figure 3.-Kwral body view ofh4ucroseius monochami adult female.

4
Figure 4.-Dorsal body view of Longoseius cuniculus

deutonymph

Long posterior

body- hairs

Figure 5.-Dendrolaelaps isodentatus deutonymph: (A) dorsal body view; (B)

chelicera.

I

5
rJ% Perltreme \

posterior body hairs

Figure ofi Dendrolaelaps neodisetus deutonymph, venter; (B)

Dendrolaelaps neodisetus deutonymph, dorsum; (C) Dendrolaelaps

varipunctatus deutonymph, dorsum.

Palps

Figure 7.- Body view of {A) Neotrombidium tricuspidum larva, ahum; (B) Eutogenes

vicinus adult female, dorsum.

6
A

Reduced mouthparts

I /

\ ‘Ana’ suckers Reduced

i \ /

mouthpar

Figure 8.-B&y view of: (A) Histiogaster arborsignis deuronymph, venter; (B) Histiostoma

varia venter; (C) ‘Ihrsonemus subcorticalis adult female, venter.

7
LITERATURE CITED

Drooz, A. T, ed. 1985. Insects of eastern forests. Misc.

Publ. 1426. Washington, DC: U.S. Department of

Agriculture. 608 p.

Enda, N. and H. ‘Iamura. 1977. Nematophagous mites

detected on adult Monochum& alfernarus Hope. Forest

Pests. 26(12): 2-4. In Japanese.

Kinn, D. N. 1986. Incidence of pinewood nematode

dauerlarvae and phoretic mites associated with longhorned beetles in central Louisiana. Canadian Journal

of Forest Research. 17: 187-190.

Linit, M. J., E. Kondo, and M. T Smith. 1983. Insects

associated with the pinewood nematode, Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae), in Missouri. Environmental Entomology.

12(2): 467470.

Mamiya, Y. 1972. Pine wood nematode, Bursaphelenchus

Zignicolus Mamiya and Kiyohara, as a causal agent of

pine wilting disease. Review of Plant Protection Research. 5: 46-60.

Appendix

Species and instar of mites commonly phoretic on adult long-homed beetles associated with southern pines.

Order Parasitiformes

Suborder Gamasida

Superfamily Ascoidea

Family Ascidae-adult females phoretic

Mucroseius monochami Lindquist 1%2

Superfamily Rhodacaroidea

Family Digamasellidae-deutonymphs phoretic

Dendrolaelaps varzpunctutus (Hurlbutt 1967)

Lkndrokzefups isodentatus (Hurlbutt 1967)

Dendrolaelaps neodisetus (Hurlbutt 1%7)

Longoseius cuniculus Chant 1961

Superfamily Uropodoidea-deutonymphs phoretic

Family Uropodidae

ZRichouropoda lamellosa Hirschmann 1972

l?ichouropoda australis Hirschmann 1972

IIPichouropoda hirsuta Hirschmann 1972

Order Acariformes

Suborder Actinedida

Superfamily Cheyletoidea

Family Cheyletidae-adult females phoretic

Eutogenes vicinus Summers and Price 1970

Superfamily ‘Brrsonemoidea

Family Thrsonemidae-adult females phoretic

Tarsonemus subcorticalis Lindquist 1%9

Superfamily “Ikombidioidea

Family Neotrombididae-larvae parasitic

Neotrombidium tricuspidum Borland 1956

Suborder Acaridida

Superfamily Acaroidea

Family Acaridaedeutonymphs (hypopodes)

phoretic

Histiogaster arborsignis Woodring 1963

Superfamily Anoetoidea

Family Histiostomatidae4eutonymphs

(hypopodes) phoretic

Histio.vtoma varia (Woodring and Moser 1970)

Super family Anoetoidea

Family Histiostomatidae-deutonymphs

(hypopodes) phoretic

Hktiostoma vati ( Woodring and Moser 1970)

a