NOTES ON THE BEHAVIOR AND TAXONOMY OF MEGACHILE (XEROMEGACHILE) BRIMLEYI MITCHELL AND ITS PROBABLE CLEPTOPARASITE, COELIOXYS (XEROCOELIOXYS) GALACTIAE MITCHELL (HYMENOPTERA : MEGACHILIDAE)

4 Pages·1995·1.7 MB·

by  K V Krombein

PROC. ENTOMOL. SOC. WASH.
97(1), 1995, pp. 86-89
NOTES ON THE BEHAVIOR AND TAXONOMY OF
MEGACHILE (XEROMEGACHILE) BRIMLEYI MITCHELL
AND ITS PROBABLE CLEPTOPARASITE,
COELIOXYS (XEROCOELIOXYS) GALACTIAE MITCHELL
(HYMENOPTERA: MEGACHILIDAE)
Karl V. Krombein and Beth B. Norden
Department ofEntomology, Smithsonian Institution, Washington, D.C. 20560.
—
Abstract. Megachile brimleyi Mitchell and its probable cleptoparasite, Coelioxys gal-
actiaeMitchell, werestudiedin southcentral FloridaduringAugust, 1992. Foragingadults
werecollectedalongwithotherbeesandwaspsattractedtotheflowersofGalactiaregularis
and Tephwsia chrysophila. Excavation oftwo active M. brimleyi nests provided details
C
of nest structure and cell construction. Difficulties in keying both female and male
galactiae are discussed, and revised couplets are provided for females.
Key Words: Megachile, nest, Coelioxys, cleptoparasite
A brief visit to the Archbold Biological ile, sandy soil is well drained but moist be-
Station (ABS), Highlands County, Florida, low the surface.
providedanopportunitytoobserveandcol-
Materials and Methods
lect Megachile brimleyi Mitchell and its
probablecleptoparasite, Coelioxysgalactiae Adult bees were collected on plants, and
Mitchell. Bees were collected 14-16 August observed as they excavated nests. Plant
1992, and two active nests were dug up on specimens were put in plastic bags and
the 15th. Plants visited by the bees were transferred later to a plant press. The two
collected and pressed. Voucher insect and bee nestswereexamined afterblowingplas-
plant specimens are deposited in the Na- ter-of-Paris into the nest openings to trace
tional Museum ofNatural History, Smith- their paths, and then carefully removing
sonian Institution (USNM) and the Arch- sand grains from around the tunnels with a
bold Biological Station (ABS). tablespoon, penknife, and small paintbrush.
Nest contentswere preserved in Kahle's so-
Study Site lution, then examined and measured in the
Bees were studied along a firebreak cut- laboratory. The bees were identified using
tingthrough sandpinescrubnearthesouth- Mitchell (1962, 1973) and by comparison
em end ofthe Lake Wales Ridge. This nar- withspecimensidentifiedbyhiminUSNM.
row, north-south ridge ofsandy uplands is
Results and Discussion
part of the ancient line of dunes that re-
mained above water during Pleistocene in- Nest architecture.—Nesting data have
undations. The substrate is composed of been reported for only one other species of
loose, small grained, white quartz sand and the subgenus Xeromegachile, M. rubi
particles of charred organic material, the MitchellinNorthCarolina(Sivik 1954)and
residue from repeated scrub fires. The ster- Georgia (Eickwort et al. 1981). We found
VOLUME 97, NUMBER 87
Table 1. Waspandbee visitors to flowers ofGalactia regularis.
Tiphiidae
Tiphia intermedia Malloch: $.
Larridae
Trypoxylonjohannis Richards: S.
Philanthidae
Cercerislolteca Saussure: S.
Halictidae
Nomia maneeiCockerell: 2 without pollen.
Augochloropsissumptuosa(Smith): 2 without pollen.
Megachilidae
Anthidium maculifronsSmith: 2 without pollen.
Anthidiellum notatum rufimaculatum Schwarz: $.
Megachile(Litomegachile) brevispseudobrevisMitchell: <J, 2 with abundant G. regularispollen on scopa.
Megachile(Litomegachile) mendica mendica Cresson: 3 2, two with abundant G. regularis pollen on scopa,
one with no pollen.
Megachile(Xeromegachile) brimleyi Mitchell: 6, 2 2 without pollen.
Megachile(Xeromegachile) Integra Cresson: 5 ^, 2 2, one female with G. regularispollen on the scopa, one
without.
Coelioxys(Xerocoelioxys)galactiae Mitchell: 2.
M. brimleyifemales digging theirown nests long, and it had not been provisioned or
in sandy soil exposed to full sunlight, sim- capped. Sivik found that M. rubi formed
ilarly to M. rubi. M. brimleyi tunnels were cells of similar size from leaves of Betula
in level ground, and penetrated the sub- lenta, and capped the cells with 4-5 leaf
strate at an angle of45°. The entrances of pieces. Eickwort et al. reported ca 14 leaf
the twoM. brimleyinests were 8.5 and 10.0 pieces used to form a cell, and ca 3 to cap
mm
in diameter. The females used their it.
hindlegstokickthesandgrains3-6cmfrom Plant and insect associations.—Two le-
the nest entrances, thus forming a semicir- guminous plants, the pink-flowered Galac-
cular spoil heap. Both tunnels were 10 cm tia regularis, and the white-flowered, pros-
long, and ended in an enlarged chamber, a trate Tephrosia chrysophylla, attracted a
single cell. It was our impression that these varietyofwaspsandbees(Tables 1, 2). Both
nests, the only two found in the area, were sexes ofMegachile brimleyi visited flowers
newly initiated, and eventually might have ofboth plants, and one nesting female car-
contained more cells. Sivik reported that ried G. regularis pollen on the scopa. Inter-
nests of M. rubi had 1-3 cells in a linear estingly, females o{Coelioxysgalactiaealso
series,while 1-4cellswerereportedbyEick- visited both plants. Behavioral data strong-
wort et al. ly suggest that C. galactiae is a cleptopar-
Thecell ofoneM. brimleyinestwaslined asite of M. brimleyi. We watched two fe-
with 1 1 leaf pieces cut from Galactia re- males of C. galactiae each following a M.
mm
gularis. Eight of the pieces were ca 9 brimleyi female, and then entering her nest
wideand 15.5 mmlongwithroundededges. afterher. We also observed other Coelioxys
Three subcircular pieces, used to form the females, presumablygalactiae, followingM.
mm mm
cell base, were ca 7 wide and 8 brimleyi females as they flew over the sand
long. The leaf cuttings were weakly ce- and among the plants.
mm
mented together. The cell was ca 17 MegachileIntegraCressonistheonlyoth-
PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
Table 2. Bee visitors to flowersofTephrosiachry- Weexaminedtheseriesofthesethreespe-
sophylla. (No wasps were noted on this plant.) cies in the National Museum of Natural
History (USNM), and the syntypes of C.
Halictidae
galactiaein thecollectionatNorthCarolina
Nomia maneeiCockerell: 3 9, one with abundant State University. We believe that the fol-
T. chrysophylla pollen on the scopa, others with
lowing key will distinguish the three taxa
lesseramounts.
withgreatercertainty. Itshouldreplacecou-
Megachilidae
plets 13 and 14 in Mitchell (1962).
Megachile(Xeromegachile) hrimleyiMitchell: S, $
withoutpollen.
Coelioxys(Xerocoelioxys)galactiaeMitchell: 2 9. 13. Carina on pronotal lobe strongly raised, la-
mellate; vestiture of head short, appressed,
denseonclypeusandlowerfront;thoraxwith
areasofshort,dense,appressedwhitesetae-
narrow bands anteriorly and posteriorly on
er Xeromegachile that we collected at the scutum, narrow anterior band on scutellum
studysite. Both sexeswerecollectedon Gal- sometimesinterruptedmediallyand thepos-
actia flowers, but only one female had nu- teriordeclivous surface, small median patch
onmetanotum,narrowanteriorandposterior
merouspollengrainsofGalactiaonthesco- bands on mesopleuron; clypeus slightly con-
pa. Nothing is known ofthe nesting habits vex, notelevatedabove level offace
ofM. Integra. C galactiaeMitchell
Carinaon pronotal lobe not raised, obscured
Coelioxys galactiae Mitchell by vestiture in C. sodalis; vestiture ofhead
Fig. 2 appressed and not so dense on clypeus and
supraclypealarea only; thoraxeitherwithout
The syntype series ofC. galactiaeis from appressedsetae,orwithsuchareasgreatlyre-
North Carolina, Illinois, and northern Flor- duced in extent; clypeus slightly convex or
ida (Clay and Levy counties). Both sexes elevated 14
have light red legs except for the coxae. 14. Clypeus slightly convex, not elevated above
levelofface;vestitureofhead,exceptclypeus
However, ninefemalesand fourmalesfrom and supraclypeal area, and thorax long, erect
ABS in south central Florida have the legs and silvery C. sodalisCresson
predominantly black or dark brown except Clypeusmorestronglyconvex,elevatedabove
for two females which have reddish brown level of face as viewed in profile; vestiture
tibiae and tarsi. This is a striking reversal appressed on clypeus and supraclypeal area,
suberectlaterallyalongorbitanderectonup-
of the normal coloration of aculeate Hy-
perfront, shorterthan in C. sodalis; bandsof
menoptera in which there is an increasing appressed,decumbenthaironscutum absent
amount of red in more southern popula- anteriorly, evanescent laterally and posteri-
tions. orly; appressed setae on scutellum forminga
Mitchell (1962) separated femalesofthree narroweranterior band than in C. galactiae,
sparseron posteriordeclivoussurface; meta-
species ofCoelioxys, galactiae Mitchell, so- notum with longer, suberect, evenly distrib-
dalis Cresson and immaculata Cockerell, uted setae; mesopleuron with narrower an-
from the other eastern species ofthe genus teriorandposteriorbandsoflonger, suberect
by the similarly shaped sixth sternum. It is setae C. immaculata Cockerell
not notched laterally but is incurved api-
C
cally to form a short, acute, subtriangular Floridian males of galactiae key to C.
C
projection. Females of galactiae from boharti Mitchell (Mitchell 1962) because of
ABS do not key out properly in Mitchell their dark legs. We examined the unique
C
(1962, couplets 13-14). In a series of nine holotype of boharti (USNM), and find
females from ABS the tibiae and tarsi are that it is readily distinguished by the abun-
predominantly black or dark brown in sev- dant, broad, short setae on the mesopleural
en, reddish brown in two. disk, 2-3 times as long as wide, the more
)
VOLUME NUMBER 89
97, 1
Acknowledgments
1 We are grateful to personnel at the Arch-
bold Biological Station fortheirhospitality,
We
and for providing laboratory facilities.
are indebted to Alan Hemdon, Florida In-
ternational University, Miami, for identi-
0.25mm
fication ofplants during our stay at the Sta-
tion. We thank R. L. Blinn, Department of
Entomology, North Carolina State Univer-
sity, fortheloanofthesyntypeso^Coelioxys
We
galactiaeMitchell in that collection. are
grateful to George Venable, Department of
Entomology, SI, for preparing the illustra-
tions. We also appreciate the assistance of
Arnold W. Norden in the collecting ofbees
and waspsatABS. We thank S. W. T. Batra
merFieg,s.lat1,era2.l asCpoeeclti,oxveynstrsaplecimeasr,gianpicaatlbhoatltfomo.fp1a,rCa- and J. Cane for reviewing the manuscript.
boharti Mitchell; 2, C. galactiaeMitchell. Literature Cited
Eickwort, G. C, R. W. Matthews, and J. Carpenter.
1981. Observations on the nesting behavior of
infuscated wings, and the paramere (Fig. 1 Megachile ruhi and M. texana with a discussion
which in lateral view widens gradually for ofthe significance ofsoil nestingin theevolution
most of the apical half, and then tapers ofmegachilidbees(Hymenoptera: Megachilidae).
obliquely to the narrowly rounded apex. In Journal ofthe Kansas Entomological Society 54:
C. galactiae the discal setae of the meso- 557-570.
Mitchell, T. B. 1962. Megachilidae, pp. 5-232. In
pleuronarenarrower,mostlymorethanfour BeesoftheEasternUnitedStates,vol.2.Technical
times as long as wide, and the apical halfof Bulletin 152, North Carolina Agricultural Exper-
theparamere(Fig. 2), inlateralview,widens iment Station.
gradually over most of its length with the . 1973. A subgeneric revision ofthe bees of
apex broadly rounded. The discal vestiture the genus Coelioxys ofthe Western Hemisphere.
DepartmentofEntomology,NorthCarolinaState
ofthe mesopleuron is variable in width in University, Raleigh, 129 pp.
specimensfromABS,butitisneverasbroad Sivik,F.P. 1954. Ecologicalnotesonthethreespecies
and short as in C. boharti. ofsolitarybees.EntomologicalNews65:253-256.