The Cleptoparasitic Bee Tribe Rhathymini (Hymenoptera: Apidae): Description of a New Genus and a Tribal Review

2004·5.4 MB·English

by  Michael S Engel

HYM. RES.
J.
Vol. 13(1), 2004, pp. 1-12
The Cleptoparasitic Bee Tribe Rhathymini (Hymenoptera: Apidae):
Description of a New Genus and a Tribal Review
Michael S. Engel, Charles D. Michener, and Molly G. Rightmyer
Division of Entomology, Natural History Museum, and Entomology Program, Department of
Ecology and Evolutionary Biology, Snow Hall, 1460 Jayhawk Boulevard, University of Kansas,
Lawrence, Kansas 66045-7523, USA
—
Abstract. The new genus Rhathymodes is proposed for Rhathymus acutiventris Friese [with its
new synonym, R. fiiesei Ducke], and R. bertonii Schrottky; resulting in the new combinations:
Rhathymodes acutiventris (Friese) and R. bertonii (Schrottky). A lectotype is newly designated for
R. friesei. To accommodate the new genus, changes are suggested for a key to subfamilies and
tribes ofApidae. The tribe Rhathymini and its twogenera arecharacterized, asarethetwospecies
of Rhathymodes.
The neotropical cleptoparasitic apine Engel (2001); equivalents are indicated in
tribe Rhathymini consists of moderate brackets in keys and descriptions. The ab-
mm
sized to large (13-28 body length) breviations T and S are for metasomal ter-
species superficially resembling vespid ga and sterna; T3, for example, is the third
wasps, especially Polistes, or suggesting in metasomal tergum. Antennal flagellarseg-
form giant species of the bee genus No- ment is abbreviated F. Photomicrography
mada. The impetus for the present paper was done using a Microptics ML-1000
was the discovery by Martin Cooper of Digital Imaging System.
Lyme Regis, U.K., and almost simulta- Collections in which specimens are pre-
neously by one of us (MSE), that some of served are indicated by names of cities or
the smaller species hitherto placed in towns in brackets, with names of relevant
Rhathymus do not run to the Rhathymini curators in parentheses, as below:
in the key to the subfamilies and tribes of [Berlin] Museum fur Naturkunde,
Apinae by Michener (2000: 571-574). Berlin, Germany (Frank
These smaller species represent a second Koch).
genus of the, until now monogeneric, [Budapest] Hungarian Natural His-
Rhathymini. It is a genus with some prob- tory Museum, Budapest,
able plesiomorphies relative to Rhathymus Hungary (Lajos Zambon).
and therefore likely to provide some in- [Chamela] Instituto de Biologia,
sight into relations between Rhathymini Universidad Nacional
and other tribes of Apinae. We hope that Autonoma de Mexico, re-
recognition of the new genus, named be- search station at Chame-
low Rhathymodes, will encourage the dis- la, Jalisco, Mexico (Ricar-
covery ofits unknown hosts, and ofits lar- do Ayala).
val characteristics. [Heredia] Instituto Nacional de Bio-
The morphological terminology used diversidad (InBio), Here-
below follows that of Michener (2000) dia, Costa Rica (Carolina
with some modifications as proposed by Godoy).
Journal of Hymenoptera Research
Figs. 1-2. Khathymodesbertonii(Schrottky). 1,Dorsalhabitus. 2,Lateralviewofhead,mesosoma,andanterior
metasoma (note absence of pleural tubercle).
[Lawrence] = Division of Entomology, [New York] = American Museum of
University of Kansas Nat- Natural History, New
ural History Museum and York, New York, USA (Je-
Biodiversity Research rome G. Rozen, Jr.).
Center, Lawrence, Kan- [San Lorenzo]= Museo Nacional de His-
sas, USA. toria Natural del Para-
[Lyme Regis]= Martin Cooper collection; guay, San Lorenzo, Para-
UK
Lyme Regis, (Martin guay (Bolivar R. Garcete-
Cooper). Barrett).
Volume 13, Number 1, 2004
SYSTEMATICS than distance from apex to wing tip, apex
Tribe Rhathymini Lepeletier rounded and separated from costal wing
margin; pterostigma one-fourth to one-
BJw.thymites Lepeletier 1841: 539. Type genus: fifth as long as marginal cell, border of
Khathymus Lepeletierand Serville 1828.Com- pterostigma in that cell straight or gently
bining stem:—Rhathym—. concave; wing hairy, alar papillae absent
Description. Body usually without are- (Fig. 4). Hind wing with cu-a [cu-v]
as of dense pale appressed pubescence; oblique, longer toMslightly shorter than
form elongate, pubescence short, so that second abscissa of +Cu; jugal lobe mi-
habitus suggests Polistes wasps or giant nute, rounded, about one-tenth as long as
Nomada (e.g., Fig. 1); coloration black to vannal lobe. Metasoma widest at T2 and
largely yellow, sometimes with metasoma T3; Tl markedly narrower than T2, lateral
red, or all red. Compound eyes slightlydi- profile slanting, dorsal surface only weak-
verging below. Clypeus protuberant to ly differentiated and less than half as long
less than width ofcompound eye in lateral as slanting, more anterior, surface. T7 of
view because lower part ofcompound eye male tapering to bidentate apex, without
quite broad. Mandible slender, simple. La- pygidial plate; S4, S5, and sometimes S3
brum as long as or longer than median of male strongly fringed; S7, S8, and male
length of clypeus. Proboscis long, in re- genitalia as illustrated (Figs. 6-13), geni-
pose reaching between or to apices ofpro- talia with both upper and lower gonosty-
coxae; labial palpus with first two seg- lar processes well developed, upper rather
ments subequal in length, last two seg- slender with branched hairs, lower broad
ments minute, directed laterally; maxillary and translucent; penis valve heavily scler-
palpus absent. Antennal scape short, less otized, spatha largely membranous but
than three times as long as wide; Fl about with heavily sclerotized longitudinal bar
half as long as F2. Epistomal sulcus absent at each side. Female without pseudopy-
below anterior tentorial pits so that clyp- gidial area; pygidial plate present, taper-
eus and lower paraocular areas are fused. ing to apical narrowly rounded point, lat-
Lateral ocellus separated from median eral margins weakly concave to weakly
ocellus by one-third ocellar diameter or convex. Sting well developed; gonoplac
less; preoccipital area rounded. Scutellum [= gonostylus] long, slender, parallel-sid-
grading from somewhat elevated to form ed. —
transverse shining ridge to distinctly bi- Comments. Some of the characteristics
tuberculate, posterior declivitous part lon- used to identify the Rhathymini by Mich-
ger, sometimes much longer, than anterior ener (2000) turn out to be generic charac-
subhorizontal part; axilla small, rounded, ters of Rhathymus rather than tribal fea-
not produced to form tooth. Propodeal tri- tures. The key to subfamilies and tribes of
angle hairy. Procoxa tapering, mesal api- Apidae (Michener 2000: 572) should be
cal margin produced as flattened hairy changed so that couplet 17 omits the
process that looks like slender hairy spine phrases about the mesepisternal tuber-
in ventral view (Fig. 5). Protibia and me- cle. Furthermore, because ofprobablecon-
sotibia each with distinct outer apical fusion at couplet 16, Rhathymini should
spine; tibial spurs unmodified. Claws each run out not only at couplet 17 but also
with flattened basal tooth; arolia present. through couplet 20. Change the outcome
Scopa absent. Forewing with three sub- of the second alternative of couplet 20 to
marginal cells; marginal cell large, longer 20a and add a new couplet as follows:
Journalof Hymenoptera Research
20a (20). Maxillary palpus absent and axilla small, not at all produced; epistomal sulcus ab-
sent below anterior tentorial pit so that clypeus and lower paraocular areas are
fused Apinae, Rhathymini
Maxillary palpus present, or ifabsent, then axilla produced to point {Odyneropsis in
Epeolini); epistomal sulcus usually complete 21
KEY TO GENERA OF RHATHYMINI
Mesepisternum with large submedian tubercle; vein cu-a [cu-v] of hind wing strongly
oblique and distinctly longer than second abscissa ofM+Cu; supraclypeal area strongly
elevated, crested medially, not continuing convexity of clypeus; ocellocular area de-
pressed below level of adjacent areas Rhathymus Lepeletier and Serville
Mesepisternum without tubercle; vein cu-a [cu-v] of hind wing less strongly oblique and
slightly shorter than or subequal to second abscissa of M+Cu; supraclypeal area with
surface generally a continuation of convexity of clypeus although with small frontal
tubercle at lower end of frontal line; ocellocular area not depressed
Rhathymodes Engel, Michener, and Rightmyer
—
Genus Rhathymus Lepeletier and Diagnosis. The principal characters of
Serville this genus are included as contrastingpar-
Figs. 6, 7, 10, 11 enthetical notations in the description of
Rhathymodes,—below.
ColaxLepeletierandServille1825:4,213. Nomen Comments. The name Bureauella was
nudum.
synonymized by Michener (2000: 739). Its
Rhathymus Lepeletier and Serville 1828: 448. type species, briefly described by Domi-
Type species: Rhathymus bicolor Lepeletier was
a18n4d1: S5e3r9v.illDeall1a82T8o,rrmeon1o89b6a:si3c2.3. LMeipcelheetnieerr nwiiqtuheda(r1k898m)e,tasomavlerbyandlsar.geI,t iyseallpoowsissih-
2000: 739. Silveira et al. 2002: 129. ble senior synonym ofRhathymusversicolor
Colax Lepeletier and Serville 1828: 448. Nomen Friese 1906. Friese (1912) gave a key to the
praeoccupatum [nee Hubner 1819 (Lepidop- species, including species now placed in
tera); Wiedemann 1824 (Diptera);etStephens Rhathymodes and in the genus Odyneropsis
1829 (Hymenoptera)]. Type species: Rhathy- of the Epeolini. About 16 species-group
mus bicolor Lepeletier and Serville 1828, names have been proposed for Rhathymus
monobasic. Established as a synonym of but the actual number of species is prob-
Rhathymus Lepeletier and Serville 1828 and ably smaller; the genus is in need of re-
t11h.e6r)e;fosreee anlosot Maivcahielnabelre(1(9I97C)Z.N 1999: Art. visBiioonloagnyd.—cSoompfraerheanssikvneowcnla,disRthiactshtyumduys.
LiomgausstrabiPceorltory 1L8e3p3e:le1t4i6e.rTyapnedspSeecriveisl:leRha1t8h2y8-, species are cleptoparasites of Epicharis
monobasic. (Apidae: Centridini), apparently deposit-
Rathymus Smith 1854: 278. Lapsus calami et ing their eggs through a small opening in
praeoccupatum [nee Dejean 1831 (Coleoptera), the host's brood-cell closure (Camargo et
et Gistel 1848 (Echinodermata)]. al. 1975; Hiller and Wittmarm 1994- Rozen
Bureauella Dominique 1898: 61. Type species: 1969, 1991, 2003). The hospicidal, first in-
Bureauella insignis Dominique 1898, mono- star dispatches the host larva before feed-
basic. ing on the provisions (Rozen 1969, 1991).
Volume 13, Number 1, 2004
Figs. 3-5. Rhathymodes bertonii (Schrottky). 3, Frontal view of head. 4, Forewing. 5, Ventral-oblique view of
head and mesosoma; arrow indicates short, setose extension ofprocoxa (note absence ofpleural tubercle).
Journalof Hymenoptera Research
Larval stages were described by Rozen gins weakly concave, meeting apically to
(1969, 1991), McGinley (1981), and Camar- form translucent apex of T6 (margins
go et al. (1975) who also described the straight or weakly convex, apex of T6
pupa. Rozen (2000, 2001) gave additional opaque and largely formed by extension
characters for distinguishing the mature of elevated discal part of pygidial plate).
larva and pupa of Rhathymus and Rozen 9. Apical process of second valvifer of fe-
(2003) described the eggs (as mature oo- male forming slender hook above base of
cytes) of two species. Raw (1991, 1992) gonoplac [= gonostylus] (more robustand
gave an account of the post-emergence not hooked). 10. Male S4 and S5 simple,
flight behavior of male Rhathymus as well transverse, exposed surfaces as long as
as some host data. those of adjacent sterna (male S4 and S5
much shortened me-
broadly emarginate,
Rhathymodes Engeln,ewMichener, and dially so that only narrow margins are ex-
Rightmyer, genus posed, thus exposed part of S6 large). 11.
Figs.—1-5, 8, 9, 12, 13 Lateral extremities of male S5 not pro-
Type species. Rhathymus acutiventris duced (strongly produced posterolaterally
Friese 1906.— and hairy, supporting hair tuft noticeable
Diagnosis. The generic characters are from above, see Michener 2000: fig. 102-
listed below, each followed by the state of 2). 12. Male S3-S5 with apical fringes of
the same character in Rhathymus, in paren- erect, curved or sigmoid hairs (fringes ap-
mm mm
theses. Body length 13-18 (16-28 pressed, not conspicuous, well developed
in Rhathymus). 1. Supraclypeal-frontalarea only on S4 and S5). 13. Genitalia and hid-
convex, in profile continuing convexity of den sterna as in figures 8-9, 12-13 (cf.
clypeus, frontal tubercle and carina above Figs. 6-7, 10-11 for Rhathymus); lateral
it rather weak, see figures 2-3 (this area sclerotization of spatha arcuate and pro-
strongly produced as crest, in profile ele- duced (not arcuate,—not produced).
vated above imaginary continuation of Included species. Three names have
clypeal convexity, sloping steeply at sides been provided for species of Rhathymodes,
into depressions around antennal bases). as follows: Rhathymodes acutiventris
2. Ocellocular area notdepressed (strongly (Friese), R. friesei (Ducke), and R. bertonii
depressed below level of adjacent areas). (Schrottky). All are new combinations
3. Scutellum bituberculate, the two con- and, as indicated below, the first two are
vexities (sometimes weak) forming line subjective syn—onyms.
between dorsal and posterior declivitous Etymology. The new genus-group
surfaces (with shining ridge, sometimes name is a combination of Rhathymus (Gr.
depressed medially to form weak bituber- rhathymos, meaning "carefree" or "lazy")
culation, on line between dorsal and de- and the suffix -odes (Gr., an adjectival de-
clivitous surfaces). 4. Mesepisternum rivative of eidos, meaning "resembling").
without anteromedian tubercle (with The gender is—masculine.
large, mostly impunctate and hairless, an- Distribution. Jalisco, Mexico, to Para-
teromedian tubercle). 5. Mesobasitarsus guay, essentially the same as—for Rhathymus.
shorter than mesotibia (as long as meso- Phylogenetic commentary. Comparison
tibia). 6. Forewing with second submar- with other tribes of Apinae suggests that
ginal cell receiving lm-cu [= first recur- characters 1, 2, 4, 10, and 11 are plesiom-
rent vein] near middle or distal third, see orphic relative to Rhathymus. Perhaps
figure 4 (near apex of cell). 7. Hind wing characters 3 and more certainly 9 and the
with cu-a [c-v] subeMq+uaCluto or shorter than spatha in 13 are derived (admittedly, the
second abscissa of (longer than). 8. sting and male genitalia are unknown in
Pygidial plate of female with lateral mar- R. bertonii).
Volume 13, Number 1, 2004
KEY TO SPECIES OF RHATHYMODES
(based on females only)
1 Mandible longer than minimum distance between compound eyes; third submarginal cell
as long as to longer than second submarginal cell; mesoscutal surface with four yellow
stripes; propodeum yellow with black, median, longitudinal stripe on posterior surface
(narrowerand slightly fainterinspecimens from Nicaragua);metasoma yellowordusky
yellow R. acutiventris (Friese)
- Mandible shorter than minimum distance between compound eyes (Fig. 3); third submar-
ginal cell markedly shorter than other submarginal cells (Fig. 4); mesoscutal surface
appearing yellow with two black stripes (Figs. 1, 3); propodeum yellow withoutblack,
median, longitudinal stripe (Fig. 1); metasoma mostly black (Figs. 1-2)
R. bertotiii (Schrottky)
Rhathymodes acutiventris (Friese), rior mesoscutal margin, submedian bands
new combination sometimes partly fused; pretarsal claws;
Figs. 8-9, 12-13 longitudinal median stripe on posterior
Rhathymus acutiventris Friese 1906: 120. Friese surface of propodeum; apex of pygidial
1912: 226. Holotype [Budapest], examined. plate (sometimes brown rather than
Rhathymusfriesei Ducke 1907: 458. Friese 1912: black). Ventral surface of flagellum yel-
225. Silveira et al. 2002: 129. Lectotype [Ber- low-brown except yellow Fl. Tibial spurs
lin], examined. New synonym. dark brown. Metasomal terga sometimes
—
Description. Body length 13-18 mm. dusky yellow with lighter yellow apical
Mandible of female longer than minimum bands, although usually uniformly yel-
cdeilsltamnecaesbuertewdeeonn epyoesst.erTihoirrdmasrugbimnarngeianrally laonwd.pWtiernogsstitgrmaansdpaarrkenbtrobrwonwntiosbhl,acvkeiisnh.s
as long as to longer than second. Bodyand Pubescence golden, short except on distal
legs yellow (sometimes brownish yellow), part of labrum (where it forms two tufts),
the following areas black or blackish: api- genal area, sides of mesosoma and pro-
cal half of mandible; labrum except for podeum; pubescence of mesoscutum of
two brownish spots near base; subanten- rather uniform length, shorter than ocellar
nal sulci and epistomal sulcus between diameter, erect; pubescence of metasomal
anterior tentorial pits; upper surface ofan- terga appressed, appearing dark against
tenna (sometimes brownish) except some- yellow background. Punctation fine and
times yellow or yellow-brown onbase and dense so that most surfaces are dull but
apex of flagellum; ocellar area extending labrum, clypeus (especially impunctate
down on either side of supraclypeal ele- lower margin), pronotal lobe and hypoe-
vation to antennal bases and usually ex- pimeral area shining because punctures
tending laterally on occiput behind sum- less dense; metasomal terga especially
mit of compound eye; transverse spots on uniformly dull because of fine punctua-
anterior surface of pronotum; spot at an- tion and dense short hair. Male hidden
terior base of pronotal lobe; mesoscutum sterna and g—enitalia as in Figs. 8-9, 12-13.
except for lateral marginal yellow band, Variation. Because of variation in scu-
broadened anteriorly, and submedian lon- tellar form we at first believed that the
gitudinal yellow band, thus four yellow specimens here placed in R. acutiventris
bands on mesoscutum, none of them at- represented two or more species. Fre-
taining anterior and posterior mesoscutal quently the convexities are prominent so
margins or lateral bands attaining poste- that the declivitous surface below their
Journalof Hymenoptera Research
F7a,iegdsLe.aat6ge-ur7as.l;vcRie=hwa.tuhpLypemeturtsergsboincsooeclroovrxeiLtetepo;elidentd=iiecrautpaepneidrdeSngetorivncioalslltey,sltmararuclpteruorgceeesnsists;aeleeina.=i6n,lodViwefenfrterrgaeonlnto(lsvetifyte)lwaasrn(dpardo=ocresspsae;lnif(sr=ivgahstlp)vaevt;hiaeb)w.s=.
summits is about one and one half times Mexico and Honduras and find no differ-
as long as the dorsal surface (seen in lat- ences between them.—
eral view). Less commonly the convexities Material examined. MEXICO: Jalisco:
are smaller. Thus, in a specimen from Su- 19, Chamela, 13 July 1990 (R. Ayala)
N
riname the declivitous surface is more [Chamela]. Chiapas: 16, Agua Azul, of
than twice as long as the dorsal surface Ocosingo, 23 April 1993 (F. Noguera)
and this condition is approached in a [Lawrence]; 19, Parque Laguna Belgica,
specimen from Cerro Campana, Panama, 19.3 km N of Ocozocoautla, 1560 m, 12
although another collected on the same June 1991 (J. Ashe) [Lawrence]. GUATE-
day had larger convexities. From the few MALA: 19, Zarapa, 3.5 km SE of La
specimens available we see no geograph- Union, 1500 m, 23 Jun. 1993 (J. Ashe, R.
ical significance in the scutellar variation. Brooks) [Lawrence]. HONDURAS:Atlan-
It would have been desirable to examine tida: 19, Lancetilla Botanical Garden,
male terminalia from all parts of the range Tela, 10 m, 15°46'N, 87°27'W, 22 June 1994
but males are available only from south- (J. Ashe, R. Brooks, methyl salicylate and
ern Mexico, Honduras, and Panama; we eucalyptus oil attractants) [Lawrence].
have made dissections of specimens from Cortez: 36, 39, Parque Nacional Cerro
Volume 13, Number 1, 2004
Figs. 8-11. Maleinternal sterna. 8-9,Khathymodesacutiventris (Friese):8,Eighthsternum.9,Seventhsternum.
10-11, Rhathyinus bicolor Lepeletierand Serville: 10, Eighth sternum. 11, Seventh sternum.
Azul-Meambar, Los Pinos, 800 m, 1995 (J. Ashe, R. Brooks) [Lawrence]. Co-
14°42.4'N, 87°54.7'W, 10-16 May 2002 (S. lon: 39, 14 km N of junction of Escobal
Peck) [Lawrence]. NICARAGUA: Grana- and Pina roads, 30 m, 2 June 1996 (J. Ashe,
da: 39, Volcan Mombacho, Santa Ana 2, R. Brooks) [Lawrence]; 26, Barro Colora-
15 May 1998, malaise trap (J. M. Maes) do Island, 29 May 1977 (R. B. & L. S. Kim-
[Lawrence]. 1 9, Volcan Mombacho, Santa sey) [Lawrence]. SURINAME: Brokopon-
Ana 2, 21 June 1998, malaise trap (J. M. do: 19, Brownsberg Nature Preserve, Witi
Maes) [Lawrence]. COSTA RICA: Alajue- Creek Trail, 80 m, 4°56'55"N, 55°10'53"W,
la: 19, Cano Negro, 20 m, 10-19 March 23-25 June 1999 (Z. Falin, A. Gandadin, H.
1993 (K. Martinez) [Heredia]. Gnanacaste: Hiwat) [Lawrence]. BRAZIL: Para: 16,
19, Maritza Biological Station, 550 m, 22 Estado do Para, Vbidos (Rio Branco),
May 1993 (J. & A. Ashe) [Lawrence]. 19, VIII.1912, Ducke [Berlin]. Pernambuco:
Parque Nacional Guanacaste, Est. Pitilla, 9 19, Caruaru, 900 m, April 1972 (M. Al-
km S of Est. Cecilia, 700 m, 19 May-3 June varenga) [New York]. Minas Gerais: 16,
1993 (P. Rios) [Heredia]. Puntarenas: 19, Barbacena, 14.12.1905, Ducke [lectotype of
Fila Moras, Buenos Aires, A. C. Amistad, R. friesei, Berlin, see below]. Sao Paulo or
1000m, 19 May 1993 (M. A. Zumbado, S. Parana: 16, Rio Parana, Siid-Brasil, 1904
Rojas) [Heredia]. PANAMA: Chiriqni: 19 [description and photograph, Friese 1912:
[type of R. acutiventris, in Budapest, ex- 225, examined, Berlin]. —
amined]. Panama: 29, Cerro Campana Lectotype designation. Several speci-
(Capira), 825 m, 8°44'N, 79°57'W, 1-5 June mens of R. friesei are located in the Friese
Journalof Hymenoptera Research
10
Figs. 12-13. Rhathymodes acutiventris (Friese), male genitalia. 12, Ventral (left) and dorsal (right) views. 13,
Lateral view. Lettering as in Figs. 6-7.
—
collection [Berlin] and manybear his char- Comments. Just over half of the speci-
acteristic "typus" labels. As is unfortu- mens were collected by flight intercept
nately not rare for specimensbearing such traps set up in forests. Frequently used by
labels, many are not part of the original coleopterists, such traps prove tobe useful
type series (e.g., several were collected at in collecting forest bees rarely seen by bee
localities not mentioned in Ducke's origi- collectors.
nal account or, worse yet, were collected
years after the publication of the species!). Rhathymodes bertonii (Schrottky),
new combination
However, among the material is at least
the specimen collected by Ducke at Bar- Figs. 1-5
bmaecnesnameinntiMoinneadsbGyerDauisck(ethaereotnhoetrinspBeecri-- Khathymus bertonii Schrottky 1920: 217. Holo-
type [San Lorenzo], compared.
lin), and this is assuredly one upon which —
he based his description. For the express Diagnosis. Similar to R. acutiventris ex-
purpose of nomenclatural stability we cept as follows: Mandible shorter than
hereby designate and label this individual minimum distance between compound
as lectotype. Lectotype: 16, Brazil, Estado eyes (Fig. 3), suggesting mandible of male
de Minas Ger., Barbacena, 14.12.1905, of R. acutiventris. Third submarginal cell
Ducke [Berlin]. markedly shorter than others (Fig. 4). Me-