Oocytes, Larvae, and Cleptoparasitic Behavior of Biastes Emarginatus (Hymenoptera: Apidae: Nomadinae: Biastini)

PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024 Number 3667, 15 pp., 30 figures, 1 table November 30, 2009

Oocytes, Larvae, and Cleptoparasitic Behavior of Biastes emarginatus (Hymenoptera: Apidae: Nomadinae: Biastini)

JEROME G. ROZEN, JR.,1 JAKUB STRAKA,2 AND KATERINA REZKOVA2

ABSTRACT We present information on the nest-searching and parasitic behavior of the European cleptoparasitic bee Biastes emarginatus (Schenck), found attacking nests of Rophites quinquespi- nosus Spinola in the Czech Republic. Its mature oocyte, first instar, and last larval instar are described and illustrated by SEM micrographs, microphotographs, and diagrams. These stages are compared with those of other members of the Biastini. Because the first instar of the related Neopasites cressoni had not been described before, its description is appended, so that comparisons can be made with B. emarginatus. In most respects, the biology and immature stages of B. emarginatus closely resemble what is known concerning other tribal members, but we note that the mature larva, though agreeing morphologically with those of close relatives, has an anatomy that invites investigation into adaptive function.

INTRODUCTION genera totalling12 named species is restricted to the Holarctic region, with Neopasites and This study reports on the biology and imma- Rhopalolemma in North America and Biastes ture stages of the cleptoparasitic bee Biastes in the Palearctic (Michener, 2007). Known emarginatus (Schenck) and compares the infor- hosts of all biastines belong to the Rophitinae mation with existing knowledge concerning (Halictidae), as follows (host names in parenthe- other members of the Biastini, one of the ses): Neopasites (Dufourea), Rhopalolemma numerous tribes of the Nomadinae, all of which (Protodufourea), Biastes (Systropha, Rophites, are cleptoparasites. This small tribe of three and Dufourea) (Michener, 2007; Westrich, 1989).

1 Division of Invertebrate Zoology, American Museum of Natural History ([email protected]). 2 Faculty of Science, Charles University in Prague, Department of Zoology, Vinicˇna´ 7, 128 44 Praha 2, Czech Republic ([email protected]).

Copyright E American Museum of Natural History 2009 ISSN 0003-0082 2 AMERICAN MUSEUM NOVITATES NO. 3667

Beyond host associations, biological infor- Miller), but much of the area received consid- mation concerning these cleptoparasitic gen- erable sunlight during a large part of sunny era is limited. Torchio et al. (1967) described days.Groundcover,mostlytallgrasses(ca host-searching behavior of adults, the eggs, 30 cm high), obscured much of the surface, so egg-laying habits, and larval behavior of that many nest entrances were partly or Neopasites cressoni Crawford. Rozen et al. completely hidden. Nest entrances, surrounded (1997) reported on various aspects of the by tumuli when fresh, were left opened during biology of Rhopalolemma rotundiceps Roig- foraging. The main burrows of host nests Alsina. However, details concerning the biol- descended vertically with sharp turns to avoid ogy of Biastes have been lacking. rocks. Cells in a nest were arranged singly (i.e., The immature stages of these three genera not in linear series). Scattered nests were found have been examined on a number of occasions. a few meters away from the main site, but Egg/mature oocytes of exemplars of all genera activity of B. emarginatus was low there. At have been described. Most of these descriptions least 10 Biastes females flew over the main part were accompanied by information concerning of the nest aggregation during the peak of the number of ovarioles per ovary found in activity on sunny days. dissections because among the Nomadinae there The aggregation was studied during 3–18 is extensive variation in ovariole counts from August 2008. Rophites females were active one species to the next. Egg/oocyte descriptions from early morning to late afternoon, flying are as follows: Neopasites cressoni (Torchio et even when the sky was overcast. In contrast, al., 1967; Rozen et al., 1997); Rhopalolemma flight activity of Biastes depended on weather rotundiceps (Rozen et. al., 1997); Biastes brevi- conditions. They flew only during warm, cornis (Panzer) (Rozen and O¨ zbek, 2003). sunny, windless days (temperatures 25–30uC), Information concerning ovary statistics is sum- and on such days they preferred host nests marized in Rozen (2003). Descriptions of first situated in sunny places. In addition, search- instars of the Biastini have been lacking until ing Biastes females moved with the sunny now. Because we describe here the first instar of areas as these areas shifted during the day. Biastes emarginatus, we append a comparative Only during the warmest days, when the account of the first instar of N. cressoni.Mature temperature rose over 30uC, did Biastes biastine larvae have been described, as follows: females prefer shaded parts of the nesting site. N. cressoni (Rozen, 1966, 1996a; McGinley, When the temperature fell below 25uC, the 1981) and R. rotundiceps (Rozen et al., 1997). bees flew strictly in shafts of sunlight or were An intermediate stage larva of Biastes emargi- inactive, behaving similarly to the thermoph- natus was treated by Rozen (1993), as was the ilous behavior of another cleptoparasitic bee pupa of N. cressoni (Rozen, 1997). Epeoloides coecutiens (Fabricius) (Straka and Bogusch, 2007a). Because the site was com- BIOLOGICAL OBSERVATIONS pletely shaded in the morning and late afternoon, Biastes females were active only J.S. and K.R. made the following observa- from 10:30 A.M. to 4:00–5:00 P.M. (CEST). tions on Biastes emarginatus at a dense nest- While searching Biastes females usually flew ing aggregation of Rophites quinquespinosus slowly close to the vegetation, scanning the Spinola in a large, unattended garden in ground surface for host nests. Because nests Praha-Misˇkovice, a district of Prague, Czech were often well hidden in the grass, Biastes Republic. This nesting site was discovered in would usually land when they spotted suspi- 2006 and checked yearly since then. The cious places and finish their inspections by Rophites nest aggregation occupied about a 3 crawling through the vegetation. The efficien- 3 3 m section of a 40–45u sloping surface on the cy of finding nests seemed rather low, in that sunny edge of a deciduous forest. More than 40 cleptoparasites usually spent a long time nests were observed there at a single time during searching before finding active host nests. the course of our observations. The site was Females of Biastes always immediately enter partly shielded by the forest canopy from rain, a newly discovered nest and probably check its particularly by one old linden tree (Tilia cordata contents. Of 21 visits, most took only a very 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 3 short time (5–47 sec, on average 29 sec), probably indicating that the cell conditions were inadequate for successful egg laying. Seven attempts were probably successful as they took on average 1 min, 48 sec (the longest took 2 min, 30 sec). Interestingly, in about half these cases, the cleptoparasite waited 3–8 sec at the nest entrance before flying away, probably checking the conditions outside but risking confrontation with the host. If the entrance became shaded during the inspection, the parasite waited at the entrance several more seconds. Parasitic behavior at the aggregation often resulted in conflict. Owners of active nests visit their nests many times a day, in that a female of Rophites quinquespinosus spends approxi- mately 15 min inside her nest and 45 min foraging for every hour of daily activity. This means that the nest is protected at least one quarter of the time. Females of Biastes emarginatus fly away immediately when they encounter host females at the nests. A conflict situation happens when a host female returns while a Biastes female is inside the nest. The host grabs the parasite with her mandibles and throws her from the nest entrance. No egg was found even when cell walls were carefully checked. The eggs could be well hidden or possibly laid on/in the spherical provision mass. We encountered six first instars of Biastes emarginatus in four cells; two first instars were Figs. 1, 2. Microphotographs of Biastes emar- found on the surface of the food sphere in ginatus. 1. Mature oocyte, lateral view, showing each of two cells and a single first instar was transparent, glassy chorion. 2. First instar appar- found in each of the other two cells. In one ently attacking another first instar. case of dual occupancy one larva appeared to be attacking the other (fig. 2). This discovery obtain mature oocytes and data concerning demonstrates that in two cases two eggs had the number of ovarioles and mature oocytes been deposited in the chamber, but whether by (summarized in table 1). The number of a single female or separate females remains ovarioles is expressed by a notation that unknown. It almost certainly indicates that on provides the number of ovarioles in each of hatching, this species, like most cleptopara- a female’s two ovaries. For example, the sites, immediately rids the host cell of all but ovarian formula 4:4 refers to four ovarioles one individual, as is necessary if there is stored in each of the female’s two ovaries; this food adequate for only one individual. number is the plesiomorphic number for the Apidae (Michener, 2007). One female of B. OVARIAN STATISTICS AND emarginatus possessed an ovarian formula of MATURE OOCYTE 7:6 (or 7) and the other female was 8:8. Although these counts are uncertain because We dissected and later examined the ovaries of difficulty interpreting the maze of ovarioles of two adult females of Biastes emarginatus to on such small specimens, they confirm that 4 AMERICAN MUSEUM NOVITATES NO. 3667

TABLE 1 Egg Indices, Number of Mature Oocytes, and Number Ovarioles of Biastes emarginatus Compared with Other Biastini Figures in first three columns are averages; data for other Biastini from Rozen (2003: table 1).

Total mature oocytes Per Mature oocytes Taxon Egg index specimen per ovariole Ovariole formula No. of specimens

Biastes emarginatus 0.30 14.5 1.00 7:6–7 2 8:8 Biastes brevicornis 0.18 32 1.60 ,10:,10 1 Neopasites cressoni 0.31 14.5 1.16 6:6 2 7:6 3 5:6 1 Rhopalolemma rotundiceps 0.38 20.7 0.58a 17:14+a 3 aBased on one specimen. like most Nomadinae B. emarginatus has far an artifact of using egg length, a single more ovarioles per ovary than the plesio- dimension, as the criterion for volume, when morphic number (i.e., 4:4) found in many in fact the mature oocyte of B. brevicornis is other Apidae (Rozen, 2003). The numbers for much wider than that of B. emarginatus.A B. emarginatus, however, are lower than those further explanation may be forthcoming found for B. brevicornis (see table 1 for when eggs of the two species are found in situ comparisons with other known Biastini). in host cells. The eggs of Neopasites cressoni As also shown in table 1 the average number Crawford (Torchio et al., 1967) and Rhopa- of mature oocytes in the two females of Biastes lolemma rotundiceps (Rozen et al., 1997) are emarginatus appears to be 14.5, although it is deposited so their dorsal surfaces are parallel difficult to determine with certainty which to and flush with the host cell wall. Rozen and oocytes were completely encased by chorion. O¨ zbek (2003) suggested the same arrangement With this species, as with B. brevicornis (Rozen for B. brevicornis because of the great thick- and O¨ zbek, 2003) (and probably any species ness of the dorsal chorion of that species. that has a thick chorion), there is a gradation in However, the thick anterior chorion of the the development of the thickness of the chorion mature oocyte of B. emarginatus described and especially of the anterior transverse lamel- below does not seems to fit that scenario. If late tubercle. Although an oocyte is considered the thick chorion functions to protect the egg mature when it is surrounded by chorion, full of the cleptoparasite from the mandibles of a deposition of a thick chorion comes later returning host female, chorion thickness only because it requires time after maturity and at the anterior end may suggest that the egg is before oviposition. ‘‘nailed,’’ perhaps obliquely, into the cell wall The egg index of Biastes emarginatus, or pollen mass with its anterior end partly calculated by dividing the length of the largest exposed. A cleptoparasitic egg with only one oocyte (0.64 mm) by the distance between the end exposed in a host cell would more likely outer rims of the female’s tegulae (2.05 mm, escape detection by a returning host female, 2.19 mm) (Iwata and Sakagami, 1966), is 0.29 than a large cleptoparasitic egg with its entire or 0.31 (average 0.30) depends on which dorsal surface exposed: hence the need for B. female is used. The index places the species brevicornis to have extremely small eggs, so as well within the dwarf category (ibid.: table 2) little chorion as possible is exposed to possible with most of the other Nomadinae (Rozen, host detection. It will be interesting to learn 2003: table 1). more about this matter. The egg index of Biastes emarginatus is The following is formatted in accordance substantially higher than 0.18, the index of B. with the descriptions of the egg/mature oo- brevicornis (table 1). The meaning of this cytes of other cleptoparasitic bees in Rozen difference is not clear but might, in part, be and O¨ zbek (2003). 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 5

Figs. 3–7. SEM micrographs of mature oocytes of Biastes emarginatus. 3. Entire oocyte, dorsal view, anterior end to the right. 4. Same, approximate ventral view. 5. Close-up of anterior end, near lateral view. 6. Close-up of micropyle and lamellate tubercle from fig. 5. 7. Anterior end of another oocyte, showing variation in shape of lamellate tubercle, anterodorsal view.

MATURE OOCYTE OF BIASTES EMARGINATUS late tubercle arising from the semitruncate anterior end of the oocyte of B. emarginatus Figures 1, 3–7 (figs. 5, 6) contrasts with the somewhat smaller, more dorsally projecting median DIAGNOSIS: The known eggs/mature oo- lamellate tubercle on the rounded front end cytes of the Biastini show considerable chori- of the mature oocytes of B. brevicornis (Rozen onic variation when one compares Rhopa- and O¨ zbek, 2003: figs. 17, 18). lolemma rotundiceps (Rozen et al., 1997: figs DESCRIPTION: Length measured from pos- 15, 19, 20), Neopasites cressoni (ibid.: figs. 18, terior end to apex of lamellate tubercle/ 26), Biastes emarginatus (figs. 1, 3, 4), and B. micropylar process 0.64 mm; maximum width brevicornis (Rozen and O¨ zbek, 2003: figs. 17, lateral view, measured at right angle to long 18). Despite these differences, as a group, they axis 0.18 mm; egg index 0.30. Shape (based on all uniquely possess a transverse median tuber- fully developed mature oocyte) elongate (ap- cle (described as lamellate in Biastes), which proximately 3.5 3 as long as maximum distinguishes them from all other cleptoparasi- diameter), gently curved in lateral view tic bee eggs/mature oocytes studied to date (fig. 1), with presumed dorsal surface in- (Rozen and O¨ zbek, 2003; Rozen, 2003). curved; widest part in anterior half, rear part The much more elongate shape of the gradually, evenly tapering posteriorly until mature oocyte of Biastes emarginatus imme- rounded posterior end; anterior end obliquely diately distinguishes it from the stouter oocyte subtruncate, flattened, bearing micropylar of B. brevicornis, as do the differences in process on lower edge and with large, thin thickened chorion in the two species (figs. 1, 3, but broad, lamellate tubercle extending from 4; Rozen and O¨ zbek, 2003: fig. 17). The approximate center of truncation (as if to broader, anteriorly projecting median lamel- shelter micropylar process) (figs. 5, 6); anteri- 6 AMERICAN MUSEUM NOVITATES NO. 3667 or edge of lamellate tubercles gently curved ventrally more than that of B. emarginatus, (fig. 7) to somewhat notched (fig. 3) in dorsal/ this matter will need to be checked again when ventral views; periphery of flattened anterior more material becomes available. Under end without flange, such as found in many limited SEM examination no feature could Ammobatini (Rozen and O¨ zbek, 2003); mi- be found whereby the two taxa could be cropylar process knoblike, elongate, forward separated, thus leaving the impression of close projecting, with numerous holes (fig. 6). agreement. Under stereoscope, chorion clear, shiny, With the exception of its greatly reduced glassy, and faintly tinted where thick (fig. 1); maxillary palpus, the first instar of Biastes chorion thickest only at front including emarginatus fits the description of the flattened anterior surface and chorion just Nomadinae based on first instars in Rozen posterior to this surface; elsewhere chorion (1991). evident but evenly thin, without increased DESCRIPTION: Length of newly eclosed thickness of entire dorsal surface, thus unlike larva 0.53 mm; other first stage specimens in B. brevicornis (Rozen and O¨ zbek, 2003: fig. larger. 17); under SEM examination smooth except HEAD: Maximum transverse width of head with faint polygonal pattern. capsule 0.19 mm; maximum transverse fora- MATERIAL STUDIED: Oocytes from two men width 0.11 mm. Shape slightly progna- females, Czech Republic: Praha-Misˇkovice, thous because of ventral surface extension of 3-VIII-2008 (K. Rezkova and J. Straka lgt.). posteroventral constriction of parietals and REMARKS: Although we had hoped to presence of partial or complete postoccipital compare the mature oocytes of Biastes emar- bridge (figs. 12, 14); head capsule not dorso- ginatus and its host, Rophites quinquespinosus, ventrally flattened; parietals swollen laterally the one preserved specimen of the host and dorsolaterally immediately in front of contained a single large oocyte, which appar- posterior constriction at rear of head capsule; ently was still not mature. vertex appearing bilobed because of median depression; in lateral view (figs. 8, 18) head FIRST INSTAR OF BIASTES shape similar to that of Townsendiella pulchra EMARGINATUS Crawford (Rozen, 1991: fig. 9). Integument of head capsule strongly sclerotized, moderately Figures 8–19 pigmented, as characteristic of hospicidal The format used here follows that in the nomadine first instars; sclerotization ending descriptions of first instars of cleptoparasitic at posterior margin of head capsule; capsule Apidae (Rozen, 1991). The only other avail- without ring of sharp-pointed spinulae across able first instar is Neopasites cressoni, whose vertex as in Melectini (Rozen, 1991) but with description is appended. These are the first linear row of simple setiform sensilla arising SEM studies of any first-stage larva of the from shallow pits, extending across top of Nomadinae. cranium from mandibular bases (fig. 9). DIAGNOSIS: Although slightly larger and Tentorium weak, not certainly complete; with parietals somewhat more swollen com- anterior tentorial pit not evident on SEM pared with the first instar of Neopasites micrographs, but present as small spot above cressoni (description appended below), these base of mandible somewhat mesad of imagi- two larvae are similar when examined by light nary line through antenna paralleling median microscope. The head shapes in lateral view line; posterior tentorial pits small put present appear to differ in that the front of the head of (fig. 12); hypostomal groove/ridge present first-instar Biastes emarginatus in outline is (figs. 8, 12, 14), darkly pigmented; sclerotiza- straight as it rises to the curvature at the tion extending mesad (below in lateral view) of crown (fig. 18) whereas it is gently curved in each hypostomal groove, presumably repre- N. cressoni (fig. 20). The paired labral tuber- senting fused cardo and stipes, described cles of B. emarginatus are more slender than below; pleurostomal and epistomal ridges those of N. cressoni. Although the labiomax- not evident because of general thickness of illary region of N. cressoni may project integumental sclerotization; ecdysial line not 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 7

Figs. 8–15. SEM micrographs of head of first instar Biastes emarginatus. 8. Entire head lateral view. 9. Close-up of top of head showing position of antenna and linear row of sensilla across top. 10. Close-up of antenna with 4 sensilla. 11. Close-up of labrum, approximate lateral view. 12. Ventral view of head from behind showing mandibles and labiomaxillary region. 13. Close-up of labrum, approximate ventral view. 14. Close-up of labiomaxillary region, identified by rectangle in fig. 8, dashed line demarking boundary of sclerotized (above) and membranous (below) areas. 15. Close-up of membranous area of figure 14 identifying palpi and salivary opening. PTP 5 posterior tentorial pit. 8 AMERICAN MUSEUM NOVITATES NO. 3667

Figs. 16, 17. SEM micrographs of first instar of Biastes emarginatus. 16. Integument of first abdominal segment showing transverse, multidentate spicules. 17. Close-up of area identified by rectangle in fig. 16. evident; posterior margin of head capsule at BODY: Form elongate, tapering posteriorly approximate right angle to hypostomal groove (newly eclosed) to straight sided (after some in lateral view (figs. 8, 18). Antenna (figs. 8– feeding), without paired lateral tubercles on 10) small, scarcely protuberant, inconspicu- segments; abdominal segments 8–10 becoming ous, with 3 or 4 sensilla. Labrum membranous progressively smaller, giving pointed appear- except for pair of elongate, sclerotized tuber- ance to posterior part of body; segment 10 cles apically beset with fine, bristlelike sensilla small, bearing apically paired lobes, possibly (figs. 11–13); epipharyngeal surface (figs. 11, eversible, presumably functional as pygopod. 13) with small median protuberance beneath Integument with a few minute setae anteriorly base of tubercles, laterad of which a pair of but extensively covered, especially ventrally minute but elongate double sensilla on each and laterally, with minute transverse, pos- side. Mandible (figs. 8, 12) elongate, many teriorly sloping projections (thus cleatlike), times longer than basal diameter, apically each consisting of rows of 1–5 or 6 sharp slender, tapering, curved, bearing a few points visible only with SEM (figs. 16, 17). sharply pointed sensilla at midlength but more Information concerning spiracles not avail- at base. Labiomaxillary region scarcely pro- able. Position of anus not identified. tuberant in lateral view (figs. 8, 12, 18) with MATERIAL STUDIED: Three first instars, cardo and lateral part of stipes fused as single Czech Republic: Praha-Misˇkovice, 3-VIII- sclerite attached to parietal (figs. 8, 12, 14); 2008 (K. Rezkova and J. Straka lgt.). posterior part of this sclerite extending mesad REMARKS: The differences in body size to form ventral postoccipital bridge or partial among three specimens demonstrate the flex- bridge to head (figs. 12, 14); rest of labiomax- ibility of the body wall to expand as well as a illary region U-shaped, membranous, bearing substantial intake of food during the first maxillary and labial palpi as well as median stadium. salivary opening (figs. 14, 15); maxillary pal- The small, transverse, dentate, integumental pus (fig. 15) apparently a small tubercle projections (figs. 16, 17) presumably are mod- with single long seta; two smaller setae ified spicules, which probably assist the larva (fig. 15) posterior to palpus presumably on in crawling as it searches for the host’s maxilla, rather than on palpus; labial palpus a offspring or larval competitors. Since similar single seta on small tubercle posterior to and projections occur on first instars of Neopasites laterad of salivary opening. Hypopharynx cressoni, we wonder how extensively they will apparently sclerotized with simple, curved be found among other Nomadinae. anterior edge forming ventral edge of mouth There is a striking resemblance among (figs. 13, 19). known first instars of Neolarra probably 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 9

Figs. 18, 19. Microphotographs of cleared head of Biastes emarginatus, lateral (18) and ventral (19) views, respectively. Fig. 20. Microphotographs of cleared head of Neopasites cressoni, lateral view, showing greater curvature to frontal profile. Fig. 21. Microphotograph of side of cleared head of mature larvae of Biastes emarginatus, showing texture of integument associate with rear part of head. Fig. 22. Microphotograph of spiracle of mature larva of Biastes emarginatus, side view. PTP 5 posterior tentorial pit. vigilans (Cockerell)3, Townsendiella pulchra various cladograms in Rozen (1996a) and fig. (Rozen, 1991), Neopasites cressoni (descrip- 45 in Rozen et al. (1997), an examination of a tion appended), and Biastes emarginatus in the broad spectrum of nomadine taxa suggests shape of the head in lateral view. It is created that a more thorough and detailed examina- by the extreme elevation of the rear part of the tion of their anatomy needs to be pursued head capsule resulting in a more-or-less before conclusions should be drawn. straight lateral profile from the base of the clypeus to the highest point of the head capsule followed by an abrupt decline to the POSTDEFECATING LARVA postoccipital ridge. Although it is tempting to Figures 21, 27–30 speculate that these shared similarities are evidence of close relationships expressed in DIAGNOSIS: The mature larvae of the Biastini share a number of features with 3 Specimen in the collection of the American Museum of Neolarrini and Townsendiellini. Characters Natural History. held in common by the three tribes include 10 AMERICAN MUSEUM NOVITATES NO. 3667

Figs. 23–26. SEM micrographs of first instar of Neopasites cressoni. 23. Head, near frontal view. 24. Close-up of part of left side of head in fig. 23. 25. Head, ventrolateral view. 26. Head, of another specimen, approximate ventrolateral view. ATP 5 anterior tentorial pit. the strongly produced frontal area on the parietals higher than the vertex at midline head, recessed labroclypeal area in lateral (Rozen and McGinley, 1991: fig. 8), unlike the view, apex of mandible thin and attenuate, simple, evenly curved vertex of the Biastini maxillary palpus not projecting and nearly (fig. 29). The mature larva of Biastes emargi- absent (visible as sensilla-bearing pale area on natus will key successfully to Rhopalolemma in cleared head capsule), and protruding venter Rozen (2001). Whereas the paired dorsal body of abdominal segment 9 (abdominal segment tubercles of Neopasites cressoni are scarcely 10 attached dorsally). In Neolarra pruinosa the evident (Rozen et al., 1997: fig. 32)4, those of anus is apical on a prolonged abdominal B. emarginatus and R. rotundiceps are low but segment 10 (Rozen, 1966: fig. 79). The very obvious on most segments (fig. 27). The short abdominal segment 10 (fig. 27) is clypeus is strongly recessed in R. rotundiceps, another distinctive feature of the Biastini so that labrum is produced slightly beyond the shared with Townsendiella (Rozen and clypeus in lateral view (ibid., fig. 35) unlike in McGinley, 1991: fig. 7), and, except for B. emarginatus. Neopasites cressoni (Rozen, 1966: fig. 72), the anus is positioned on the sloping dorsal

Town- 4 surface of segment 10 (fig. 27). In The tubercles seem more pronounced in the illustration sendiella pulchra the head capsule is extremely of Rozen (1966: fig. 72), which questions the reliability of broad in frontal view with the top of the this character. 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 11

Figs. 27–30. Diagrams of postdefecating larva of Biastes emarginatus. 27. Entire larva, lateral view. 28. Right mandible, outer view. 29, 30. Head, frontal and lateral views respectively. ATP 5 anterior tentorial pit; PTP 5 posterior tentorial pit. 12 AMERICAN MUSEUM NOVITATES NO. 3667

DESCRIPTION: Length approximately 8.0 mm. tentorial pits and between pits and anterior Head (figs. 29, 30): Pigmentation, even of man- mandibular articulations. Parietal band a dibles, weak; sensilla nonsetiform; much of faint integumental scar. Antennal prominence integument minutely wrinkled; hypopharyngeal indistinguishable from forward projecting area, maxillae, and lateral parts of labium at base frontoclypeal region; antenna positioned nor- finely, extensively spiculate. mally on front of head capsule; antennal Head size moderately small compared with papilla, small but distinct, projecting, bearing body; head capsule wider than long and 3–4 sensilla. Labrum short, small, recessed dorsally rounded in frontal view; as seen in compared with projecting frontal region, lateral view (fig. 30), frontal area projecting without sclerite, with pair of very small, well strongly forward, overhanging labroclypeal separated tubercles on disc; epipharynx a area. Tentorium nearly complete, extremely short (because of short labrum), simple, thin (dorsal arms probably missing); anterior curved surface. tentorial pit extremely small, easily overlooked Mandible (figs. 28, 29) extremely short so that because of absence of epistomal ridge, situated when closed apex far removed from apex of close to but above and slightly mesad of apposing mandible, each ending beneath respec- anterior mandibular articulation, as in fig. 29; tive labral tubercle; mandible straight, apically anterior tentorial arms extremely thin, taper- tapering to fine point; dorsal and ventral apical ing; posterior tentorial pit small, situated in edges with distinct, sharply pointed, apically hypostomal groove short distance (figs. 22, directed fine teeth; in external profile, upper 30) in front of cervical line; posterior arm apical mandibular edge measured from basal directed mesad, tapering, and apparently articulation to apex much shorter than lower ending before reaching opposite one. edged, as in Neopasites cressoni (Rozen, 1966: Postoccipital ridge not evident, so that poste- fig. 74); apex not curved toward mouth; cusp rior margin of head capsule uncertain (as in and apical concavity not differentiated. Maxillae Rhopalolemma rotundiceps; see description in and labium strongly fused into bulbous labio- Rozen et al., 1997) but possibly cervical line maxillary region that in lateral view (fig. 30) is identified in figs. 21, 29, and 30, although this broadly attached to body. Maxillary apex line passing well behind posterior tentorial pit slightly surpassed by labial/hypopharyngeal and fading out toward bottom of head in 5 apex in lateral view (fig. 30); galea and maxillary lateral view; parietal with furrow anterior to sclerites including articulating arm of stipes cervical line (also in R. rotundiceps) running absent; lateral integument of side of maxilla roughly parallel to line and seemingly directed densely spiculate; maxillary palpus not project- toward posterior tentorial pit; integumental ing, represented by wrinkled integument bearing texture (fig. 21) between furrow and cervical sensilla on cleared specimen. Labium not line finely, transversely wrinkled, nonspicu- divided into pre- and postmentum; premental late, integument in front of area nonspiculate, sclerite absent; labial palpus not projecting, with fewer wrinkles, none of which are below and laterad of salivary opening, similar transverse, area behind cervical line non- to but smaller than maxillary palpus. Salivary wrinkled and densely spiculate in most areas; opening simple, circular, without lips, situated area behind furrow flaring outward along below and posterior to labial/hypopharyngeal sides of parietals, so that head in frontal view apex in lateral view (fig. 30); salivary duct with two outlines laterally (fig. 29). Median pigmented, swollen shortly before opening. longitudinal thickening of head capsule ab- Hypopharyngeal groove faintly distinct (becom- sent; hypostomal groove/ridge evident, short ing unidentifiable on strongly sclerotized indi- as measured from ventral mandibular articu- viduals); hypopharyngeal surface spiculate area lation to posterior tentorial pit, fading out at dorsal to and behind nonspiculate labial apex. pit, as seen in lateral view (figs. 21, 29); pleurostomal ridge weak, not clearly defined; Body (fig. 27): Without setae but with epistomal ridge absent both between anterior scattered nonsetiform sensilla especially on apices of paired dorsal tubercles; integument 5 This furrow is more linear in Rhopalolemma rotundiceps very finely spiculate in some area but spicules (Rozen et al., 1997: fig. 35). often difficult to identify because of pattern of 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 13 fine, transverse wrinkles that tend to be cladistic analyses (Alexander, 1990; Rozen, parallel except on apices of dorsolateral 1996a; Rozen et al., 1997) with high bootstrap tubercles, where wrinkles are multidirectional; support for the Neolarrini-Biastini relation- integument without spines or sclerotized ship (Townsendiellini not included) (Straka tubercles. Body form moderate in robustness, and Bogusch, 1997b). Five characters listed in not quite as slender as that of Neopasites the diagnosis of mature larvae can be expand- cressoni or Rhopalolemma rotundiceps (Rozen ed by a specific combination of adult charac- et al., 1997: figs. 32, 33); intersegmental lines ters shared by bees of these three tribes: weakly incised between most body segments; propodeal profile with a nearly horizontal dorsolateral intrasegmental lines not evident; basal zone, a gonocoxite with an internal each thoracic segment with weakly evident, septum, and the presence of a ventral para- paired dorsolateral tubercles; abdominal seg- pennial lobe with strong setae of the gonocox- ments 1–7 with paired dorsolateral tubercles ite. The only bee with a similar adult character somewhat more evident but absent on seg- combination is Hexepeolus rhodogyne (Linsley ments 8–10; all dorsolateral tubercles moder- and Michener); however, its mature larvae are ately low, conical (as opposed to transverse); largely different (see Rozen, 1996b). venter of abdominal segment 9 in lateral view Biastini, Townsendiella,andNeolarra prob- (fig. 27) appearing somewhat produced be- ably form a well recognizable clade like the cause of dorsal attachment of segment 10; morphologically diverse clades within the segment 10, short with length much less than tribes Ammobatini, Ammobatoidini, Bra- one-half height in lateral view (fig. 27), at- chynomadini, and Epeolini. However, a com- tached dorsally to 9 (fig. 27); anus a transverse prehensive phylogenetic analysis based on bee slit on sloping dorsal surface of 10 (fig. 27); morphology and possibly DNA sequences is perianal area with small dorsal lip immediate- needed. ly above anus that is to width of anus. The nest-searching behavior we describe Spiracles (fig. 22) subequal and moderate in here for Biastes emarginatus is similar to that size, projecting beyond body wall, with rims; of many small nomadine cleptoparasites that peritreme present, moderately wide; atrium attack nests of ground-nesting solitary bees. globular, pigmented; atrial wall without den- Like many cleptoparasitic bees that deposit ticles or rings; primary spiracular opening their eggs in cells that are still open and thus with collar; subatrium moderately short, in likely revisited by host females, their eggs/ side view tapering from body surface inward, mature oocytes are small and possess a thick, with about 8 chambers. Male with median presumably protective chorion against attack integumental scar toward posterior margin of by host females. The configuration of the abdominal segment 9; female sex characters chorion suggests that the eggs may be unknown. embedded in the pollen sphere and/or the cell MATERIAL STUDIED: Six postdefecating lar- wall, to make them less obvious to host vae, Czech Republic: Praha-Misˇkovice, 1-IX- females. The first instars are small as probably 2007, 18-VIII-2008 (K. Rezkova and J. Straka dictated by the small egg size and, like those of lgt.); host: Rophites quinquespinosus. other Nomadinae, possess adaptations for REMARKS: The description of an immature seeking out and battling eggs/larvae of the larva of this species from Switzerland (Rozen, host or of competing cleptoparasites. These 1993), though far less complete, is in agree- adaptations consist of a heavily sclerotized ment with the above description. head capsule, large, curved, sharply pointed mandibles, elongate labral tubercles, and the DISCUSSION AND CONCLUSIONS ability to crawl, presumably with the aid of a terminal pygopod and transverse, cleatlike Similarity in morphology both of first spicules (reported here for the first time) on instars and of mature larvae among the tribes the body surface. Biastini, Neolarrini, and Townsendiellini may As with many cleptoparasitic bees with indicate a close relationship of these bees. This specialized hospicidal early instars, the larval similarity was recognized several times in instars of Biastes emarginatus exhibit a sub- 14 AMERICAN MUSEUM NOVITATES NO. 3667 stantial anatomical modification between the The project was partly supported by the hospicidal stage and subsequent instars, which Research Program of the Ministry of Education presumably are devoted to consuming provi- of the Czech Republic No. 0021620828 (for sions. One would assume that the anatomy of Jakub Straka). the last larval instar would reveal obvious, perhaps plesiomorphic features for ingesting REFERENCES provisions, such as scoop-shaped mandibles powered by mandibular muscles attached to Alexander, B. 1990. A cladistic analysis of the the parietals, and parietal architecture that nomadine bees (Hymenoptera: Apoidea). Sys- supports associated muscular contraction for tematic Entomology 15: 121–152. biting into the provisions. As an example we Baker, J.R. 1971. Development and sexual dimor- phism of larvae of the bee genus Coelioxys. clearly see this is the situation with Coelioxys Journal of the Kansas Entomological Society (Megachilidae) (e.g., Baker, 1971). However, 44: 225–235. this does not seem to be the case for Biastes Iwata, K., and S.E. Sakagami. 1966. Gigantism and emarginatus, Neopasites cressoni, and likely dwarfism in bee eggs in relation to the mode of for some (if not many) other Nomadinae. life, with notes on the number of ovarioles. With B. emarginatus, the mandibles of the last Japanese Journal of Ecology 16: 4–16. instar are so short that in repose their apices McGinley, R.J. 1981. Systematics of the Colletidae are far separated, they are not scoop shaped, based on mature larvae with phenetic analysis and the head capsule is thinly sclerotized and of apoid larvae. University of California Publications in Entomology 91: i–xvi 1–307. so week that not only is it not constricted + Michener, C.D. 2007. The bees of the world. 2nd behind (suggesting weak musculature), but the ed. Baltimore, MD: Johns Hopkins University posterior margin of the capsule cannot be Press, 953 pp. certainly identified (is it the cervical line or the Rozen, J.G., Jr. 1966. The larvae of the Antho- anterior, faint furrow that is directed toward phoridae (Hymenoptera, Apoidea). Part 2. The the posterior tentorial pits? if the former, how Nomadinae. American Museum Novitates 2244: then do we account for the anterior furrow?). 1–38. The postoccipital ridge is absent. The intrigu- Rozen, J.G., Jr. 1991. Evolution of cleptoparasitism ing questions are: how does this animal feed in anthophorid bees as revealed by their mode and how do we explain its peculiar morphol- of parasitism and first instars (Hymenoptera: Apoidea). American Museum Novitates 3029: ogy? The answers will probably come from 1–36. fieldwork: observing them as they feed, not Rozen, J.G., Jr. 1993. Nesting biologies and im- only the first and last instars, but the mature stages of the rophitine bees (Halic- intermediate ones as well. Because mandibles tidae) with notes on the cleptoparasite Biastes of the last instar seem ineffectual for chewing (Anthophoridae) (Hymenoptera: Apoidea). into food and forcing the food into the American Museum Novitates 3066: 1–28. esophagus, might an internal study of this Rozen, J.G., Jr. 1996a. Phylogenetic analysis of structure reveal some sort of cibarial or the cleptoparasitic bees belonging to the esophageal pump, thereby explaining the Nomadinae based on mature larvae (Apoidea: Apidae). American Museum Novitates 3180: rotund projection of the front of the head 1–39. capsule? Rozen, J.G., Jr. 1996b. First and last larval instars of the cleptoparasitic bee Hexepeolus (Hymenop- ACKNOWLEDGMENTS tera: Apidae: Nomadinae). Memoirs of the Entomological Society of Washington 17: Illustrations were arranged by Steve Thurston, 188–193. Senior Scientific Assistant, American Museum Rozen, J.G., Jr. 1997. Pupal description of Neopasites of Natural History (A.M.N.H.), who also cressoni (Apidae: Nomadinae: Biastini). Journal of the Kansas Entomological Society 70: 76–78. photographed figure 2. Christine LeBeau, Rozen, J.G., Jr. 2001. Taxonomic key to mature Scientific Assistant, A.M.N.H., took all SEM larvae of cleptoparasitic bees (Apoidea). microphotographs in the A.M.N.H. Microscopy American Museum Novitates 3309: 1–27. and Imaging Facility (Rebecca Rudolph, Rozen, J.G., Jr. 2003. Eggs, ovariole numbers, and Laboratory Manager). modes of parasitism of cleptoparasitic bees, with 2009 ROZEN ET AL.: BEHAVIOR OF BIASTES EMARGINATUS 15

emphasis on Neotropical species (Hymenop- TownsendiellaStraka, J., and P. Bogusch. 2007a. tera:). American Museum Novitates 3413: Description of immature stages of cleptopar- 1–36. asitic bees Epeoloides coecutiens and Leiopodus Rozen, J.G., Jr., and R.J. McGinley. 1991. Biology trochantericus (Hymenoptera: Apidae: Osirini, and larvae of the cleptoparasitic bee Townsendiella Protepeolini) with remarks to their unusual pulchra and nesting biology of its host Hesper- biology. Entomologica Fennica 18: 242–254. apis larreae (Hymenoptera: Apoidea). American TownsendiellaStraka, J., and P. Bogusch. 2007b. Museum Novitates 3005: 1–11. Phylogeny of the bees of the family Apidae Rozen, J.G., Jr., and H. O¨ zbek. 2003. Oocytes, based on larval characters with focus on eggs, and ovarioles of some long-tongued bees the origin of cleptoparasitism (Hymenoptera: (Hymenoptera: Apoidea). Appendix: Param- Apiformes). Systematic Entomology 32: 700– mobatodes rozeni, a new bee species from Israel, 711. by M. Schwarz. American Museum Novitates TownsendiellaTorchio, P.F., J.G. RozenJr., G.E. 3393: 1–35. Bohart, and M.S. Favreau. 1967. Biology of TownsendiellaRozen, J.G., Jr., A. Roig-Alsina, and Dufourea and of its cleptoparasite, Neopasites B.A. Alexander. 1997. The cleptoparasitic bee (Hymenoptera: Apoidea). Journal of the New genus Rhopalolemma, with reference to other York Entomological Society 75: 132–146. Nomadinae (Apidae) and biology of its host Westrich, P. 1989. Die Wildbienen Baden- Protodufourea (Halictidae: Rophitinae). Ameri- Wurttembergs. Allgemeiner Teil: 1–431, Speziel- can Museum Novitates 3194: 1–28. ler Teil: 432–972. Stuttgart: Eugene Ulmer.

APPENDIX groove present, darkly pigmented; sclerotization mesad (below) of each hypostomal groove present as in B. emarginatus; other features of parietal FIRST INSTAR OF NEOPASITES CRESSONI about as described for B. emarginatus. Antenna Figures 20, 23–26 (fig. 24) as described for B. emarginatus. Labrum as The first instar of Neopasites cressoni is described described for B. emarginatus except paired tubercles here to allow a comparison with the first instar of stouter at base and information about epipharyn- Biastes emarginatus. The description is based geal surface unknown. Mandible as described for B. mostly on a cleared specimen, but the SEM emarginatus. Labiomaxillary region probably much micrographs are of two of seven specimens found like that of B. emarginatus because of fusion of dead in a single cell, presumably having been killed cardo with lateral parts of stipes while rest of region earlier by other cleptoparasites. While heavily remaining membranous except perhaps membra- sclerotized areas were relatively unaffected, mem- nous part more ventrally protuberant although branous areas, including the labrum and labiomax- SEM micrographs (figs. 23, 25, 26) show this area illary regions shrank and became distorted through badly desiccated due to postmortem deterioration; postmortem processes. Many setae were also posterior part of fused cardo/stipes sclerite forming broken, for reasons not understood. ventral postoccipital bridge (fig. 23), except bridge DIAGNOSIS: See Diagnosis of first instar of perhaps not fused medially; identification of Biastes emarginatus above. maxillary and labial palpi as well as median salivary DESCRIPTION: Length of newly eclosed specimen opening uncertain (figs. 23, 25, 26). Hypopharynx 0.44 mm. apparently sclerotized as in B. emarginatus. HEAD: Maximum transverse width of head BODY: Form elongate, linear, as described for capsule 0.18 mm; maximum transverse foramen Biastes emarginatus. Integument with a few minute width 0.13 mm. Shape about as described for setae anteriorly and with minute, transverse, poste- Biastes emarginatus except foramen magnum not riorly sloping projections consisting of rows of 1–5+ nearly as constricted and parietals not swollen as sharp points visible only with SEM, as in Biastes greatly dorsolaterally, so the median depression of emarginatus (fig. 17). Spiracular peritreme flush with vertex less exaggerated, only faintly lower than body wall (fig. 25). Position of anus unknown. lateral parts of vertex in frontal view; integument of MATERIAL STUDIED: Seven first instars, USA: head capsule about as described for Biastes Arizona: Cochise Co., 3 mi SW of Rodeo, Hidalgo emarginatus; capsule clearly with simple setae, not Co., New Mexico, V-1-1965 (J.G. Rozen), presum- spinulae but arrangement uncertain. Tentorium ably all collected dead; one first instar, same data weak, not certainly complete; anterior (fig. 24) except IV-27-1966 (J.G. Rozen, M. Favreau), and posterior tentorial pits present; hypostomal collected alive.

gomplete lists of —ll issues of the xovit—tes —nd the fulletin —re —v—il—˜le —t ‡orld ‡ide

‡e˜ site httpXGGli˜r—ryF—mnhForgGpu˜sF snquire —˜out ordering printed ™opies vi— eEm—il from

s™ipu˜sd—mnhForg or vi— st—nd—rd m—il fromX emeri™—n wuseum of x—tur—l ristoryD

vi˜r—ryЃ™ientifi™ €u˜li™—tionsD gentr—l €—rk ‡est —t UWth ƒtFD xew ‰orkD x‰ IHHPRF „ivX

@PIPA UTWESSRSF peˆX @PIPA UTWESHHWF

„his p—per meets the requirements of exƒsGxsƒy QWFRVEIWWP @€erm—nen™e of €—perAF