Trichocolletes orientalis BATLEY AND HOUSTON

Rozen, Jerome G. & Houston, Terry F., 2022, Descriptions of the Mature Larvae of Three Australian Ground-Nesting Bees (Hymenoptera: Colletidae: Diphaglossinae and Neopasiphaeinae), American Museum Novitates 2022 (3989), pp. 1-16 : 5-8

Trichocolletes orientalis BATLEY AND HOUSTON

Figures 9–13

DIAGNOSIS: Larva similar to known Neopasiphaeinae in not spinning a cocoon; labium recessed in lateral view; salivary opening small, at most only slightly protruding and oval. Unique in labrum bearing pair of extremely large, down-curved apical tubercles (figs 12, 13). Unlike Leioproctus wanni in frons being convex, not broadly depressed.

All four available larvae of this species were predefecating, characterized by their seemingly bloated body (fig. 9) and thinner and more transparent cuticle than in most postdefecating larvae of other bees. These specimens were collected by T.F.H., who also reported on their biology ( Houston, 2020b).

HEAD: Very small relative to bloated predefecating body (fig. 9). Integument of cleared head capsule translucent, not strongly wrinkled as in specimen of L. wanni described above, but difference possibly due to developmental stage. On cleared, stained head capsule, posterior thickening of head capsule narrow but distinct; pleurostomal and epistomal ridges faintly evident; median coronal ridge not evident; parietal bands only moderately impressed (fig. 12); in lateral view (fig. 11), profile of integument mesad of parietal band normally curved and antennal mound only moderately produced, hence profile of clypeus and frons above, not eclipsed by moderate antennal mound (fig. 11). Epistomal ridge arching upward from anterior tentorial pits to near level of antenna in frontal view (figs. 10, 12). Because of these features, surface of face in frontal view of mature larva (fig. 12) not dominated by large depression created by mounds mesad of parietal bands, large antennal mounds, and short clypeus, all as pictured for L. wanni (fig. 4). Labrum bearing pair of extremely large, down-curved apical tubercles (figs 10–13). Mandible elongate, ending in darkly pigmented, sclerotized, sharply pointed apex, with cuspal area weakly produced, and dorsal apical edge with linear row of 7 or 8 strongly developed, sharply pointed teeth; ventral apical edge apparently without teeth. Maxillae moderately large, with tapering palpi somewhat shorter than those of L. wanni . Labium recessed, short in lateral view (fig. 11) with scarcely projecting, unpigmented palpi. Salivary opening faintly projecting, probably oval when open, but capable of closing when dorsal edge curves downward (fig. 13).

BODY: In lateral view (fig. 9) body segments of mature larva enlarged and intersegmental constrictions much reduced because of predefecating condition; terminal abdominal segment as illustrated and most body segments at most weakly subdivided dorsally into anterior and posterior annulets. Posterior annulets without dorsolateral projections or ridges. Atrial surfaces densely spiculate. Because of predefecating condition, dark content of alimentary tract of preserved larva vaguely evident at some intersegmental constrictions.

MATERIAL EXAMINED: Four predefecating, mature larvae: Trichocolletes orientalis , ex brood cell 3/xii/2020, Yanchep National Park , Western Australia, 31.5431° S, 115.6895° E, T. F. Houston 1598-1 .

DISCUSSION: Houston’s (2020b) treatment of the nesting biology and larva of T. orientalis provides a wealth of information about that species. It also offers some biological insight regarding Trichocolletes venustus (Smith) , T. dowerinensis Rayment , and T. species indeterminate.

The salivary opening and small labial tubercles of larvae of both T. orientalis and L. wanni are similar and contrast strongly with the elongate spoutlike salivary opening with associated elongate labial palpi of P. crassipes , below.

Figures

FIGURES 9–11. Diagrams of predefecating larva of Trichocolletes orientalis Batley and Houston. 9. Entire larva, lateral view. Scale bar = 2 cm. 10, 11. Head, frontal and lateral views.

FIGURES 12, 13. SEM micrographs of predefecating larva of Trichocolletes orientalis. 12. Front of head. 13. Close-up of mouthparts, noting huge down-curved labral tubercles and uncertain arrangement of spicules on maxilla as well as clear arrangement of labial palpi laterad of only slightly projecting salivary opening.