Systropha planidens, Giraud, 1861

Rozen, Jerome G. & ÖZbek, Hikme T., 2008, Immatures of Rophitine Bees, with Notes on their Nesting Biology (Hymenoptera: Apoidea: Halictidae), American Museum Novitates 3609 (1), pp. 1-36 : 16-19

planidens Giraud

Figures 38–46

DIAGNOSIS: Because of its projecting labiomaxillary regions, this species can easily be distinguished from Conanthalictus . The clear presence of the articulating arm of the stipes separates it from all known Dufourea and Sphecodosoma , and characters presented in the key will enable it to be separated from the other taxa treated here.

HEAD (figs. 39, 42): Integument of head capsule as described for Dufourea holocyanea . Integument unpigmented except for mandibular apices.

Other head features as described for Dufourea holocyanea except for following: median longitudinal thickening of head capsule absent; antennal disc moderate in size, its diameter about 0.8 times distance between its lower margin and center of anterior tentorial pit; antennal papilla projecting less than onehalf basal diameter; labrum with low labral tubercles (rather than merely bilobed as in D. holocyanea ) though not surpassing clypeus in lateral view.

Mandible (figs. 40, 41) as described for Dufourea holocyanea except more sinuate in aboral and adoral views (figs. 40, 44) and tubercle cluster less projecting on outer surface (fig. 41). Labiomaxillary region projecting in lateral view but not as strongly as in Dufourea and Sphecodosoma . Inner surface of lower lip with parallel ridges (figs. 45, 46) similar to those of D. holocyanea ; microstructure of inner surface of upper lip uncertain. Other feature of maxilla and labium as described for D. holocyanea , except for following: articulating arm of stipital sclerite evident. Hypopharynx as described for Dufourea holocyanea .

BODY: Integument as described for predefecating Dufourea holocyanea . Body shape- [?or change ‘‘form’’ 3X in this same clause to ‘‘larva’’?] of postdefecating form unknown; intersegmental lines moderately weakly incised on predefecating form, unknown on postdefecating form; paired prothoracic dorsal tubercles present, more sharply defined but apparently smaller than those of mesothorax, metathorax, and most abdominal segments (fig. 38); all tubercles conical (not transverse); midbody tubercles appearing apically rounded but with apical surfaces thicker and finely wrinkled, so that those of postdefecating larva possibly truncate; abdominal segment 9 strongly produced ventrally; abdominal segment 10 positioned dorsally on 9 as seen in lateral view (fig. 38); on predefecating larva, ventral integument of segments 9 extended, causing segment 10 to be partly tilted and making anus appear somewhat dorsally on 10; ventral integument of segment 9 on postdefecating larva unknown. Spiracles small; those of thorax slightly larger than those of abdomen, those of predefecating larva without sclerites; those of postdefecating larva unknown; other spiracular features as describe for D. holocyanea except subatrium consisting of about 10 chambers. Male with median, transverse, integumental scar ventrally near apex of protrusion of segment 9 of predefecating larva, unknown on postdefecating larva; female sexual characters visible on predefecating larva as small, paired, ventral, pale, subcutaneous imaginal discs arranged sublaterally on abdominal segments 7, 8, and 9, with those of 7 farthest apart and those of 9 closest.

MATERIAL STUDIED: 4 predefecating larva, Turkey: Erzurum: Atatürk University campus, N 39 ° 54 9 09 0 E 41 ° 14 9 06 0, July 4, 2001 (J.G. Rozen); 2 predefecating larvae, same except July 1, 2001 (J.G. Rozen, H. Özbek) .

REMARKS: We studied two nests of this species July 1, 2001, on the campus of Atatürk University (see fig. 63). Main burrows were open, with diameters of 5.0 and 5.5 mm, and descended more or less vertically. Cells were arranged singly and occurred between the depths of 8 and 14 cm. Because the nests were still early in construction, other cells would likely have been added at lower depths. Cells, symmetrical around their long axis, were nearly horizontal, their rears tilted slightly downward. They appeared ovoid (fig. 47), like the cells of other rophitines, in that their length ranged from 9.5 to 12.0 mm (N 5 3) and their maximum diameter was 8.0 mm (N 5 2). Cell walls were dull, smooth, without any evidence of a shiny lining, but the fine- grained surface was presumably smoothed by some activity of the female. When a water droplet was applied to the wall, the droplet was absorbed almost immediately. A number of cell walls had irregular gouges (fig. 47), very possibly created by the Systropha female removing cleptoparasite eggs with her mandibles. Biastes brevicornis (Panzer) ( Apidae : Nomadinae: Biastini), a confirmed parasite of this and another species of Systropha ( Warnke, 1982) , was collected in the area. One cell closure (fig. 48) was shallowly concave on the inner surface and had 3–4 coils to the radius. Laterals, backfilled after cell closure, were 8–10 mm in length (N 5 2). Provisions were spherical, and two were 5.0 mm in diameter. The above information is consistent with that presented by Malyshev (1925a) concerning the nesting biology of this species, the larva of which, as he points out, ‘‘spins a cocoon and ejects excrements’’ and ‘‘hibernates curled up and lying freely in the cocoon.’’ Grozdanić and Vasić (1968) described nests of this species and reported that one nest was 48 cm deep, far deeper than ours. In most other respects the nest construction was similar to that of our nests including burrow diameter and cell size. However, they reported that inner surface of the cells were shiny (‘‘glänzed’’); we think this is unlikely since all other rophitines about which we have information characteristically have dull inner surfaces, including those of S. planidens preserved in the AMNH from the current study.

Batra and Michener (1966) described a nest and an immature larva of the closely related Systropha (Systropha) punjabensis Batra and Michener.

Mature Larvae of Rophites (Rhophitoides)

Figures

Figs. 38–41. Systropha planidens. 38. Predefecating larva, lateral view. 39. Head, frontal view. 40, 41. Right mandible, inner and ventral views, respectively. Scale refers to fig. 38.

Figs. 42–46. SEM micrographs of predefecating larva of Systropha planidens. 42. Head, frontal view. 43. Left antenna. 44. Close-up of left mandible, outer view, showing outer, apical tubercle cluster and sinuate shape of apex. 45. Apex of labiomaxillary region. 46. Close-up of salivary opening identified by rectangle in fig. 45.