Unidentified North American Piogaster male

Figs 22, 23

There is one male specimen collected in 1938 in British Columbia. This male could not be associated with a female or unequivocally determined to be a new species. Geographically, this male is more supported as P. variegata as it was collected ~ 380 km from the type locality of this species in contrast to ~ 1700 km from P. maculata. However, given how little we know about the distribution of North American species, this alone is not evidence enough to associate it. Identification utilizing molecular data was not possible due to the age of the specimen and the lack of DNA of the two other North American Piogaster species which are known only from the holotype. To confidently associate this male with either P. variegata or P. maculata, multiple shared morphological characters are required and were not observed in this study and thus it remains identified only to genus. Nevertheless, we provide a diagnosis and description of this specimen to aid future researchers should additional material be found that will allow clarification with respect to its status. This is the specimen mentioned in Gauld and Dubois (2006) as Piogaster sp. 1. It was reared from Habronattus, providing a new generic host record for Piogaster and, to our knowledge, is the only specimen with associated host remains (Figs 23 E, 23 F).

Diagnosis. This specimen can be distinguished from congeners by possession of the combination of the following: 1) Metasoma with T 1 – T 5 weakly granulate (Fig. 23 C), 2) HW 2 / Cu absent with no apparent bend in 1 / Cu & cu-a (Fig. 23 A); 3) T 6 – T 8 smooth, subpolished (Fig. 23 C); 4) FW vein 2 rs-m short, ratio of 2 rs-m to M between 2 rs-m and 2 m-cu 0.3 (Fig. 23 A). This specimen is most similar to P. variegata and P. maculata with respect to the granulate metasoma and the unbent HW vein 1 / Cu & cu-a, but differs in T 6 – T 8 being smooth and subpolished rather than granulate and matte, and the 2 rs-m vein being short.

Description. Adult. Male. Body length estimated at about 3 mm (specimen in multiple pieces). FW length 2.5 mm. Head. Antenna with 20 flagellomeres. Clypeus 1.9 × as wide as high, matte and granulate, with long white setae. Face and vertex matte and granulate, with sparse (vertex) to moderately dense (face) short white setae (Fig. 22 A). Frons matte and granulate with sparse short yellow-white setae (Fig. 22 C). Occipital carina complete (Fig. 22 D). MSL 1.0 × as long as BWM. OOD 1.3 × as long as LOD. Mesosoma. Pronotum with epomia absent; granulate, with weak longitudinal striations dorsoposterior to the pronotal groove, with sparse medium length yellow setae (Fig. 22 H). Mesoscutum matte, granulate medially, pustulate laterally, with sparse short white setae (Fig. 22 F). Scutellum matte, granulate, with sparse short white setae. Metapleuron subpolished, granulate, with a few sparse short white setae (Fig. 22 H). Propodeum matte, pustulate with sparse long white setae; with pleural carina complete; lateral longitudinal carina present in posterior 0.3, all other propodeal carina absent (Fig. 22 G). Wings. Fore wing. Vein Rs + M with ramellus absent (Fig. 23 A). Vein 2 rs-m 0.3 × as long as M between 2 rs-m and 2 m-cu (Fig. 23 A). Vein 2 m-cu not thickened or angulate between bullae (Fig. 23 A). Hind wing. Vein 1 / Cu & cu-a slightly inclivous, not angulate, with 2 / Cu absent (Fig. 23 A). Metasoma. T 1 matte, granulate, with sparse short yellow-white setae. T 1 dorsal medial carina present anteriorly but weak and short, 0.3 × length of T 1 (Fig. 23 B); dorsolateral carina present anteriorly, 0.3 × length of T 1 (Fig. 23 D). T 2 – T 5 matte to subpolished, weakly granulate, with sparse medium length white setae (Fig. 23 C). T 6 – T 8 subpolished, smooth. T 6 – T 7 with sparse medium length yellow setae, T 8 with sparse medium length medium brown setae. Tergites without grooves or tubercles (Fig. 23 D). Colour. Head primarily medium brown, except the following: clypeus yellow-white; face white with medium brown vertical stripe extending from area between antenna to dorsal edge of clypeus (Fig. 22 A); vertex with triangular pale yellow-white mark (Fig. 22 C). Malar space and ventral gena not paler than rest of gena (dark brown), except just dorsal to base of mandible (Fig. 22 C). Mandible light brown-yellow basally, dark brown apically (Fig. 22 A). Maxillary and labial palps yellow-white. Antenna with scape medium brown dorsally, yellow-white ventrally (Fig. 22 A), pedicel yellow-white, flagellum light brown (Fig. 22 E), slightly darker dorsally than ventrally. Pronotum medium brown anteriorly, pale yellow posteriorly (Fig. 22 H). Tegula white. Mesoscutum medium brown with thin submedial yellow longitudinal stripes (Fig. 22 F) and two anterior sublateral yellow spots (Fig. 22 H). Scutellum medium brown, yellow posteriorly (Fig. 22 F), with axillary troughs yellow-brown. Post-scutellum medium brown and white posteriorly, axillary troughs brown-yellow. Mesopleuron orange-yellow, medium brown ventrally and posterodorsally (Fig. 22 H). Mesosternum medium brown. Metapleuron medium brown dorsoanteriorly, paler ventroposteriorly (Fig. 22 H). Propodeum medium brown (Fig. 22 G). Wings hyaline, veins light brown to transparent (Fig. 23 A). Legs uniformly yellow white, with hind tibia brown-white basally and apically, tarsomeres brown-white, (hind tarsomere not viewed, broken off specimen) (Fig. 22 H). Metasomal tergites medium brown, posterior margins of T 1 – T 6 yellow (Figs 23 C, 23 D). Hypopygium medium brown. Gonoforceps medium brown (Fig. 23 D).

Female. Unknown.

Distribution. Fig. 29. Canada (British Columbia). This is the first record of Piogaster in British Columbia.

Biology. Reared from Habronattus sp. (Araneae: Salticidae).

Material examined. Canada • 1 ♂; BC, Goat River; 24. v. 1938; H. Webb; Rec. B. C. I. A. F. I. Survey 1938; Em. 6. vi. 1938; host: Habronattus (Salticidae) det. J. Pitts 1999; larval exuviae removed slide no. 15. vii. 1999 D. B. Wahl.; CNC 1754420; [CNC].

Condition of specimen: Body on three points. First point has head glued to point on right side (Fig. 22 A). Right antennae is intact, left antennae is glued to same point. Second point has mesosoma glued to point on right side (Fig. 22 H). Third point has metasoma glued to the point on right side (Fig. 23 D). Host on fourth point, glued to point ventrally (Figs 23 E, 23 F).

Comments. This specimen was collected as part of the Forest Insect Survey, a project that ran from 1936–1961 (and continued until 1995 as the Forest Insect and Disease Survey) with the goal of documenting Canadian forest insect fauna (van Sickle et al. 2001). The specimen locality is listed as Goat River, BC. According to the Canadian Geographical Names Database there are three Goat Rivers in British Columbia (Natural Resources Canada 2021). In 1938, 345 of the 442 insect samples collected in British Columbia as part of the Forest Insect Survey were collected by the BC Forest Service (Dominion Forest Service 1939). By accessing archival records of BC Forest Service staff, we determined that the collector of the specimen, H. Webb, was an assistant ranger stationed at Goat River in the Prince George Forest District from April 30 until September 30 in 1938 (British Columbia Forest Service 1920–1964). Therefore, the specimen was almost certainly collected at the Goat River that drains into the Fraser River near McBride, British Columbia, as it is the only Goat River in the Prince George Forest District (Fig. 29). An attempt was made to slide mount the exuvia; however, the resulting preparation appears to be from a sub-mature instar (D. Wahl, pers. comm.). Therefore, the last larval cephalic sclerites of Piogaster remain unknown.