Dolichopus dorycerus Loew, 1864a

Runyon, Justin B., 2022, Nematode-induced demasculinization of Nearctic Dolichopodidae (Diptera) with five new synonyms, Zootaxa 5092 (5), pp. 545-558 : 547

Dolichopus dorycerus Loew, 1864a

( Figs 1–9 )

Dolichopus dorycerus Loew, 1864a: 93 .

Dolichopus hurleyi Runyon, 2008: 368 , syn. nov.

Nematode. Apparent Mermithidae .

Demasculinized male examined. Holotype ♂ of Dolichopus hurleyi : USA, Pennsylvania, Centre County, Black Moshannon State Park, Moss-Hanne Trail , Shirks Run , 580 m, 18 June 2007, N 40°53.396′ W78°02.584′, JB Runyon, from vegetation in wooded swamp ( USNM) [abdomen partly cut open to reveal mermithid-like nematode within].

Remarks. The demasculinized male has smaller than normal genitalia (cf. Figs 1, 2 ) that are held off-center beneath abdomen, a less-well developed lamella on arista (cf. Figs 3, 4 ), wider silvery face (cf. Figs 7, 8 ), and lacking costal enlargement at apex of R 1. MSSCs of the legs that are lacking include the longer black setae on posterior surface of front femur and the slightly raised, minutely pilose area on posterior surface of the hind tibia (a characteristic of this species group). Notably, the size of lobes of the modified front tarsi are reduced with tarsomere 5 wholly black (mostly white in normal males) (cf. Figs 5, 6 ). Numerous normal males of D. dorycerus were collected at this site with the single demasculinized specimen.

Figures

FIGURES 1–6. Comparison of normal male of Dolichopus dorycerus Loew versus male infected by mermithid-like nematodes. 1. Habitus, normal male. 2. Habitus, infected male. Note smaller genitalia and smaller size of modified front tarsomeres. 3. Antenna, normal male. 4. Antenna, infected male. 5. Front tarsomeres, normal male. 6. Front tarsomeres, infected male. Note smaller size and lack of white on apical tarsomere.

FIGURES 7–15. Effects of mermithid-like nematode infection on faces of male Dolichopus species. Normal males (left column), infected males (middle column), and females (right column). 7–9. Dolichopus dorycerus Loew. 10–12. Dolichopus partitus Melander & Brues. 13–15. Dolichopus sincerus Melander.