Revision of Nearctic Stylogaster (Diptera: Conopidae)

Abstract

Nearctic Stylogaster Macquart (Diptera: Conopidae) species concepts are revised. We provide redescriptions of S. biannulata (Say) and S. neglecta Williston, description of S. beresfordinew species, an illustrated key to species, range maps, and ecological data. Stylogaster beresfordi ranges from southern Mexico to southern New Mexico, United States of America. DNA barcode data are provided with neighbour-joining and Bayesian analyses and relationships of the three species are discussed. We hypothesise that S. neglecta and S. beresfordi are sister taxa, while S. biannulata is in a different clade.

Oecanthus nigricornis(Orthoptera: Gryllidae) as the first known host ofStylogaster neglecta(Diptera: Conopidae)

“…Stylogaster neglecta appears to parasitise hosts from late July to early August and is not active throughout the rest of the summer. This is consistent with unpublished adult collection records associated with the Burt et al (2015) revision, which examined records of adult S. neglecta in collections across North America. Of the 128 S. neglecta caught in southern Ontario, eight were caught in June, 114 in July, five in August, and one in September.…”

“…Stylogaster species have been studied mainly in Africa and the Neotropics and are associated with army ants (Hymenoptera: Formicidae), using hosts that have been flushed out by the ants (Lopes 1937;Rettenmyer 1961;Burt et al 2015). The flies are thought to either stab their ovipositors into the abdomen of the host and insert the egg under a sclerite or shoot the egg from the ovipositor via a flipping motion of the abdomen (Kotrba 1997;Woodley and Judd 1998).…”

“…The flies are thought to either stab their ovipositors into the abdomen of the host and insert the egg under a sclerite or shoot the egg from the ovipositor via a flipping motion of the abdomen (Kotrba 1997;Woodley and Judd 1998). While most studies have focussed on tropical species, Stylogaster neglecta, S. biannulata (Say), and S. beresfordi Burt are found in the Nearctic region (including Canada), typically in forest understoreys where adults feed on yellow/white flowers (Burt et al 2015). Only S. biannulata has a recorded host, Gryllus rubens Scudder (Orthoptera: Gryllidae) (Woodley and Judd 1998).…”

“…We collected further O. nigricornis samples at the University of Toronto at Mississauga (Ontario, Canada) in the summer of 2017 and 2018 and identified emerging adults as S. neglecta using Burt et al (2015). In 2017, O. nigricornis were collected from natural populations at discrete time intervals to determine when in the season conopid parasitism occurs.…”

Stylogaster eggs on blow flies attracted to millipede defence secretions in Tanzania, with a stab at summarising their biology (Diptera: Conopidae & Calliphoridae)

“…The females search for potential hosts in front of the leading edge of the advancing raids, looking for potential hosts fleeing from the ants (Stuckenberg 1963, Smith 1967, Smith 1969, Smith and Cunningham-Van Someren 1985, Kotrba 1997, Couri and Pont 2006, Couri and Barros 2010. When not following army ants, adults of Stylogaster can be found hovering over sunlit paths in the forest understorey or feeding off the nectar on small white or yellow flowers (Rettenmeyer 1961a, Burt et al 2014. The few hosts that are confirmed from actual rearing of Stylogaster specimens are all crickets and cockroaches (Smith and Cunningham-Van Someren 1985, Woodley and Judd 1998, Etzler et al 2020.…”