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Hey, caught this male indoors in January. Help with determination very much appreciated.

More pictures can be found here:
https://www.inatu...ns/9373577

Best,
Lorin

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Hercostomus, maybe rusticus

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Carnifex,

I see that you found this indoors in January. I am puzzled. Wild doli in Austria I would expect to be hibernating in the winter. Do you have a greenhouse or indoor plants where this may have emerged from the soil?

Kind regards,

Keith Short
Northern Illinois, USA

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Thanks Igor, for the determination.
I would like to identify it further, if possible. Such a large genus, though... :o


Dear Keith,

I just have normal potted plants, one of which was kept outside in the garden until late autumn.

I caught two specimens, a male and a female, within two days. Unfortunately the female escaped before I could investigate it. Was hoping for more to find, didn't happen.
Do you think the adults were overwintering or there were larvae developing in the soil?

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it is not over yet: Today (Feb 1st) I caught a female, indoors again.

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Dear Igor,
both specimens key to species-group IV (femora black; lower postocular setae white).

I noticed that you published quite a lot about this genus, unfortunately most of the articles I have no access to. However, in the "checklist and keys to Dolichopodidae (Diptera) of the Caucasus and East
Mediterranean" both of my flies, male and female, key perfectly to H rusticus:

Male - Calypter with black cilia; Postpedicel twice as long as broad; hind basitarsus shorter than 2nd
Female - Calypter with black cilia; Postpedicel 1,5x longer than broad; hind basitarsus shorter than 2nd

I wonder if you know if there are any Middle European species that, based on these features, can be confused with H rusticus.

Best, Lorin

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Dear Keith,

I moved the potted plant into another room, and now the flies appear there. So they might in fact come from the soil.
I found this article (in German) about phenological appearances of Dolichopodidae in Switzerland, and there have been some cases of Hercostomus rusticus in Dezember and February.

http://www.zora.u...ntHelv.pdf

Cheers!

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Hey, would like to put this thread on the agenda again :-)
Still do hope the species can be IDed to species level