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 Bibio males -> johannis
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| Sundew |
Posted on 11-05-2020 22:57
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 Member Location: Posts: 3890 Joined: 28.07.07 |
Hi, These small Bibio males drive me crazy! Many of them sit around on the grasses, females are not seen. I tried so hard to find a B. varipes male for my female (https://diptera.i...d_id=94658) but the result is frustrating... The males I checked seem to belong to the same species. I even translated the key by Verbeke (1971) to not overlook a helpful character, but the flies key out as B. johannis. They are red-legged, and the hairs of head, thorax, legs and body are completely black. Though I find the wings a bit brown and the metatarsus III a bit long for johannis, I think I recognize a johannis character of tibia III: a longitudinal row of black dots on a brown stripe (the latter being not mandatory). I marked it with an arrow in the first picture. I took two series of photos, one without flash light to avoid reflection (but of less quality then) and one with flash. The locality was the same: southwestern germany, about 20 km west of Stuttgart, edge of a small wood. This is the first male from May 5th, without flash. Edited by Sundew on 12-05-2020 11:26 |
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| Sundew |
Posted on 11-05-2020 23:00
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Member Location: Posts: 3890 Joined: 28.07.07 |
Here is the second male from May 9th, photographed with flash light. Can there be any doubt about B. johannis? Thanks for discussion, Sundew |
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| Zeegers |
Posted on 12-05-2020 07:35
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Member Location: Posts: 18446 Joined: 21.07.04 |
Hi Sundew, Did you check Haarto's (2012) key for Finland (W-Album 12) ? The row of dots on posterior side of hind tibia are sensoria, according to him. They don't need to be black (my collection). That said, they are lacking in lanigerus, so it seems you independently rediscovered an important feature for johannis. Please note that colouration of legs is extremely variable: even femora can be totally red in johannis. So, it seems you are right, despite the fact that the date is extremely late for johannis. In NL, I would never find johannis after May 5th. Greetings Theo |
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| libor |
Posted on 12-05-2020 09:07
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Member Location: Posts: 1266 Joined: 30.05.09 |
In my region, westernmost parts of Czechia, is Bibio johannis trapped egularly up to mid of May, my two latest records are from 21th May. Sundew, can you send me your translation of Verbeke's key? Other language could be better for me ;-) Greetings Libor |
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| Sundew |
Posted on 12-05-2020 11:25
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Member Location: Posts: 3890 Joined: 28.07.07 |
Well, my dear fellow bibionists, I am happy that we all agree on B. johannis! Theo: you are much too kind, I did not "rediscover an important feature". Verbeke describes that row of dots for johannis and says that in varipes and lanigerus the black dots are more spaced or less conspicuous and in any case do not form a continuous longitudinal row. - The hint to Haarto (2012) was very valuable. I found the paper online, and it looks very comprehensive, thanks! Interesting to know that this dark row of dots is formed by sensillae. Libor: I'll send you an e-mail. Last night the temperature was very low, there was white frost on the roofs in the morning. I wonder if the Bibios endured it. My search for B. varipes continues! - BTW, according to Haarto B. johannis flies in Finland from mid May to mid June. Obviously the flies leave NL after May 5th to arrive in Finland in time  Best wishes, Sundew |
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| Zeegers |
Posted on 12-05-2020 14:53
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Member Location: Posts: 18446 Joined: 21.07.04 |
B. varipes tends to be rather solitary. Those clouds of Bibio are johannis, lanigerus or sometimes nigriventris, but I never found varipes in these clouds. Varipes is more a woodland species. Here, in NL, johannis is the first to appear, from the first day of april or even end of march. These regional differences are stunning (and confusing). Theo |
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| libor |
Posted on 12-05-2020 19:46
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Member Location: Posts: 1266 Joined: 30.05.09 |
Here, I found more times Bibio varipes in mass numbers. (1) 3 MM and 37 FF, ( 30 MM and 5 FF, (C) 23 MM, 5 FF and more times in numbers around 15-20 specimens. It seems that every features concerning Bibio occurrence are applicable based on geographical areas...Libor |
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| Zeegers |
Posted on 13-05-2020 07:07
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Member Location: Posts: 18446 Joined: 21.07.04 |
Yes, indeed, impressive. So to all my posts the disclaimer: based on dutch experience. Thanks ! Theo |
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but don't see the image in the post.