Diptera.info :: Identification queries :: Diptera (adults)
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 Again: Rhagio
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| Juergen Peters |
Posted on 09-08-2006 23:59
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 Member Location: northwest Germany Posts: 13957 Joined: 11.09.04 |
Hello! Some days ago I posted a Rhagio strigosus. Also at night the Rhagio males come to light at the same place in our garden (Ostwestfalen, Germany). At first I thought, they were also R. strigosus. but the one on the first two pics has a red thorax and a little bit shorter forelegs than the one on the third photo. So I think, they are different species (?). Thanks for any hints!   
Best regards, Jürgen -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Juergen Peters Borgholzhausen, Germany WWW: http://insektenfo... -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= |
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| Tony Irwin |
Posted on 10-08-2006 09:22
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 Member Location: Norwich, England Posts: 7236 Joined: 19.11.04 |
Hi Juergen The first two are females, and the third one a male. The thorax colour in strigosus can vary. As for leg length, I think this is a matter of perspective - the male appears to have forelegs of different lengths, but it is just the way that it is sitting. My feeling is that these are all strigosus. Tony ---------- Tony Irwin |
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| Juergen Peters |
Posted on 10-08-2006 19:26
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Member Location: northwest Germany Posts: 13957 Joined: 11.09.04 |
Hello, Tony! Tony Irwin wrote: The first two are females Oh! With those large eyes narrow together I thought they were males. and the third one a male. The thorax colour in strigosus can vary. As for leg length, I think this is a matter of perspective - the male appears to have forelegs of different lengths, but it is just the way that it is sitting. Possibly it was also because it used its long forelegs like antennae for groping. My feeling is that these are all strigosus. Thank you very much! Best regards, Jürgen -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Juergen Peters Borgholzhausen, Germany WWW: http://insektenfo... -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= |
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| Tony Irwin |
Posted on 10-08-2006 21:07
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Member Location: Norwich, England Posts: 7236 Joined: 19.11.04 |
It interesting you mention the groping - many flies with long forelegs do this. In Hymenoptera and Coleoptera, feeling with the antennae is common, but in flies (even those with long antennae) it is very rare. In Rhagio the females' eyes are large, but separated by at least the width of the antenna. The males have eyes that touch or nearly touch (in latipennis they are separated by the width of an ocellus). Your lower two pictures show the difference between the male and female abdomens very well. The female segments get progressively smaller, ending up with a very small terminal segment bearing the anal cerci. The male segments are more the same size, and end up with a complex genital apparatus. This is true for most flies, but in many families, the females have evolved specialised ovipositors, or they retract the terminal segments so they are difficult to see. And in some families the males have very small genitalia, so it is difficult to tell them from females by looking at the abdomen. (Not as difficult as Coleoptera, though!  ) It all adds up to a lifetime's study! 
Tony ---------- Tony Irwin |
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