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Hi,
In my garden there are tiny flies, probably Ceratopogonids, that attack beetles (here they are after an Oedemerid). Some time ago I had a similar thread, but these flies look a bit different. I suppose a genus guess is impossible?
Thanks, Sundew

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Can you describe the attack in more detail?

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Hi all,

I would guess that the ceratopogonids were attracted by the cantharidin of the oedermerid..... this would explain the "attack"..... they just trying to get some of the bettle haemolymph to incorporate the compound for own defense.... species of Atrichopogon are such canthariphilous critters.... but I am not familiar enough with this family to id the specimens on your photos....

so long,
xylo

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Well, Ceratopogonids suck haemolymph of other insects (compare http://www.dipter...ad_id=8720), and their victims "know" that and try to escape. I watched a beetle getting panic when being surrounded by the flies. It kicked and hopped and then flew away. The flies did not follow.
No one is too small to have a parasite of its own!
Regards, Sundew

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Hi Xylo,
our replies crossed! Getting Cantharidine for defense is an interesting point of view and quite convincing. However, the flies suck also on the veins of dragonfly wings, so it is a matter of pure feeding, too, I think. Is it comparable to mosquitoes, that females need protein food to produce eggs and otherwise live from nectar? I don't know...

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Very interesting. Thanks!