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Imagine that on most of the umbelliferous flowers on a field:

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Anyone knows the sp?

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Right now there is a plague of Sepsis spp.. In some Poaceae plants we can see hundreds and hundreds of them. I dunno why. :| This was the first time I've seen this phenomenon.

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Yes, usually they are quite territorial (at least the males, I suppose)

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yep, but with so many members,. (hundreds) I never saw such thing until this week. Usually I found them in dozens or so... but never in hundreds...

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this was taken with a bridge camera... in Sunday.

As you can see the plant (only a part of it!) has a plague of Sepsis sp. :|

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another taken with the same bridge camera.

now you can count these sepsid flies. :) You can begin now. :D

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And here a video:

YouTube Video

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Sepsis fulgens is know to form aggregations of hundreds up to thousands of specimens, usually later in the year. The aggregations may persist for quite some time and ay be accompanied by a distinctive smell. Adrian Pont wrote a paper about it. I'll see if I have it somewhere.

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here :D

http://books.goog...mp;f=false

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It was a paper dedicated to this phenomenon only

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if possible, upload the pdf file for DI... ;)

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I checked the collected material and found a male :) Anyone for a Sepsid-ID?

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I was searching the web to see if I could track down a pdf of the Pont paper on Sepsis swarms referred to in this thread. Did anyone manage to get hold of the pdf - if so, would they mind passing on a copy to me?

The male above looks as though it might be Sepsis fulgens.

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The ID is correct.
Of the paper I only have a hard copy.