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Bound fly - Pollenia

Bound fly - Pollenia
Bedford, Westchester County, New York, USA
July 26, 2005
I found several of these bound flies in an area in my yard. Does anyone have any idea who does this kind of thing?

Images of this individual: tag all
Bound fly - Pollenia Bound fly - Pollenia

Moved from Unidentified Fungus-ridden Flies.
Identifiable fungus-ridden flies are now being moved to their proper places, since there is a gallery of all the fungus-ridden insects here.

Moved from Cluster flies.

This looks like a Pollenia species with those curly gold hairs on the thorax.

not sure why you frassed these. We think it would be nice to keep at least this one for the image and the discussion. Can we move this one over to the fly page?

John and Jane,

Sure that would fine. I wasn't sure what to do with them because there was no id. Can't say I've got the whole procedure figured out yet.


Fungal infection
These flies are killed by a fungus that has an extraordinary life cycle in flies. Before death the fungus actually seems to induce the dying flies to climb to prominences where they can be seen by other flies. The male flies (and I have been told that only the males are infected) are bloated by the infection giving the appearance of a female fly burdened with eggs. When the next male attempts a sexual contact with this exposed fly the fungus is transferred to another victim. Who then continues the cycle after his infection progresses to the point where he climbs to another prominence and dies exposed and waiting.

Thanks for this explanation!
I seem to have some photos that go along with this theory:

This is amazing. I was 'just' researching this for my field guide this morning! The fungus is Entomophthora muscae, and afflicts many families of flies, including Calliphoridae, Syrphidae,Sarcophagidae,Scatophagidae,Dropsophilidae,and Culicidae.

Hi Hershel,

Second time you've answered a question of mine. Thank you very much. That's a pretty diabolical fungus. Does it only occur in this species (whatever this this is?)?.


Whatever it is, is right. I don't think the fungi are specific to one group of flies and certainly not one species. And I would need to get a fungi expert to answer whether this is a large group of fungal species or just one doing the dirty work.

Amazing fungus
It's really amazing. I was telling my wife about it and she thought you were pulling my leg. There's a really bizarre type of intelligence to to the whole process. Very creepy sci-fi type thing.

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