Flies Hanging on to Plants

Every year, I see green bottle flies hung over the ends of leaves or tall stems, and I’m wondering why? I’ve seen similar from ants with the ophiocordyceps, but the flies don’t seem to have a “fungus stalk.” They just seem to latch on and die. This seemed more prevalent last year, but I’ve seen some this year as well.


(Sorry in advance of the picture is bad.)

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See fly death fungus: https://www.inaturalist.org/observations?taxon_id=339550


Most of the ones I’ve seen like this are infected with a different fungus than the various Ophiocordyceps / Cordyceps flavor. This type doesn’t make a stalk, but rather gets the fly to perch on an exposed spot and then when it converts to spores they’ll have a good launching pad. Similar to https://en.wikipedia.org/wiki/Entomophthora_muscae, I don’t know how much diversity there is in this syndrome. I’d imagine that sometimes the fungal infection might fail (and thus not make clear hyphae) even though the fly dies.


Thank you for the quick responses! What I’m getting from this is that it’s most likely a fungal disease affecting the flies.

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Yes it is.


I can’t quite tell from this photo, but it looks like the wings might be pushed forward. That’s also typical of this group of entomopathogens, enabling the fungus to disperse spores from the abdomen. The mechanism isn’t quite understood, though, because it happens after death.


In the photo, I believe the wings are pushed forward, though there is a slight possibility that it could’ve been due to external forces (such as rain and wind). It’s been raining a bit for the past couple of days. Either way, thank you for the additional information!

The more I learn about arthropods, the more I realize our human diseases actually aren’t that bad.


Sometimes it’s only visible at the intersections of the exoskeleton, as in this cicada infected by a cordyceps fungus in Vietnam:

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Difficult to make out …and maybe not important…but not convinced this is a greenbottle…at least not in the UK use of that common name ( Lucilia sp.)

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I’ll try to find a “fresher” fly next time I go out. Hopefully, the abdomen will be more visible.

What type of fly do you think it might be? I’m not to good with them.

difficult to make out and given the impact of fungi or whatever it is, some characters are unreliable - the head looks either small or no longer there, but taking it at face value and ignoring impacts of decay, it looks more like Acroceridae or similar to me… (it appears to have an unusually small thorax relative to the abdomen)

not seen blue-green ones like this in Europe, I see though that there are blue-green ones in the US

also unclear to me what part of body the upper portion is though(?)…so … maybe I´m just missing something entirely…

but in any case, whatever it is…if it was Lucilia or another calliphorid, I would expect it to have calypters visible, even in this sort of decayed state

Anyhow …all discussion to better have on the observation itself with other more local identifiers probably ! ( you should log it if you haven´t already )


Poor thing!

Is this insect also infected by a fungus?


I don’t know. It looks like a Speckled Bush-Cricket (Leptophyes punctatissima) nymph but it also looks like it’s having some problems.

Not sure what’s going on with it. Could be a mutation, could be a parasite (fungal, insect, or otherwise), or something else entirely.

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Here’s the observation on iNat


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Not that it matters too much, but I found another, fresher fly. This time, on a lavender.

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