What happened to this moth?

Hello, I didn’t know where else to post this so I put it here. A few weeks ago I found this moth in the middle of a bridge. When I picked it up from the ground, I noticed a strange thing under it, at first I thought it was some kind of dirt like a leaf or something. I tried to take it off but it seemed like it was stuck to it. That thing next to her leg causes me curiosity, it’s not part of her leg I think. I don’t know what else it could be, does anyone know?


an emerging parasitic wasp?


To me it looks like it suffered an injury somehow and its insides have spilled out a bit? It looks like it originated from the abdomen. May have happened when the moth has just eclosed and was crawling up to higher ground.


Doesn’t look like a parasitoid, the structure is too irregular. I’m guessing it’s either a dried organ or the animal mispupated and is teratological (nongenetic post-pupal deformities are frequent in insects sometimes).


Amazing! I’m impressed by your observationalitude (observiness? observirtuosity?). You observe real good.

There are fungi that will grow out of live insects. I do not think that is necessarily what this is, but it is another possibility to consider.


After seeing the third picture, my impression was of a pupal exoskeleton not properly detached.


Yeah, I’m sure that’s what it is. And that ‘leg’ is a malformed hind wing. It’s not uncommon for moths to emerge from the pupal case with malformations of some sort. Whether there was an external cause or just problems emerging is hard to tell.
EDIT - I take the hind wing thing back. The hind wing is intact. This is some sort of growth. There is a similar spot on the wing and the lateral abdomen. These could be developmental abnormalities: a problem during the change from larva to moth, a genetic abnormality of unknown causes. I doubt it is parasitic - they generally emerge in the larval stage, and the rest of the moth looks fairly normal and healthy.


Those are pretty impressive photos of an interesting phenomenon. Thanks to all who contributed explanations, too… fascinating.

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