Multiple adults from the same larva

I’ve just read a book that claims sometimes when a larva pupates in some insect species it’s possible for more than one adult to emerge, the particualr example given is the fungus gnat and such an occurance is described as polyembryony.

I’m slightly sceptical about this, but sort of hope it’s true as it’s a nice fact. Also polyembryony would seem to refer to the egg rather than the pupa.

I don’t know if it’s true that there are such cases, but it seems like it should be technically possible. When insects pupate, the remains of the larva are pretty much digested to feed the growth of a few small clumps of cells that have remained dormant though the larval stage - and these grow into the adult insect - it’s almost a completely new animal.

For some reason, that really freaks me out.

Cite?

I’m not an entomologist, but what I find from a brief search seem to add up to pupating insects developing along similar lines to the ones undergoing partial metamorphosis. I.e. gradual changes in the whole body leading from one body form to another. See for instance the gradual change from wasp larva to wasp in the wikipedia article on holometabolism: Holometabolism - Wikipedia

This is also my impression. I think what the book might have been referring to is paedogenesis, where some insects like fungus gnats and gall midgescan reproduce as larva or pupa. From the wiki page:

Yep, the passage in the book mentions this specifically. I.e. how the body of the larva is mostly broken down by digestive juices leaving only a few cells to divide and become the adult.

It’d be :cool: if you could go from one animal larva to two animal adults, but I just can’t find anything to back it up. In some ways I suppose it’s not that different from very simple animals like for example planarians which are able to regenerate two animals from one animal if cleaved in half.

I think the book also describes paedogenisis, so I don’t think they’ve got them mixed-up. The book itself seems to fairly accurate (when I’ve checked some of the other parts of it)however given the author is certainly no more of an expert on biology than me I would not take anything in it as gospel without confirmation.

Could this be the bookyou’re refering to? I can’t say for sure that they’re wrong but I haven’t been able to dig up any information about metamorphosis from one pupa into multiple adults. I highly doubt that it would be refered to as polyembryony in any case. I would think that there would be at least some studies as imaginal discs is an important topic in developmental biology. The ability to reproduce asexually in the pupal stage would be a pretty big deal.

I did found some references to polyembryonic or gregarious parasitic wasps whose larvae lives in and feeds off fly pupae, eventually emerging from inside the host. I doubt that’s what they meant but it was the only link between polyembryony and pupation I could find.

Although I said above that it sounds technically non-impossible, in practice, it seems maybe a bit unlikely - because I think the imaginal discs are in specific places in the larval form, and they’re configured to produce different adult structures - so it seems a bit of a leap for them to be configured and placed to form multiple adults, at the time when they’re present in a single larva.
But one possibly plausible evolutionary step might be a mutation causing each imaginal disc to be able to differentiate into the whole gamut of cells necessary to form a complete adult body.

Insects have been evolving a long time, and with short generation times, they’ve had plenty of opportunity to try all sorts of different strategies and variations - so it shouldn’t surprise us too much to discover considerable variety in the way they do certain basic things, such as reproduce and develop.