Confused 4th instar A.ilia larvae, pupating!

[irisscientist]

Over the last couple of days I have just witnessed a confused 4th instar A.ilia larvae position itself in the characteristic 'head down' posture and subsequently attempt to pupate. The outcome of the shedding transformation is nothing other than fascinating, presenting with a mutant specimen which is half larvae, half butterfly. The dorsal surface of the specimen is certainly more reminiscent of the pupae/butterfly, whilst the ventral surface is certain more characteristic of the larvae. The head and thorax sections are particularly interesting. From the larval cephalic larval horns the antennae have partially developed, whilst the larval jaws remain the butterfly mouth parts have also developed including a stunted proboscis. The larval pro-legs remain, although these have been spatially repositioned characteristic of an the adult butterfly. I think we could safely say that the homeobox genes in this particular specimen have certainly become rather mixed up! I have attached some images for those that are interested. Has anybody else had experience with such a 'confused' specimen?


Mark

[saye]

What an interestingly grotesque thing. One question: is this species larva a four staged one? That would make a difference. If this happened in the penultimate instar then it is extra bizarre. However, by "cephalic horns" do you mean the protuberances so characteristic of the genus? Are you sure there's a relation between those structures and the development of antennae? I also cannot spot the prolegs in the images.

Radusho is saying that it's (all) about ecdysis gone wrong - indeed, stressed pre-pupae and newly formed pupa can produce malformed adults. While you (irisscientist) point out mutated genes.

Either way, this is quite odd to me.

[antheatre]

Very interesting! I had a similar experience with a couple A. polyphemus larva about two years ago. They were L5 larvae fed on Liquidambar and when it came time to pupate, their prolegs remained.

[saye]

This beckons the question(s): did they die afterwards? Could they have possibly remained alive and eclosed in time?

[antheatre]

Neither of these pupae survived. They had, in fact, died a couple weeks later. I should add that these pupae were a couple weeks old at the time of taking the photos and their prolegs were still soft and appeared somewhat functional still.