Limenitis chrysalides (continuation)

[lamprima2]

A while ago, I posted a question on the possible function of
a flipper-like outgrowth on the base of the abdomen of Limenitis lorquini
chrysalides. Since then, the leps have eclosed. Both sexes have a cluster
of elongated setae on the base of the abdomen, corresponding to that flipper-like
structure of a chrysalis. Any thoughts about the possible function of these setae?

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[Chuck]

And nobody has ever noticed this???

[adamcotton]

Interesting. Presumably this 'hump' occurs in both sexes, if so it is not androconial.

Adam.

[bobw]

Yes Adam, both sexes ... and I believe in all Limenitis, certainly in the 4 or 5 species I've reared.

[Chuck]

Liminetis arthemis pupae also have this, anyone have adults handy to look at/ photo?

[adamcotton]

Igarashi & Fukuda (2000 - The Life Histories of Asian Butterflies vol. 2) illustrate pupae of several Asian Limenitis species, and those all have a similar 'hump'. Interestingly, illustrated pupae of Athyma species have a similar protruberance, but rather more ornate. Lebadea and Moduza species also have it, but somewhat smaller.

Adam.

[Chuck]

I checked my wild-caught arthemis, astyanax, and archippus. The abdomen is humped there, though few have much in the way of a tuft of hair. I wonder if it's a wear item that gets lost with age/ use. But the astyanax and arthemis, at least, have a consistent hump, which I'd have just written off as the way it dried. Interesting.

[lamprima2]

Interestingly, even the larvae of Liminites have a "hump", which is roughly corresponding to the “flipper” found in chrysalides and the cluster of setae in adult butterflies. Here: Full-grown larva of the red-spotted purple Limenitis arthemis astyanax (Fabricius). Photograph by Donald Hall, University of Florida (from https://entnemdept.ufl.edu/).

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[Chuck]

Surely, somebody must have studies and published on this hump. Right? It is rather obvious. I mean, we have people publishing on Tortricidae, and this is far more interesting.