Eastern Tiger Swallowtail Chrysalises Arrived

Today our Eastern Tiger Swallowtail (Papilio glaucus) chrysalises arrived. What we plan to do with them. . .

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We failed to successfully get our hands on some of our native Western Tiger Swallowtail (Papilio rutulus) this year, but as of today we have its Eastern counterpart -- Papilio glaucus. Obtained from an Ohio breeder, we now have thirteen Eastern Tiger chrysalises. 

We are always curious to compare swallowtail species. Upon first examination, the glaucus chrysalises are virtually identical to our rutulus. However, these glaucus are surprisingly small, significantly smaller than either of our two rutulus chrysalises that we obtained from captive raised caterpillars last year though it is widely documented that the glaucus is supposed to reach a higher wing span. The largest glaucus chrysalis, a female, is only 1.2 grams with the majority of others around 1.0 grams or less (the smallest was 0.7 grams). They are still small when put side by side with the Anise Swallowtail (Papilio zelicaon) which is supposedly smaller than either tiger; our Anise chrysalises can get up to 1.5 grams in captivity and average 1.1 grams or so. And while we never measured the largest rutulus chrysalises, it was quite a bit bigger than a 1.5 gram Anise chrysalis. Tiny sample size, regional differences, and/or field guide lies. . . ?

Brown morph chrysalises of the machaon group (black swallowtails, or the true papilios by the more conservative taxonomer), such as our Anise Swallowtail, are strikingly similar to the tiger chrysalises; both are bark mimics. However, our Anise chrysalises are much thicker and stoutier and the wing pattern is distinctly different. While the tiger chrysalises have more or less unmarked wings with the dark pattern mainly residing around the perimeter of the wing, the Anise chrysalises have a lot of veins in the middle of the wing. The black on the tiger chrysalises are also much more mottled, or messy as we see it, with the black band along the side always very pronounced. However, the black band along the back is more pronounced in the Anise. 

While they are interesting to look at, the ultimate goal of obtaining these chrysalises was, of course, to breed them. The Eastern Tiger is supposed to be multivoltine in much of its range so we suspect that our chrysalises are probably not diapausing and will eclose soon, especially because one or two of them already feel slightly soft and loose (but not dead, of course). We would have liked if they are diapausing though, because it is so late in the season to rear them. If it takes two months or more for the butterflies to emerge, to hand-pair them, to get them to lay eggs, and raise the resulting caterpillars all the way until they pupate, it will be well into October or even November, by which most of their deciduous host plants begin dropping leaves even in our mild climate. 

The left shows our thirteen chrysalises; the middle compares a glaucus chrysalis (right) with a zelicaon (left); the right compares a rutulus chrysalis (left) with a glaucus chrysalis (right)

- Brian