Comparing the Chrysalis of P. zelicaon and P. machaon oregonius

Now that our Oregon Swallowtails (Papilio machaon oregonius) have pupated, we have the chance to compare them to our Anise Swallowtails (Papilio zelicaon), another machaon group swallowtail. 

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From the moment we first got a good look at our first Oregon Swallowtail (Papilio machaon oregonius) to pupate on 9/21, we already got the sense that this phenotype was not your typical Anise Swallowtail (Papilio zelicaon) which we are much more used to seeing. 

For one thing, the oregonius chrysalis was huge: 1.3 grams for a male individual (on average, the smaller sex). 1.3 -- even 1.2 and some 1.1 -- gram Anise Swallowtails  are invariably female and the average Anise chrysalis including either gender straddles between 0.9 and 1.0 grams. Of 262 Anise chrysalises we had in August, only one chrysalis was larger than 1.3 grams at 1.5 grams; and there were only 11 1.3 gram chrysalises. Using these numbers, the percent of Anise chrysalises at or above 1.3 grams was only 4.58% (and we are quite confident that these were 100% female). While this is only one oregonius chrysalis we are looking at, the odds are highly in its favor that the oregonius are the larger species. 

While we had the feeling that the Oregon chrysalis didn't look quite like an Anise chrysalis (ignoring size), we couldn't quite put our fingers on it until today when the chrysalis fully tanned. Immediately, we noticed that the color was a bit off. It was a brown or dark morph chrysalis with a palish base and black stripes. While Anise chrysalises can also have a similar coloration, they are often much more mottled with the dark and light parts blending (sometimes looks brownish). Because we couldn't find a single exact match to the Oregon coloration out of our 70 or so brown morph Anise chrysalises, we took the closest match to do a side by side comparison. One obvious area of difference is in the wing pattern; the Anise chrysalises consistently have thicker and darker vein lines but reduces markings at the outer part of the wing as compared to the Oregon.

P. zelicaon

P. m. oregonius

Another major difference between the Oregon and the Anise is the bump that protrudes from the back at the thorax. In the Anise, the bump is larger (wider) and is pointy (looks kind of like a horn jutting out) while in the Oregon it is more blunt. 

P. zelicaon

P. m. oregonius

A third big difference is the horns on the head. Like with the thorax bump, the horns of the Anise are noticeably more pronounced and wider.

P. zelicaon

P. m. oregonius

Overall, the Anise also seems to be thicker and perhaps shorter (more stout) throughout the body. (Normally, females tend to be thicker than males, but in this case the Anise we used was also a male.) To make this more dramatic, the Oregon's legs and antennae stretch further down the length of the wing. 

P. zelicaon

P. m. oregonius

- Brian