Two-tailed Swallowtail Ecloses

The first of our two post-diapause two-tailed swallowtail chrysalises (Papilio multicaudata) has eclosed. The chrysalises were received in diapause in August from Arizona but must have broken diapause in mid-October.

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Today we witnessed our first ever real life two-tailed swallowtail. Emerging around 2 PM on this relatively sunny afternoon, this gigantic butterfly is this largest we have seen in our life. 

A rough measurement of this individual (a female) was about 5.5 inches. It came from our largest chrysalis which was 2.9 grams before it emerged (that is very massive!). This is larger than any Eastern tiger (Papilio glaucus) or giant swallowtail (Papilio cresphontes), two of the more well known large swallowtails, that we have seen. Although Papilio multicaudata is much less frequently mentioned as being the largest swallowtail in North America, we wouldn't  have our doubts even with our small sample size.   

Compared to the Western tiger swallowtail (Papilio rutulus), the two-tailed swallowtail comes off as being a much more yellow insect since the black stripes on the dorsal side are much less thick in proportion to the yellow portions. P. rutulus actually resembles the anise swallowtail (Papilio zelicaon) quite closely because of its smaller size and higher concentrations of black, but on the other hand you would never mistake a two-tailed swallowtail for an anise! However, the black borders on the edges are the wings seem quite thick and the black stripes on the ventral sides of the wings don't seem to be any less thick than those of P. rutulus. 

After its wings had hardened, we took it outside and took a few pictures. . .

This butterfly doesn't actually have two tails as the name suggests. The scientific name multicaudata is probably more accurate; a quick glance tells us that it actually has four sets of tails. In reality, it only has one true pair, the one seen in most swallowtails, which is much longer than the other three pairs. But because of its overall large wing size, the points at the vein lines on the hind wings (seen in all swallowtails) have been much exaggerated that they are long enough to look like they are tails. 

​As for breeding these things, we are in a very bad situation as of now. The other chrysalis that has been developing doesn't look like it is going to emerge for another few days, and assuming that it is a male we would have to wait another few days for his sperm count to rise before attempting to hand-pair him with the female that eclosed today. If we can get past the hand-pairing, we will need to find a host plant to try to get the female to  lay her eggs on, which will probably prove to be a very difficult task in December. We currently don't really have any of multicaudata's host plants like Prunus virginiana and Fraxinus, and even if we did we would have a hard time finding leaves in this season. Of our two potential options, Klamath plum (Prunus subcordata) and privet (Ligustrum lucidum), the former may be ruled out based on the fact that some studies state that multicaudata is actually selective within the Rosaceae family and will only lay on a few species of Prunus. Privet is evergreen, but it too is highly questionable as a host; it has not been reportedly extensively as a host plant in literature and the only fact backing up the plausibility that it is indeed a potential host is that it is loosely related to Fraxinus (they are in the same family). Then, even if we manage to scrape up something, we would need to provide a warm enough environment to stimulate any activity. It is only about 60 degrees Fahrenheit these days and is only going to get colder in the coming weeks, so this would obviously require a heating system such as a reptile heat lamp. 

- Brian