Return to Albany, California (Winter Break 2017-2018): Papilio zelicaon; Battus philenor hirsuta; Smerinthus opthalmica

We have returned to Albany, California from Ithaca, New York as per Cornell University's winter closing, giving us a chance to check on our overwintering pupae.

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Although we have generally been unimpressed by the insect diversity in the Bay Area, it is hard to deny that we are concerned about the loss of stock of a few major species that we did have access to in Albany, California and not in Ithaca, New York. As of this winter break, we still maintain a decent number of wetern tiger swallowtail (Papilio rutulus) pupae, reared from the summer, as described in this recent post; these are probably the most important considering how difficult it already would be to maintain a stock of them even if did not have to leave to Ithaca. As for the other native species, we still have a handful of anise swallowtail (Papilio zelicaon) pupae reared or collected by our mother while we were in Ithaca, a fair number of pipevine swallowtail (Battus philenor hirsuta) pupae from larvae reared in summer, and a large number of Smerinthus opthalmica pupae also from larvae reared in the summer. 

It is especially important that we maintain this stock of anise because they are something that we could conceivably rear in Ithaca and would be very difficult to obtain otherwise (from other breeders). Further, if we encounter P. polyxenes asterius at some point in Ithaca, it would be a grand opportunity to conduct further experiments between the two, including hybridization. The main problem right now is that, at least historically and when reared in captivity, this local stock has proven to be quite poor in the execution of the winter diapause. Already we have thrown away a significant number of dead pupae while inspecting them today and can expect their numbers to continue to steadily decline before a chaotic emergence sometime in the spring. In fact, we have never had a huge success with breeding these from overwintering pupae and have always much more on collecting eggs as they appear in the wild in order to reinvigorate the colony. Nevertheless, the pupae that we have now are certainly better than nothing and if worst comes to worst, we can ask or mother to collect eggs for us as we still have fennel (Foeniculum vulgare) growing in our yard in Albany. 

The pipevine pupae arguably suffer an even higher diapause mortality rate (and losses from stray emergences) than the anise since most of them already enter diapause very early in the year. Less than half of what we initially had in June have made it to this winter break. The good thing is that, although they are one of the few species truly unique to our time in Albany (most other species at least have a regional counterpart in Ithaca), our hopes of breeding these was never high, so we will not concern ourselves too much with them. In the past, we have never been able to get the females to lay eggs in captivity, and even if we somehow managed to do it, we do not have easy access to live pipevine (Aristolochia spp.) plants  in Albany or Ithaca. Even if we were to stay in Albany, the most logical thing to do if we really did want to continue rearing them would be to just collect a fresh stock of them come Spring where the eggs and larvae are extremely easy to find in big numbers; the same cannot be said of the eggs and larvae of the other native species mentioned in this post. 

The opthalmica, like the rutulus and anise, are very important. Not only are they the easiest of the three to breed, both in Albany and in Ithaca, we also have the largest number of them (200+), even after finding a few dead ones and one that had been fed on by some sort of flesh-eating fly larvae (presumably not parasites). We can afford to make mistakes with these so we are considering risk-splitting them with several treatments: some we will overwinter in the refrigerator, some we will keep outside, and some we might bring over to Ithaca. 

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Authors
Brian Liang

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