Albany, California Updates (8/22/17): Papilio rutulus Data; Citheronia regalis Pupae; Machaon Swallowtail Update

Well, it's been a few days since we have arrived in Ithaca and there are numerous rearing projects still in progress back home in Albany that we no longer have direct control of anymore. Fortunately, our mother has agreed to help take care of anything that are require immediate attention, at least for now. With that said, from now on we will periodically post updates on any significant events that take place in Albany as they occur and are reported to us. 

The first update is for Papilio rutulus. On the day that we left (August 16), there were still three stragglers left, including two that were unusually small and probably unhealthy. We had left the three together in a tub in darkness with heaps of willow (Salix) cuttings to ensure that they would not starve for the five days that nobody would be at home. At the time, we actually suspected that they would stop feeding before the five days, and we were correct; two of the three have already pupated into 1.08 and 1.45 g pupae and the last one is a prepupa. The 1.45 g one is quite surprising, placing fifth of 26 in weight, and was most definitely the one of the three that was not sickly. . . On the other hand, the 1.08 is third to last. The one thing to note, however, is that these weights were not necessarily taken right after pupation (well, within 24 hours), which was the procedure we used to collect all of the other data points.

The second update is for the regals (Citheronia regalis). Before we left, we were hoping desperately for the things to pupate so that we could just see it once before the rare opportunity would be lost. Unfortunately, that never happened, even after five days of being in the prepupal stage inside the incubator. In the end, it is not unreasonable for earthen pupates, especially such massive ones as these, to take an absurdly long time to pupate, but of course it was still a major disappointment. At some point during our leave, five of them did finally pupate though at 6.6, 6.62, 7.0, 7.13, and 7.94 g (again, these weights are probably slightly less than they would have been if they were taken immediately after pupation). While not unimpressive relative to other species that we have reared, these weights are still somewhat disappointing for how large the caterpillars were. Based on old records, they roughly shrank to just above a third of their peak larval weight, which is a pretty steep drop compared to most other things. Although we have not received any pictures of them yet, our mother assures us that they do not suffer from any deformities, which is a great relief given how difficult it often is with earthen pupators. 

Lastly, we come to the various machaon swallowtails, which all decided to come at the worst possible time. . . In the days before we left, we had very hastily created some hybrid pairs of P. polyxenes asterius and P. zelicaon and left what we hoped were fertilized females outside in the cage to lay eggs. After five days, all but one of these females is still alive and, according to our mother, there are no fresh eggs. Right now, it looks like we have failed this time. But hopefully we will be able to try again, now that we have easy access to P. polyxenes asterius here in Ithaca!

Update: The last rutulus pupated at 0.95 g. The collective average for the rearing is 1.258571429 (n = 27). 

---

Authors
Brian Liang

---