Return to Albany, California (Winter Break 2017-2018): Papilio rutulus

​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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This is the second in a series of posts that we will be making to address each of the species that we are still keeping in Albany, California, now that we are physically there over winter break, that will be covering the western tiger swallowtail (Papilio rutulus) pupae from larvae that were reared in August of this year.

The last post that was made regarding these pupae was just a few days after we moved to Ithaca, New York where we recorded the final mass data after all of the larvae had pupated as reported by our mother. 

Although all but three of the larvae had already pupated while we were still in Albany, this is the first time that we can officially showcase all of the pupae together, which is shown below. 

Interestingly, all three of the last pupae were light morphs, whereas 100% of the other pupae were dark with the exception of a few that we allowed to pupate outside on trees instead of in empty tubs. While nobody was home to see what was taking place in the last days of these three individuals' larval stages, it is assumed that they spent almost or all of their time as prepupae in the container that they were being kept in that was stuffed with willow (Salix) cuttings, suggesting that some factor related to presence of live plant material may influence color.  

While the overwintering naked pupae of most other species we have reared usually experience a fair number of losses, all of these rutulus pupae are still alive, which is both somewhat surprising and a relief, although there are still a few more months to go before they are to eclose. This high survival rate can probably be owed to a combination of excellent sanitation, both before and after pupation, and to the fact that this is local stock that follow very strict seasonality and so are well suited for going through this type of long diapause. The same cannot be said of the local anise swallowtails (Papilio zelicaon), which breed vigorously and haphazardly for as long as they possibly can, or the local pipevine swallowtails (Battus philenor hirsuta) that have a chaotic diapause pattern reminiscent of the tropics; both typically suffer significant losses during diapause. 

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Authors
Brian Liang

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