Taking Pupae Out of Overwintering

We have taken pupae of Papilio glaucus, Papilio rutulus, and Papilio zelicaon, and cocoons of Hyalophora cecropia and Callosamia promethea out of the refrigerator to break diapause as the growing season begins.

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Earlier in January of this year, we put all of our pupae from last summer's rearings in the refrigerator at 5° C  for them to overwinter. Now that the weather is becoming consistently warm (20+ °C) and the leaves beginning, we decided to some of the species out to break diapause.

​The three swallowtail species, Papilio glaucus, Papilio rutulus, and Papilio zelicaon, we initially took out on 5/1 to let them acclimate to room temperature. All of the glaucus and rutulus pupae appeared to be alive and most of the zelicaon appeared to be alive. Then on 5/3, we took them to the climate chamber (27 °C, 75% humidity) to aid in breaking diapausing. Pupae from each species were hung upside down in three seperate mesh pop up cages for eclosion. We expect them to eclose relatively quickly within the next few weeks and intend on hand-pairing them to obtain eggs.

The other two species taken out on 5/1 were cocoons of Hyalophora cecropia and Callosamia promethea. We assume most of the cecropia cocoons are alive just based on how they "feel" when rattled, though for sure a few must be dead based on a foul smell coming off of them; all four promethea cocoons are definitely alive. We placed the cocoons at the bottom of a mesh pop up cage on moist paper towel at room temperature. We expect these to eclose near the end of this month (in three to four weeks), when we assume the flight of the wild population of each species would normally begin based on reported sightings in New York and when we encountered wild individuals last year (wild males called in by captive females late May for cecropia and a wild cocoon that eclosed early May for promethea). We intend to set out females of these two species outside to call in wild males to obtain eggs for this year's generation.

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Alan Liang​
​Alan Liang is a student at Cornell University in Ithaca, New York pursuing an undergraduate degree in entomology. He is co-owner and a main contributor of the Liang Insects blog and photographs.

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