Collecting Hyalophora cecropia Cocoons

Because we will be moving to Ithaca, New York tonight, we had no choice but to collect all the cecropia moth (Hyalophora cecropia) cocoons despite that not all larvae have spun.

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We never thought a cecropia brood started all the way back in April would still not be finished now in mid August. We normally would have collected all the cocoons once all larvae had finished spinning, but since we will be moving tonight, we had to collect all the finished ones and resleeve up the remaining few larvae with as many leaves as possible. 

The cocoons this year are far smaller than the ones last year, despite having received nearly identical treatment (indoors on apple first three instars, and sleeved outside in the last two). The only difference was that some of the larvae this year were sleeved since birth. The larvae this year also grew much, much slower than last year's which all finished spinning at the beginning of August and began in June. We can't really understand why this year's rearing was so poor. We started off with hundreds this year and nearly all died off overtime, mostly the ones that were sleeved since birth. Last year we started with three dozen and got about the same amount through and they were respectable in size, with females at 8 g and males at 6 g. This year, the cocoons are a measly 3-6 g. We didn't imagine cecropias could even get down to 3 g without opting for a supernumerary sixth. Maybe inbreeding reduced their size?

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​Authors
Alan Liang

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