First Hyalophora cecropia Pairings of the Year

Two of the three captive Hyalophora cecropia females we set outside paired with wild males last night. These are the first pairings of this year.

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On the third night since we started setting captive females outside to call in wild males, we finally got pairings with two of the three females. The two females were the larger of the three, one of which eclosed three days ago that failed to call in a male the past two nights, and the other of which that just eclosed yesterday. Both also happened to be in the wire cage with larger holes (1 square inch) that we switched to last night since we suspected the cage with smaller holes (1/2 square inch) that we used the past two nights was physically preventing males from copulating with the female. The female that failed to pair was the smallest of the three and was in the cage with smaller holes. This suggests that our suspicion was perhaps correct, though sample size is small and it could be a coincidence. Either way, though, we'd rather play it safe and use the one with larger holes from now on, even if there is a small risk smaller individuals could escape.

The wild males in the pairings were still paired with the females long after the sun rose and remained coupled until dawn. Like we observed last year with the wild males called in, they are extremely large compared to our captive males and even a bit larger than the females. Alas, growth in the wild must be much superior to captive, crowded, conditions even when reared in sleeves. In addition, the males have darker, more contrasting colors, with a darker gray ground color, crisper white and red margins, and darker red body. This differs from our captive individuals (both male and female), which tend to have a lighter grey ground color that is infused with more white and yellow scales and have lighter red bodies. We noticed the same thing last year and weren't sure if it were genetic or environmental. We are starting to suspect it is more environmental at this point, since the males from last year and this year have been consistently this darker phenotype. Perhaps the temperature and humidity that the cocoons diapaused or developed under affected the coloration? Not sure if we would ever know for sure but it's an interesting to note.

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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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