April and the Pupae
Posted by Mary in 
Warmth finally came to the east coast last week. This past Saturday, I decided to take the moths out of refrigeration. I’m using an eclosure setup based on Pinebaskets‘ guidelines – a plastic tub lined with paper toweling – though with a solid lid and a misting bottle on hand to prevent the bugs from getting dehydrated should the temperature outside drop enough to trigger the furnace. Most of the time I’m keeping them in a room that’s unheated altogether. It’s still too early to expect emergences anytime soon, but they get peeked on several times a day!
The moths weren’t out for long before my curiosity got the better of me, and I decided to open the cocoons. Silkmoth cocoons are like little sleeping bags for the changing creature inside, so it’s generally safe to open a cocoon as long as the pupa inside remains unharmed. Doing this also allows one to determine the sex of the moths before they eclose. I went very slowly with a pair of tiny nail scissors tilted away from the pupae. All three were alive and safe inside and have been doing well since.
One of my Cecropia pupae with visible features identified.
Moth pupae are fascinating because you can see the features of the developing moth in the shape of the outside shell. The size of the antennae and outlines of the genitals reveal the sex, while the moth’s face, eyes, and wings are also visible on close examination. The wings look tiny compared to the whole body because they reach full size after the moth ecloses. My initial guess of one girl, two boys was off by a third: both of my cecropias and the luna are boys!
When exactly to expect eclosure is still uncertain. It can happen 1-3 weeks after the moths are removed from cold storage, which would mean late April to early May, but they could also take longer if spring temperatures continue to yo-yo. A mothing friend tells me females tend to come out before males, though I can’t test that myself this time. I do know that the moths will eclose in the morning. I’ll try my best to get pictures and/or video. The eclosure itself may be difficult to capture because it doesn’t take long, but even if I miss their first moments, there’ll be plenty of pictures of them as adults to share. Not so long now!
