the lunas

August 27, 2009

in Insects,Natural history

We left off with dozens of silkmoth caterpillars snug in their cocoons. For the most part, I expected these to overwinter. I'm at 42 degrees N latitude, and, for instance, the Luna eggs were laid on on 30 May, the first started hatching on 16 June (16 days), the first cocoon was spun on 13 July (27 days).

We had all the Luna cocoons in a big cat litter bucket. The screen top also covered a bucket of Cecropia larva. Three weeks after the first cocoon was spun, I looked in the bucket and was surprised to see an adult Luna. This was on 4 August (21 days after the first cocoon was spun, although I don't know if it was the same individual).

This first adult was a male, which we let go at my work, the original intention. The next day a pair eclosed.


Two fresh adult Lunas, chubby egg-filled female on top.

We originally put the female in a wire cage overnight, to see if the female would call in a wild male. During the night (the time varies among species) female silkmoths exude pheromones from a gland that protrudes from the tip of the abdomen. Males detect these pheromones with their feathery antennae and may come to mate from miles around. But, no luck that first evening.


The next night we put the pair in another bucket lined with paper towels. When I checked them at 2:30 AM (I had read Lunas call between 1 and 3 AM), the pair was mating. They remained coupled together all day the following day, which was very rainy. We'd hoped she'd lay a few eggs on the paper toweling and we'd be able to let them go that night, along with several others that had eclosed, but it didn't look as if the rain would let up.


We watched this male shove his way out of his cocoon. Freshly emerged, his wings looked like dried apple chips.

It stopped raining just before we went to bed, and when we checked on the moths before turning in for the night we found that the pair had uncoupled and the female was laying eggs — rapid fire, as fast as a sewing machine! Having no desire to raise 200 more caterpillars, we grabbed the buckets with all the moths and rushed to go release them.


Fresh Luna eggs.

The females aren't very inclined to fly, so we let them clamber up the trunks of a couple walnut trees. We set the males down near them. A couple of them flew off, a few seem interested in hanging around the females.


I was expecting the eggs to hatch in about two weeks, same as the first time. But after only 8 days I came home from work to find a couple dozen minute Luna caterpillars wandering all over. Round two of foster parenting has begun!


Diane August 27, 2009 at 12:12 pm

Amazing to see… thank you for posting this!

Wild Flora October 9, 2009 at 9:20 am

I really enjoyed these two posts. Thanks so much.

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