by Violet Moshe, age 11
I’ve been raising giant silk moths for three years and am always happy to tell others about this adventure.
It all started one summer night, when my Mom and I attended a moth exploration led by Mary Gartshore, an ecological practitioner and an expert on moths. Mary was trapping moths at night in a forest in Norfolk County, Ontario. That night, while being eaten alive by mosquitoes, we learned about beautiful moths, native to the area, that we’d never heard of before, the challenges they face, and the work that Mary has been doing. We saw the setup for catching moths and lots of specimens that Mary brought with her. And then, out of the blue, Mary offered us cocoons to raise at home.
The following April, my grandfather drove to Mary’s house and picked up cocoons of Luna, Promethea, Polyphemus, and Cecropia moths, with detailed instructions on how to take care of them. Mary was so generous – we had lots for ourselves, for our friends, and for some TFN Juniors enthusiasts, too. We were excited about all of the different moths – we’d never heard of them until Mary spoke about them, and never seen them in nature, never mind up close.
In the end, though, my personal favourite type of moth turned out to be the Polyphemus moth. They were all gorgeous, but when we took care of them, all of the other moths would flap their wings like crazy and scare me, while Polyphemus moths tended to be more calm and gentle.
The process of raising moths is rigorous and requires a responsible child supervised by at least one dedicated adult. The cocoons have to stay outdoors and in the shade at all times – if they don’t, the moths might emerge earlier than they should (before the trees have leaves for the caterpillars to feed on). The cocoons need to be kept safe from predators, and misted with water daily. And all of this before the moths even emerge!
So it was vitally important for me to have a support team which included my handy grandfather who made several cages. The emergence cage, where the cocoons stay until they emerge, should be built with an outer shell of metal hardware cloth so that predatory mammals don’t chew their way in. Our friend in Scarborough lost his Luna moths most likely to bats because he didn’t keep them in the right cage (his Dad built an appropriate cage for next year). You also need a mating cage. The mating cage should also have a metal shell, however, the grid in this cage should be ¼-½ inch wide.
One of the things that really surprised me was that when the moths hatch, they look nothing like the mature moths we expect to see. As soon as they come out of the cocoon, their wings are crumpled up, because that’s how they fit inside the small cocoons. During the next half hour or so, the wings unfurl and the moth eventually becomes the huge beautiful creature that we long to see.
The first thing I’d try to do after jumping for joy at seeing the emerged moth is to identify whether it’s male or female. Usually you can tell if a moth is female or male by looking at its antennae. If the antennae are small, the moth is female. If the moth has wide bushy antennae, then it is a male. The males use their antennae to detect pheromones from a female, which may be kilometers away! And then they make their way to mate with her. The females’ antennae are much smaller and they use them to navigate to the exact types of trees that they lay their eggs on.
The entire life of a moth is about finding a mate and reproducing. They don’t eat, they don’t drink – they don’t even have mouths! The females release pheromones and wait for the male to come to them. The males sense the female, however far away she might be, and usually wait until evening to make their way to her, as most silk moths are nocturnal.
I remember how one morning we woke up to see the female Polyphemus that we had placed into a mating cage the night before, mating.
We were so happy! But then I noticed two Polyphemus wings on the ground close by. We tried to solve this murder mystery and figured that either two male moths were fighting over the female or some animal attacked the first one that came and then came the other one. I guess we’ll never know.
Once the moths finish mating, the male flies away and the female starts laying eggs shortly after. Following Mary’s directions, we placed the mated female in a big paper bag and left her to lay eggs inside. Afterwards we cut out the paper pieces with eggs attached to them. The eggs hatch in about two weeks and close to that time we used paperclips to hold pieces of paper with eggs onto the leaves of trees the caterpillars would eat.
Over the summer, the caterpillars grow roughly from the size of this dash — to the size of my thumb. They eat a ton, so every day you have to bring them fresh leaves. Remember “the very hungry caterpillar”? So true.
They are also, as Mary says, quite the escape artists, so they need to be kept in yet another cage, with sides made of tulle. Mary makes special tulle sleeves that she puts onto trees directly, but we didn’t have access to the trees and needed to bring branches of leaves into cages pretty much daily.
In order to prevent leaves from drying out, we put the branches into bottles of water. The first time we did this, we didn’t realize that the silly caterpillars might crawl into the water but that’s what happened. In a matter of just one day all of our caterpillars except for two had drowned. I was devastated. Afterwards, we kept branches in bottles, the opening of which we sealed with paper towels. It worked.
So we spent our summer caring for caterpillars: bringing them fresh leaves to eat, cleaning up their poop and marveling at their growth. We met lots of neighbours who helped us find trees to get branches from. My mom was weirdly amazed by the poop’s hexagonal symmetry. Picture a flower with six petals – that’s kind of what the poop looked like. If you stood in front of the cage when it was very quiet, you could hear the caterpillars biting the leaves and their droppings hitting the bottom of the cage.
By the end of the summer, the caterpillars make their silk cocoons wrapped in leaves. Interestingly, they also use their super strong silk thread to attach the leaf they are wrapped in, to the branch, so that the leaf with the cocoon inside can stay on the tree during winter. We kept our new cocoons outside all winter, too.
Watching the giant silk moths complete their life cycle has been magical. Every year, I’m amazed by how something can go through so many transformations. Some of my most thrilling memories have to do with this process. So many ups and downs. Excitement, followed by anxiety and stress, followed by more excitement.
My mom exchanged countless emails with Mary, especially when we were raising the first brood, because even with all of the instructions, we would still get so many questions. We wanted to make sure that the caterpillars and moths survive and thrive. I’m so grateful to Mary for the gift of this experience – learning about these magnificent creatures, and getting to know them on a deep level. Raising moths is a big responsibility and I hope more kids get a chance to experience it in all its beauty.