A couple of months ago, a fellow MOSI staff member brought us a gorgeous moth she’d found in her yard. It turned out to be a female Imperial Moth (Eacles imperialis), and to our great delight, she eventually laid us some fertilized eggs. Within a few weeks, they had hatched, providing us with about 50 tiny Imperial moth larvae to raise. In their first instar, they were small and orange with fascinating branched setae all over their bodies.
Fast-forward about six weeks… after gorging themselves on Longleaf Pine (Pinus palustris) day after day, our tiny little caterpillars were now enormous monsters, 4- 5 inches in length and bigger around than a thumb. Their pine-scented frass filled the bottom of their tanks (they are possibly the most pleasant-smelling caterpillars we’ve raised in awhile!) as they stripped the needles from large branches in no time at all.
In the wild, Imperial Moth caterpillars climb down from trees and pupate in the leaf litter, so here in the lab we provide a box of leaf litter for them. When the larva are ready to make the transition to cocoon, they stop eating and begin to expel all the extra moisture from their bodies. They shrink down to perhaps a quarter of their size as full-grown caterpillars, growing stiff and nearly motionless. Finally, they shed their skin one last time and become pupae, a bright reddish color at first changing to a darker color as the pupa hardens.
Now that they’ve all gone to cocoon, it will likely be many months before we see them again. Even in Florida, Imperial Moths raise only one brood a year. As members of the silkmoth family, adult moths have no mouth parts and do not eat. When they emerge from cocoon next summer, they will have just a few days to mate and then lay eggs (the females, at least). We will keep the cocoons safely in the lab until then, so when they do emerge, with any luck we’ll be able to gather more eggs and raise another set of these amazing creatures.
For information on the adult Imperial Moths, including pictures, click here to read a previous post.
Thank you for this - so concise and informative! I had an Imperial Moth lay many eggs inside my car (long/sweet story). I gathered them and quite a few (30-40) hatched. Some did not live long, but about 25 are now growing fast and strong on a diet of scrub pine (fortunately I have a plentiful supply!). They started hatching on July 30 - and it is now August 22 - so I'm guessing they have about 3 more weeks of happily gorging themselves (so fascinating to watch!) before they pupate. Which brings me to my question: you mention providing a bed of leaves for them at this stage - do you put the leaves in the bottom of the container in which they have been feeding (in my case, it's a large "file-box" sized plastic container, in which I place fresh pine boughs and from which I clean out their droppings every other day (sure wish the poop of the many other critters we've raised over the years smelled so sweet!!). Would it be best to set up a separate box at the appropriate time and move the caterpillars there after they have begun the signs mentioned above that they are moving toward pupating? And, how do you keep the pupae? Away from moisture? Closed up? In an open box? Thanks for any tips - I am so grateful for the experience of this journey of life!
ReplyDeleteWe used leaves and soil but you can use pine straw that you gather from under your pine trees. We placed our leaves and soil in a plastic dishpan and put it inside the rearing container. Most of the caterpillars gravitated there on their own. The few that did not and began to pupate on the floor of the rearing container, we helpfully moved to the dishpan. Once all of the moths had pupated we moved the dishpan of soil and pupa into a netting container. You can usually find them as student laundry hampers or collapsible laundry hampers. When the soil looked too dry, we would mist water onto the soil in the dishpan (about twice a month-ish) so they would not dry out too much. The netting container is helpful because your moths can emerge inside this container and climb the sides to dry their wings. We also placed a branch in the dishpan that leaned over to the mesh wall of the container. This way, emerging moths did not have to struggle to get out of the dishpan to dry their wings. It's worked out nicely and the most recent batch are currently emerging and mating and laying eggs.
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My son found an Imperial Moth Caterpillar in it's last stage before it will pupate. We're wondering if we can keep it inside in a container over the winter and see it emerge in the spring. It is August and we live in Wisconsin -- about the furthest North these creatures apparently venture. Any advice would be appreciated!
ReplyDeleteHere's what has worked for us:
DeleteWe use leaves and soil that we gather from under nearby trees. We placed our leaves and soil in a plastic dishpan and put it inside the rearing container . Most of the caterpillars we had gravitated there on their own. The few that did not and began to pupate on the floor of the rearing container, we helpfully moved to the dishpan. Once all of the moths had pupated we moved the dishpan of soil and pupa into a netting container. You can usually find them as student laundry hampers or collapsible laundry hampers. When the soil looked too dry, we would mist water onto the soil in the dishpan (about twice a month-ish) so they would not dry out too much. The netting container is helpful because your moths can emerge inside this container and climb the sides to dry their wings. We also placed a branch in the dishpan that leaned over to the mesh wall of the container. This way, emerging moths did not have to struggle to get out of the dishpan to dry their wings. It's worked out nicely and the most recent batch are currently emerging and mating and laying eggs.
I found a pupae last night laying on the ground not buried with a shell of the caterpillar laying next to it we have it now in the garage and would like to keep it till it hatches....any advice would be most helpful.we live in Illinois but garage is heated.
ReplyDeleteHere's what has worked for us:
DeleteWe use leaves and soil that we gather from under nearby trees. We placed our leaves and soil in a plastic dishpan and put it inside the rearing container . Most of the caterpillars we had gravitated there on their own. The few that did not and began to pupate on the floor of the rearing container, we helpfully moved to the dishpan. Once all of the moths had pupated we moved the dishpan of soil and pupa into a netting container. You can usually find them as student laundry hampers or collapsible laundry hampers. When the soil looked too dry, we would mist water onto the soil in the dishpan (about twice a month-ish) so they would not dry out too much. The netting container is helpful because your moths can emerge inside this container and climb the sides to dry their wings. We also placed a branch in the dishpan that leaned over to the mesh wall of the container. This way, emerging moths did not have to struggle to get out of the dishpan to dry their wings. It's worked out nicely and the most recent batch are currently emerging and mating and laying eggs.
I have a question, do you get the leaf litter from just any old pile of available leaves? I have a Imperial Moth Caterpillar now and will soon need to provide the leaf litter container. Thank you
ReplyDeleteI usually collect leaves and soil from the base of their host plant.
ReplyDeleteThanks for the info I am so glad you too such great care of these lave! I was looking everywhere for where these larvae could feed. Because i had a female Imperial Moth lay 50 eggs in my room She died I got them up and was wondering where to put them outside. Thank you so much for the info! :)
ReplyDeleteI found a female moth, who was barely moving, so I put her in a small plastic critter container overnight to protect her from getting eaten. Well she laid eggs in there! What is the best thing to do now?
ReplyDeleteIt's time to find some longleaf pine if the moth was an Imperial. If you don't want to raise the caterpillars, just wait until the eggs hatch and take them to their host plant and drop them off to do their thing.
DeleteDoes temperature come into play at all when the caterpillar becomes pupae? Or even before that? I have about a 4inch imperial moth caterpillar I found and am new to this! Any other tips you can think of that weren't previously mentioned would be greatly appreciated!
ReplyDelete