It occurred to me a week or two ago that every insect that goes through simple metamorphosis, also known as “hemimetabolism,” leaves behind a shed exoskeleton every time they grow into a new stage. For some true bugs, that’s five or six times. Grasshoppers also molt five or six times. I wondered: Why have I not seen more of these castings lying around? Shouldn’t they be littering the ground?
Well, maybe it’s a case of not looking for them, because the past couple of times I’ve been out, I’ve seen quite a few. They are fascinating to look at, and they don’t fly away on close examination. On the grasshopper exoskeleton above, you can even see the mouthparts and the spines on the legs.
One reason it’s easier to see these now is that there are more spider webs and debris on leaves this time of year, and the castings sometimes get caught in them. There was a huge population of boxelder bugs this year, and yesterday I found six or eight final molts like the one above, which I’m nearly certain is its last exuvia (that’s a fancy name for the shed exoskeletons–“ecdysis” is the fancy name for the process). It would be really cool to see the shedding in progress. Insects are especially vulnerable just after a molt, but that also means they are still for a while as they fill out their new body.
When cicadas have periodical surges, people see their castings littering the ground. This one was perched, solo, on the end of a cut log.
Spiders also shed their exoskeletons as they grow. Again: Why don’t we see more of these? Or are we simply not paying attention? On my wanted list: To see a praying mantis and / or katydid casting … also, to see any one of these in progress.
Cheers!
Ticklehead 