How long a caterpillar lives before spinning a cocoon varies depending on the species. The wooly bear caterpillar spends up to 14 years as a caterpillar. Most caterpillars only live for a few weeks. Tent caterpillars live for six to eight weeks and monarch caterpillars are fully grown in about two weeks. Their eggs hatch about four days after being laid and they start on their binge eating by eating their own eggshell first. They then start on the leaf they were laid on. They outgrow and shed their skins five times before they finally become a chrysalis, each time becoming bigger and more vibrant with longer tentacles.
The Hickory Tussock Moth (lophocampa caryae), the same caterpillar on the apple in my previous post, is not the only caterpillar we have found at the cottage. I thought we found a Woolly Bear Caterpillar, but it only had black one end and typically they have black both ends. The woolly bear caterpillar is an Isabella tiger moth and it became famous in 1948 when Dr. Curran collected and studied them in Bear Mountain State Park and predicted the coming winter weather by looking at the average number of reddish-brown segments. He spent the next eight years trying to prove it scientifically. Folklore says winter will be mild if the brown stripe is thick and severe if the brown stripe is thin, but actually the brown band increases with the age of the caterpillar.
Having dug a little deeper, I think our guy was a Garden Tiger Moth or Great Tiger Moth (Arctia caja). These guys spend the winter on the ground in protected places like the Woolly Bear caterpillars, but they only do that for one winter.
Another caterpillar that we found was a small skinny one. I haven’t been able to identify it, so I can’t tell you what it is.
Perhaps the most impressive caterpillar find was an Eastern tent caterpillars nest. The lappet moth lays an egg mass of 200-300 eggs in late spring or early summer and within three weeks there are fully formed caterpillars within the eggs. They don’t chew their way out of the eggs until the following spring, just in time to feast on the buds of the host tree. The newly hatched caterpillars construct the silk tent soon after emerging and you can see the tent expanding each day as they increase in size.
We were concerned about our tree when we found the tent caterpillars had made their home in it. We were advised to set fire to it at night, when they would all have finished feeding and be back in their nest. I have since read that they don’t normally kill trees outright. Damaged Aspen trees sometimes recover and regrow leaves within several weeks, so perhaps we were too hasty in removing the nest? However, it does weaken the tree and make it more vulnerable to disease, so it probably was the best course of action to take. There is a fine line between letting nature do its thing and providing a helping hand to give us the environment we want. Sure we love caterpillars, but not if they eat our trees! I guess a more natural approach might have been to rip the webs apart and let the birds take over. Maybe next time…although I really hope there isn’t a next time – as cool as it is to see the structure these caterpillars build, I don’t like being the one serving them a death sentence!