Getting ready for winter

I know it’s been awhile since my last post. I’ve been having technical issues with wordpress and every time I go to write a post it messes up the other blog formatting. Anyway, hopefully it’s worked out and back to normal.

It’s that time of year in Colorado and other places with winter in the Northern hemisphere when the final leaves are falling off the trees and the first snows are starting. There is actually a distinct and fairly shocking change every year after the first hard freeze. All the insects you heard the night before (the crickets and the katydids and the like) have gone silent. Even if it warms back up to 50 degrees in a day or two (a likely event in Denver), the night symphony will not be back. The first freeze kills them.

But come Spring the insects you haven’t seen all winter will be back. Where did they go? How do they live all winter?

Insects have several strategies for surviving the winter. Some, like the crickets and the katydids, lay there eggs in the ground or in dead plant material in the fall. Although the first freeze kills the adults, their eggs are safe and sound. These eggs will hatch in the Spring, feed all summer, mate, lay eggs, and freeze. Another way to survive the winter is to be in dormant state, usually burred in the soil. This is what many moths do.

In the early fall, you can often find large fuzzy caterpillars walking around on the ground. They are looking for a good place to make a pupa. A pupa is what we call the stage of an insect’s life when it is transforming from a juvenile to an adult. From a caterpillar to a moth. A pupa is well protected against winter weather, especially with a little help from being burred in the ground or a pile of leaves.

This makes early fall a great time to look for caterpillars. And also a time when people start texting me pictures of caterpillars they’ve found. This year I had a good one waltz right up to the front door. Some dinner guests found him on their way in.



Despite looking like a fluffy animated monster, this is an American Dagger moth caterpillar. The black tuffs fall of easily thereby allowing the caterpillar to escape from predators. These guys eat a variety of trees including maples, box elders, horse chestnuts, alders, birches, hickory, walnut, ash, popular, oak, and willow. Because some of these are common trees to have in your yard, many people see these caterpillars.

Once the caterpillar has found a suitable place, it will become a pupa.



In the Spring an adult will emerge from the pupa. Even though the caterpillars are go exciting looking, the adults are rather drab.

downloadPhoto from

You can find lots of other pupa around if you look. Checking in the top soil or mulch or under pots will often yield pupa. They all look pretty similar but can be of all different sizes. Below is a pupa from the tobacco budworm featured in an earlier post.


If you are poking around outside, keep your eyes open for the winterized insects!


About keviclaire

I recently graduated from the Department of Environmental Science, Policy and Management at UC Berkeley. My research interests are focused on biological control and how to increase it's use in agriculture and home gardens. I am also an avid gardener and insect photographer. I'm using this blog as a place to share those interests!

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