Ever wondered what butterflies do during the winter? A few migrate each year (like the Monarch), but most overwinter in our area, either as adults or larvae. The Viceroy, Limenitis archippus, has a nifty strategy to survive. When these caterpillars molt for the first time they begin monitoring daylight. They can sense when the days are getting shorter, and each caterpillar makes the decision whether to enter diapause (dormancy) or to continue developing. With the approach of fall, most will enter diapause and build hibernaculum; small cocoon-like structures that protect them during the winter.
I raised several Viceroys last summer and knew where I might find these dormant caterpillars.
 |
| This may just look like a dead leaf, but it has a little caterpillar inside! Well, probably, I didn't actually rip it open to check. |
Yesterday I ventured out and found a half-dozen or so hibernaculum on a small willow near our farm. The key to finding them is to look for rolled-up, trumpet shaped dead leaves that are tied to the twig of a willow tree.
When the weather warms up in the spring, these caterpillars emerge ravenous, and do little but eat until they pupate and finally emerge as a butterfly.
The Viceroy caterpillar
The chrysalis
And the butterfly (Photo by Andrew)
The adult Viceroy is thought to be a Mullerian mimic of the Monarch. While not tasty itself, it mimics the pattern of the more poisonous Monarch, so as to not be eaten by birds and other predators.
If you want to learn more about raising butterflies, you should check out this very helpful site. I successfully raised several species last summer and hope to try several new ones this year.
Joseph
