What happens to butterflies and moths during winter in New York?
They may seem as delicate as gossamer, but moths and butterflies routinely survive the cold, harsh weather of New York winters. How do they do it? After all, they are small, without any insulating fur or feathers, and cannot generate their own body heat as mammals and birds do.
Some adult invertebrates like these overwinter in protected shelters. One way they withstand freezing temperatures is by secreting chemicals that act as antifreeze to prevent the formation of ice crystals in their bodies. The comma and mourning cloak butterflies are two such insects. (Visit The Butterfly Conservatory to see hundreds of live, tropical butterflies from around the world.)
On milder winter days, with temperatures in the 40s°, these butterflies may even emerge to bask, their dark scales absorbing the heat of the sun.
Winter moths such as straight-toothed sallow, Morrison’s sallow, and Grote’s pinion may also be seen on mild, humid winter nights, insulated by dense hairs on their bodies.
Some adult invertebrates simply die when the cold weather arrives, leaving their offspring to survive in a protected dormant stage as eggs, larvae, or pupae. Woolly bears (caterpillars of the Isabella tiger moth) find protection under thick layers of leaf litter.
Below is an Isabella tiger moth as an adult.
And polyphemus moth pupae are sheltered in their cocoons during the winter.
Here's a polyphemus moth in warmer weather, as an adult.
Photographed any winter moths or butterflies, or any other invertebrates, in New York City? Share them at New York is Wild!, the Museum's project at iNaturalist.org, where anyone can upload images and learn more about the wildlife of the City.
This post was adapted from this downloadable guidebook, written by Elizabeth A. Johnson.