There are so many interesting tidbits about mourning cloak butterflies that it’s hard to know where to start.
Nymphalis antiopa are stunning and distinctive, and they’re one of the longest-lived butterflies. They’re often the first to emerge in the spring and the last to be seen in the fall. Even so, and considering they’re found in nearly every U.S. state, March 2024 was the first time I’ve seen one at Mount Pisgah.
During the winter, they hibernate (in an aptly named hibernaculum) and in the summer, they aestivate, or take another dormancy break while it’s hot. The double down-times are unusual for any animal. Scientists think the summer break happens in order to conserve energy and reduce wear and tear. The adult butterflies have to make it though the winter, after all, in order to mate in the spring and produce the next generation.
Mourning cloaks are able to fly on cool but sunny winter days because their bodies have furry, warmth-retaining bristles. They can exercise their flight muscles to bring their core temperature up about five degrees, and the deep brown upper wings act as solar panels. This one stayed still, sunning itself for quite a long time as I snapped away dozens of photos.
The underside of the wings provides excellent camouflage on tree trunks or in leaf litter. But they’ve got more tricks available in case a bird or other predator recognizes them as a snack. First, get this, they can emit a clicking sound as they snap open their wings, which then flash their distracting, colorful blue eye spots. If all else fails, they have a Plan C (or D?)—these butterflies will fold up and drop to the ground, where they blend with the leaf litter, and play dead!
Stay curious!
See more of Karen’s work here.
Sources:
Video of mourning cloaks playing dead: https://www.youtube.com/watch?v=mtij1k-FtfU Accessed 3/18/24.
iNaturalist information page: https://www.inaturalist.org/guide_taxa/365828. Accessed 3/18/24.
