Butterflies in Winter
Danielle Bell, Communications Chair
Sifting through photos from warmer days, I reminisce of bright colorful summer scenes with butterflies flitting between flowers and bees busily collecting pollen. What happens to these colorful insects during the frigid months of winter? Do they migrate? Do they die? What do they do when the world becomes cold and gray?
Most of us know about the great Monarch migration to warmer areas each fall. They begin the long trek to Mexico or Southern California once the prairies are colored purple and gold by New England Asters and Stiff Goldenrods. However, they aren’t the only ones to migrate south. Although their route is the longest there are other species of Lepidoptera (butterflies and moths) that also head to warmer climates each fall. Red Admirals and Painted Ladies are two examples of species that spend the summer months throughout the United States but migrate south to overwinter in the southern states.
Ever wonder why Mourning Cloaks are the first butterflies of the year seen flying around as early as March? In the fall they increase the glycerol and other anti-freeze agents in their blood and carefully select their overwintering location. This could be under the flaking bark of a Shagbark Hickory or in a rock crevice. Here they patiently wait for the first warm days of spring when daylight hours lengthen and the sap of the maples begin to flow.
Other species of Lepidoptera will tough out the winter months in a state of diapause. This is a state of dormancy where their metabolism slows and development stops. Silk moth pupae, like the pictured Polyphemus, weave their cocoon inside a leaf to protect them during the winter months. Inside the fibers of the cocoon a pupa is present, trapped in the transitional phase between larvae and adult. Once warmer temperatures return in spring, this large silk moth emerges ready to find a mate and create the next generation.
Some species in the Skipper family overwinter in our region as caterpillars. They prepare for diapause during the later instar phases. Once warmer temperatures and food sources (grass species) return they finish their larval phase and pupate into adults. Other species pass the winter in their egg stage. According to Butterflies and Moths of North America (BAMONA), Bog Coppers overwinter underwater as eggs.
So, if you think you can only see butterflies or moths in photos during the winter, think again. They may not be as bright and eye-catching as we find them in summer, but they are still there. You just need to know where to look!
Mourning Cloak in October preparing for diapause
Mourning Cloak in March emerging from diapause
