When you think of nature in winter, you might think of snow, bare trees, and cold temperatures. If you’ve ever visited the Cape Cod Canal during the winter, you might think of eiders. Few people, however, would say “insects” as their first thought. 

While many insects are dormant through the winter, there are some who like to buck the trend. The winter firefly (Ellychnia corrusca) is one of these. They belong to the family Lampyridae, which includes fireflies and lightening bugs. But don’t let the common names fool you. These are soft-bodied beetles, not flies or bugs.

The winter firefly certainly likes to march to its own beat. For starters, it’s actually a complex of closely related species, even though it is often described with a single name. It is also unique in the time of year it’s active. As their name suggests, they’re active in the colder months when other fireflies are absent. Winter fireflies have a lifespan of two years and overwinter as adults, allowing them to become active as early as February if temperatures are mild. The photos included here were taken on February 18th a couple years ago.

Finally, although it’s a firefly, it looses its ability to glow as an adult. All other life stages, including the eggs, larvae, and pupae, have the ability to bioluminesce (this is thought to serve as a warning to potential predators of their distastefulness). But after only a few hours as an adult, winter fireflies lose this ability completely. As a diurnal species, the ability to glow is likely less important than it is for their nocturnal cousins. Instead, it is believed that winter fireflies locate a mate using pheromones. 

So, as we move into February, especially as we get a warm spell here or there, keep an eye out for these unique winter insects. Their black and pink bodies are quite easy to spot against a snowy background. But even without snow, check the sunny side of trees. Winter fireflies tuck into cracks in tree bark to keep out of the elements and will emerge to bask in the sun and warm up on mild days.