The Urban Pantheist

Sap bucket beetle, diurnal firefly, winter firefly Ellychnia corrusca

I am astonished that I somehow have not documented this species from the yard until today. I just searched my archives to make sure, and it appears that it was 365 urban species #77 but has not yet been part of the yard survey. It's not much of a coincidence that in the 365 project it was also found in March. These are some of the earliest insects found in New England, appearing even on relatively warm winter days. They overwinter as adults in the furrows of tree bark (and here in the cracks of my chicken run) and feed on flower nectar and tree sap. The common name sap bucket beetle comes from its frequent accidental presence in the buckets of maple trees tapped for sugaring.

These are beetles descended from bioluminescent ancestors, but have given up the key characteristic of their family. They fly by day so have no reason to light up at night. Mates are attracted to one another in the more usual insect way, by scent.

I've always had an affection for these soft-shelled, slow-flying beetles. At least once a year I'll grab one out of the air as it lazily flies by. It will crawl about on my hand for minute, trying to figure out what happened, and I'll look at the distinctive red markings on its underside and pronotum. There are about a dozen species of day-flying fireflies in North America, but this one is the largest, and I suspect the most common.

I didn't want to post a lot of natural history information with my 365 Urban Species "reminders," because it's there in the original post, but I guess a quick note wouldn't hurt:

Sap bucket beetles ARE fireflies, but they have lost the trait of bioluminescence through evolution, and mate in the daytime. This change in behavior has turned out to be an advantage over their lit-up cousins. Fireflies are rapidly disappearing from urban areas because light pollution makes it impossible for them to court and reproduce; if you find a firefly in the city, chances are good that it's actually a sap bucket beetle. Check the abdomen to be sure--a true firefly will have a light colored segment where the bioluminescence occurs. Often sap bucket beetles are called "diurnal fireflies," a common name which verges on being an oxymoron.

Of all the signs of spring, I like the insects the best. Sap Bucket Beetle.