Photinus Firefly (probably)

Yesterday I talked about the Dogbane Leaf Beetle as one of my favorite beetles, but there are other contenders. Here's a firefly, probably in the Photinus genus. And in my area, the most common of these is the Common Eastern Firefly. And yes, despite their common names of "firefly" and "lightning bug", these insects are neither flies nor true bugs but are a type of beetle.

Identifying these guys in daylight (at least down to the species) is difficult. My book Fireflies, Glow-worms, and Lightning Bugs (by Lynn Frierson Faust) relies a lot on seeing their flash pattern and color. If this is a Common Eastern Firefly, at night I should see a flash that lasts long enough to look like a Nike swoosh or the letter J, and this should repeat every 6 seconds with a mostly yellow color. Other species may have different colors (green or orange aren't unusual) and a different flash pattern.

But seeing one in daylight makes the ID less reliable. My book states "Frankly, all Photinus can look very similar in the field, with small differences in size, pronotal markings, coloration on abdominal segments, and wing-cover margins."

Of course, much of what makes these guys special is their bioluminescence, a trait we don't see a lot of. For most fireflies, bioluminescence is a dating tool, where males signal availability and females signal their receptiveness. But bioluminescence may also deter predators, since fireflies are somewhat poisonous/distasteful, and their flashes tell predators that they're not your typical tasty insect.

Firefly at Duke Farms