Firefly Flashing Means Both “Let’s Do It” And “Don’t Eat Me”

Remember that hot Science Times article from this summer explicating just how fireflies’ light flashes are a call-and-response mating system? “In at least some species,” wrote bug smut peddler Carl Zimmer, of stuff he learned from Tufts University evolutionary ecologist Dr. Sara Lewis. “Females may use flashes to pick out males with the biggest gifts.” (“Nuptial gifts” being coiled packages of protein males fireflies inject into female fireflies along with their sperm.) Well, turns out that the phosphorescent flashes serve another, less sexy purpose, too.

According to an article at the Discovery Channel website, fireflies flash as a warning to bats, and maybe other potential predators, not to eat them.

“Fireflies are often toxic to bats,” writes Discovery’s Jennifer Viegas, “which see the nighttime flashing and steer clear of the insects.” She cites a recent study by Paul Moosman, Jr., an assistant professor of biology at the Virginia Military Institute, who says, “I believe it is quite possible that bats would attempt to eat fireflies, especially if the firefly was not flashing.” (Surprising, because everyone thinks of bats as totally blind. Not totally: Mooseman explained that bats’ famed echolocation is good for navigating and foraging system, but it “is an imperfect mechanism for identifying prey.”)

The problem with the warning flashes (and this goes back to that first Times story), is that there are certain other predators-another, cannibalistic species of fireflies in fact, called Photuris-that actually do like to eat fireflies. These sick fucks watch for the flashes of their amorous brothers and sisters, only to swoop in and devour them in the act. “They pounce, they bite, they suck blood-all the gory stuff,” Dr. Lewis said. That’s some Friday the 13th shit right there.