Much like humans, female fireflies find their mates by judging which male has the biggest ‘package’. But it’s probably not the package you’re thinking of. Female fireflies are actually much more interested in a “nuptial gift”, which is what a male firefly injects into the female along with his sperm. A nuptial gift is a small sac filled with tons of protein and nutrients which the female is able to use in order to sustain her eggs. In other words, the bigger the package a male has, the more nutrients her eggs can use to survive. Female fireflies will assess which male is the best mate by observing their possible partner’s flashing signals.
Originally, a firefly’s light was thought to be used as a warning signal for predators, since some fireflies are filled with toxic or poisonous chemicals that could damage the hunter. However, it was found that only lampyrid, or young, larvae used the light for this purpose. Adult fireflies actually use the light to attract mates. The light is created by the chemical bioluminescence, which is formed by a chemical reaction in the firefly’s abdomen area, where the light-emitting organs reside. Fireflies can use the light in a variety of ways to attract a mate, such as blinking, flashing, or steady pulsing. However, having a nightlight doesn’t mean these fireflies are completely safe. Female Photuris fireflies are known to imitate the mating flashes of other fireflies in order to lure them closer. Unsuspecting male flies are then quickly devoured before they have a chance to realize what’s wrong. I bet a lot of us could compare this horrific method of sabotage with our ex-girlfriends.