Learn.genetics.utah.edu what makes a firefly glow

Larvae use their glows as warning displays to communicate their distastefulness. As adults, many fireflies have flash patterns unique to their species and use them to identify other members of their species as well as to discriminate between members of the opposite sex. Several studies have shown that female fireflies choose mates depending upon specific male flash pattern characteristics.

Higher male flash rates, as well as increased flash intensity, have been shown to be more attractive to females in two different firefly species. The adult fireflies of some species are not luminous at all, however, and instead use pheromones to locate mates. The use of pheromones as sexual signals appears to be the ancestral condition in fireflies with the use of luminous sexual signals as being a more recent development. There are species that employ both pheromonal and luminous components in their mating systems.

These species appear to be evolutionarily intermediate between the pheromone-only fireflies and flash-only fireflies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Fireflies are filled with a nasty-tasting chemical called lucibufagens, and after a predator gets a mouthful, it quickly learns to associate the firefly's glow with this bad taste!

So not only does the flashing help attract a mate, it also warns predators to stay away. One species of firefly that can't make its own lucibufagens acquires it by eating others that can. To lure victims, these fireflies mimic the flashing pattern of another species. When the unsuspecting male approaches to find a mate, he instead becomes a tasty treat to the tricky firefly.

This video from Brigham Young University offers a quick glimpse of these remarkable insects that make their own light. Goodsell, D. Female fireflies hang out on a tree branch or in the grass while the males fly around showing off their best flashes. When a female recognizes the flash from a male of the same species, she will answer with her best flash. Another reason that fireflies glow is to avoid predators.

Fireflies are filled with a nasty-tasting chemical called lucibufagens, and after a predator gets a mouthful, it quickly learns to associate the firefly's glow with this bad taste! So not only does the flashing help attract a mate, it also warns predators to stay away. One species of firefly that can't make its own lucibufagens acquires it by eating others that can. To lure victims, these fireflies mimic the flashing pattern of another species.