Reading. Firefly

It’s a quiet, warm summer evening with no human in sight for miles in the woods. As the sun sets, tiny flashes of light start to flicker throughout the trees. At first there’s just a few, but soon hundreds of blinking lights are floating in the forest. Fireflies have come out for the evening.

Also known as lightning bugs, fireflies are beetles. Most fireflies are winged. That’s different from other light-producing insects of the same family, called glowworms. (Animals that produce light are called luminescent.)

There are about 2,000 firefly species. These insects often live in humid regions of Asia and the Americas, where they mostly feast on plant pollen and nectar. Firefly larvae—recently hatched worm-like fireflies that haven’t fully developed yet (including their wings)—feed on worms, snails, and insects.

Fireflies mostly use their light to “talk” to other fireflies and find a mate. They have special organs under their abdomens that take in oxygen. Inside special cells, they combine the oxygen with a substance called luciferin to make light with almost no heat. They use this light, called bioluminescence, to light up the ends of their abdomen.

Each firefly species has its own unique flashing pattern. When a male firefly wants to communicate with a female firefly, he flies near the ground while he flashes his light every six seconds. Once he’s near the ground, a female can more easily tell if he’s from the same species as she is. (Most female fireflies can’t fly.) She answers his flashes by turning on her lights. Then the male finds her.

Predators, such as birds or toads, get a different message from these lights. Although they can easily spot fireflies by their glow, they rarely eat them. That’s because fireflies release drops of toxic, foul-tasting blood. Their flashing is a warning light to predators to stay away.