OLogy Cards > common eastern firefly

common eastern firefly

Have you ever caught a firefly on a warm summer night? Chances are it was a common eastern firefly (Photinus pyralis). Like most fireflies, it communicates with patterns of flashing light. These signals are used to find and attract mates, deceive other firefly species, and avoid predators. While many organisms make their own light, called
bioluminescence, fireflies are perhaps the most familiar.

Stats

Scientific Name: Photinus pyralis
Habitat: grassy areas in eastern North America
Diet: other insects, earthworms, and snails
Size: adult male is 0.4 inches (9-10mm) long
Lifespan: 5 to 30 days
Cool Fact: Males usually have much bigger eyes than females. Large eyes help them look for flashing responses from females.
Cool Fact: Some male fireflies provide "gifts" such as captured prey items to females.

Stumper

A firefly's light comes from a tiny organ on the underside of its body called a lantern. The lantern's light is produced by:

the insect's body heat

a chemical reaction

light absorbed during the day

Correct!

Inside the lantern, three substances interact to produce light: luciferin, luciferase, and oxygen. The chemical reaction forms a new molecule and releases energy in the form of light. The light produced by living things is called bioluminescence.

Stumper

Which firefly usually makes nighttime flights looking for a mate?

female

male

both

Correct!

Many wingless or tiny-winged females can't fly at all. The male firefly flashes a signal, and the female flashes her response. Unique flash patterns let males and females of the same species recognize each other in the dark.

Stumper

Fireflies don't use flash patterns just to attract mates. The blinking lights also warn predators that:

they're hot

they're poisonous

they taste bad

Correct!

While some bad-tasting insects warn attackers with bright colors, fireflies use their flash. Even firefly larvae (wormlike babies) glow.

Fact or Fiction

Fireflies aren't really flies.

Fact

Fiction

Fact

In fact, fireflies are beetles! These winged beetles have two pairs of wings. Flies have only one pair.

Fact or Fiction

Some female fireflies use light signals to catch and eat male fireflies.

Fact

Fiction

Fact

Some female fireflies might flash patterns from a different species to lure males from those species close enough to catch and eat.

Image credits: main image, Terry Priest CC BY-SA 2.0.

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