Firefly Facts
Size 0.47-0.78 in (12-20 mm) (female); 0.19-0.78 in (5-20 mm) (male)
Speed Unknown
Weight 0.0007 oz (0.2 g)
Lifespan About 2 months
Food Little insects/snails, pollen, nectar
Predators Frogs, spiders, birds
Habitat Worldwide (except Antarctic region)
Order Beetles
Family Fireflies
Scientific name Lampyridae
Characteristics Glows at night
A Little Worm? Me? Really?

Fireflies are also called lightning bugs or glow worms. However, fireflies are no worms, they are classified as bugs.

Why Do Fireflies Glow?

Most Fireflies are nocturnal animals, and of course they have to attract attention somehow when looking for a mating partner. While the ladies are climbing up plants or trees (because they cannot fly), the male fireflies hover about at a height of approximately 3 ft (1 m) and look out for them. The females start their “glow concert” and act just like flight controllers trying to wave the male fireflies nearer. Both females and males glow, yet the ladies shine much brighter.

Firefly Firefly - Photo: IanRedding/Shutterstock

Not Only at Night

There also exist diurnal fireflies. They only glow faintly or not at all, for example in shady areas. During daytime nobody would perceive their light!

At What Time Do Fireflies Glow?

Mostly during dry summer nights between 10 p.m. and 12 a.m. They hide at secure places when it’s raining.

1,001 Ways to Glow

Fireflies shine in various ways and differ in
- the color of their light
- how long they are glowing
- how often they light up
- the intervals between lighting up
- at what time at night they glow

Firefly Firefly - Photo: Brandon Alms/Shutterstock

Bioluminescence ... Bio What? The Science Behind the Glow Effect

The term bioluminescence indicates the capability of creatures to generate light. It is based on the Latin verb “luminare”, which means “light up, illuminate”. Fireflies use chemical processes to generate energy in the form of light. The so-called luciferin (a natural substance for the generation of light) causes a chemical reaction together with an enzyme, a kind of energy component, and oxygen. By the way: The light can only be perceived at the lower back parts of the shell, because these are translucent.

Brrrr – Your Glow is Rather Cold!

Probably you have already imagined catching a fireflies with your hand and carrying it around as a warming light. Just like a miniature light bulb. Haven’t you? You would be surprised, because the light produced by the little bugs is rather cold. It does not contain any infrared or ultra-violet light.

Efficiency Record: Fireflies are Super Light Bulbs

A normal (old) light bulb generates 97 % heat and only 3 % light. Fireflies can transform 95 % of energy into light. There is no light source developed by humans for domestic use that can compete with the little bugs.

The Larvae Are Also Glowing

Yet, they don’t do this to attract mating partners as they are not mature enough for this. They signal their enemies: “I taste really bad” or “I am poisonous”. You would not appreciate glowing food on your plate either, wouldn’t you?

No More Glowing – Fireflies and Their Predators

Lizards, birds, frogs, and spiders love to feed on fireflies.

Firefly Firefly - Photo: Anita Patterson Peppers/Shutterstock


Adult fireflies have only a few weeks to live. They hardly eat anything during this time, because they are busy finding a mating partner. After a few weeks, little larvae hatch from their eggs. They remain in this stadium for up to three years and have a mighty appetite for little snails and insects. As soon as they have grown enough, they develop further and look for a partner to lay some eggs.

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