- Catching fireflies is an important part of summer.
- Help us track where people are seeing fireflies in their backyard.
- Submit your sightings on the map and connect with others who spotted fireflies in your area.
Types of Fireflies
Scientifically, fireflies are classified under Lampyridae, a family of insects within the beetle order Coleoptera, or winged beetles. While most fireflies are characterized by their use of bioluminescence to attract mates and communicate with others in their species, not all insects within the firefly family produce light. Some communicate using pheromones, a sort of insect perfume.
There are thousands of firefly species spread across temperate and tropical zones all over the world. In New England alone, you might see twenty or thirty species. But all fireflies are classified under five main subfamilies.
If you live in North America, these are the fireflies you're probably most familiar with. Not all fireflies in this subfamily light up, but those that do are generally divided into three closely related species.
Photinus fireflies tend to be the most common of this group; about half an inch long, these produce yellow-green light.
Photuris fireflies are larger—almost an inch long—and produce a darker green light. They're very difficult to distinguish from Photinus from their light alone, even for other fireflies; female Photuris often mimic mating flashes from female Photinus fireflies to attract and eat Photinus males. Because of this, Photuris species are sometimes called “femme fatale” fireflies.
The following is an example of Photuris larvae. At this stage the larvae glow periodically throughout the night. They are found after dark crawling along the ground in the leaf litter looking for things to eat. The most common time to find them is after a big rain storm preceding a dry period. These particular larvae were found on the river bottom of the Devil's river in Texas during May 2015.
Pyractomena fireflies produce a yellow-amber flicker that looks a bit like a spark from a campfire.
This is the largest subfamily of fireflies, with member species scattered throughout Eurasia, Europe, East Asia, and Australia. The fireflies within this subfamily all produce light—and flash rather than emit a continuous glow. Here are a few genera of note within this group.
Peroptyx. Species within this group are mainly found in tropical Asia. Groups of fireflies will synchronize their flashes until thousands are all flashing to the same rhythm, producing a stunning display.
Luciola. These fireflies are sometimes known as “Japanese fireflies,” although they're also found in Asia and more rarely in southern Europe and Africa. In Japanese traditional culture, they are believed to represent the souls of the dead.
Luciola lusitanica Also known as the Portuguese firefly. Males of this species are the only ones that fly, females do not fly. Females are usually found on the ground or in vegetation, they are also bigger than the males. While males flash, females emit a long or continuous yet unsteady yellow glow from one light organ in it's abdomen. One advantage that non-flying female fireflies have is they are often able to lay more eggs than flying females. More energy that normally would be used for flying can be reserved and put towards laying more eggs. This enables a better chance of survival for more of their offspring.
This subfamily of fireflies includes two genera that live in North America and Eurasia. They're notable because scientists believe they are the most primitive species of fireflies in existence. One genus within this group displays very weak light, while the other does not light up at all.
Sometimes referred to by taxonomists as a “catch-all” subfamily classifying fireflies that don't quite fit into other groups, the species in this subfamily live generally in more temperate northern regions of the world, although a few species are tropical. The group contains both flashing and continuous-glow fireflies. Some larvae species within this group climb trees to feed on snails and bugs.
Lampyris is a genus of firefly within this subfamily found primarily in Britain, and they thrive in old-growth grasslands in soil with high concentrations of limestone and chalk. Only the males fly; the females are larviform, and only they glow. Females crawl onto blades of grass and low vegetation at dusk and emit a yellow-green continuous light to attract mates. Their vernacular name is “glow worm.”
Phausis reticulata also known as blue ghost fireflies. These tiny fireflies are common throughout the southeastern US and are known as the “blue ghost” because they do not flash but glow with an eerie blue or green light. Females of the blue ghost are pale yellow or white in color and lack wings (right in photo below). Males do have wings and can fly (left in photo below). Since they have not be studied extensively little is still known about them and their habits.
Scientists haven't decided whether this group should be classified as fireflies; while they share many characteristics of other species, members of the group Otetrinae don't emit light. They're considered very primitive forms of fireflies, and live primarily in Eurasia and North America.
There are more species of fireflies that live in Asia then anywhere else. In Malaysia for example, firefly light was so bright fisherman used the glow to help them navigate rivers at night. Unfortunately due to there decline this is no longer the case.
Fun Fact:No Glow
In the US, west of Kansas you'll only find firefly species that don't glow. Scientists are not sure why glowing fireflies prefer the eastern and southern parts of the country.
Fun Fact: Bats & Fireflies
Is firefly light a way to deter predators such as bats from catching them? Yes it does! Recently scientists have show that the flash does indeed deter bats from catching fireflies.
Essentials Field Guide to Insects
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Share Your Firefly Story
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How to Help Fireflies
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