Why Do CNY Fireflies Light Up?

Natures natural twinkle lights are fireflies. When you see your yard or a field full of them, it's like your own personal light show. Find out why they flicker and how their flash pattern helps them.

Who remembers catching fireflies on hot summer nights? You would put them in a jar in your bedroom then let them go the next day. A long time ago, people made money with firefly tours in marshes and forests. Yes, they're a magical part of summer, and if we aren't careful, they will be gone forever soon. But more on that in a minute. First, why do they light up?

Scientific American tells us 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. Studies show that female fireflies choose their mates with specific male flash pattern characteristics. Higher male flash rates, as well as increased flash intensity, are more attractive to females in two different firefly species.

The firefly population is diminishing quickly all over the world. Did you know there are over 2,000 species of fireflies in the world? And more than 200 varieties were found in the U.S. However, many of those have disappeared. Experts believe they are dying out due to the development of their natural habitat and light pollution.

Fireflies prefer warm, humid temperatures near water like a pond, stream, or a river. They flourish as larvae in rotting wood around water, and most stay where they are born. Logging, pollution, the increased use of pesticides, and human traffic all contribute to destroying the firefly habitat.

Artificial light pollution is another notable factor in the disappearance of fireflies. Male and female fireflies must use their flashing lights to communicate and speak the 'language of love' for mating and safety. They can't do that when it's always bright. We can do our part to help by turning off outside lights; those who live near a wetland should leave some taller grass to give fireflies a place to live and avoid using pesticides and weed killers.

There is much more information about disappearing fireflies and what we can do to help at Firefly.org.