It’s July, the month of abundance- fireworks, beaches, fresh produce, outdoor concerts, midsummer and my favorite evening entertainment the exquisite natural pyrotechnics of the fireflies accompanied by the melodious chirping of our native gray tree frogs Hyla versicolor.  It does not get any better.

Scientific illustration by Arwin Provonsha, Purdue Department of Entomology

Also known as lightning bugs, fireflies are neither bug nor fly, but beetles with two pair of wings, and large eyes that help with night vision while flying and lighting up the summer skies.  Fireflies have specialized light organs under their abdomens and produce a compound luciferin that when combined with oxygen undergoes a chemical reaction know as bioluminescence that produces light with almost no heat.

Although other insects can produce light, fireflies are the only insects that can flash their light on and off in distinct signals. Even the eggs and larvae of some firefly species glow. Hence the name “glow worm”.

"Lightning Bug" Larva Photo by Gerald Lenhard,

While there are around 2,000 species of fireflies, in New England fireflies fall into three main groups, Photinus, Pyractomena, and Photuris. These  can be identified by their fairly distinctive flash patterns, color, and location.

Photinus firefly flashes yellow- green and is the most common firefly in our yards.

Pyractomena’s flash is said to appear like flickering campfire embers with and amber-yellow flash.

Photuris has a bright, dark green flash and is the most difficult to identify of the three.

The male fireflies flash while flying around patrolling an area.  The females perch on the ground, in a shrub or tree and decide whether or not to answer the flash of the male.  If the female is not interested she does not flash and the male cannot find her.

Females deposit their eggs in the ground and the larvae hatch in about 4 weeks. The larvae stay in wooded areas and around sources of water, in New England they overwinter in this stage. Sometimes adolescent lightning bugs make small flashes while on the ground.

Research shows that the number of fireflies is decreasing probably due to habitat destruction.  To encourage these nightly summer pyrotechnic artists in your yards try some of the following:

Minimize outdoor lighting; change your outdoor lighting to lights that operate as a motion detector.

Adult firefly (Photo: BartDrees, Extension Entomology, Texas A&M University)

Install lights that are low to the ground and that point straight down instead of shining in all directions.

Don’t use bug zappers outdoors. They create light, but also can kill beneficial insects. Install a bat house or purple martin house to control mosquitoes naturally.

Don’t use chemical fertilizers, or broad spectrum pesticides. These can poison fireflies and other beneficial insects. Use compost, compost tea, and fish and seaweed mixes to fertilize.  If you have to use pesticides, use less toxic, organic and biological controls, insecticidal soap and oil spray. Look for lighting bugs before you spray.

Adult lightning bugs rest during the day in tall grass, vegetation, or low tree branches so they can stay cool.

Rich, organic soil encourages earthworms, snails and other soft bodied animals, which lightning bug larvae eat. If you have a manicured lawn, create a small natural area for a lightning bug habitat.

The Museum of Science, Boston is teaming up with researchers from Tufts University and Fitchburg State College to track and study these amazing creatures.  For more interesting facts on fireflies, how to identify them and to get information on how to help with this study check out Firefly Watch at:

A research scientist at UConn has developed a theory to explain why fireflies flash in unison. To read about this research go to