Summer, of course, is the time for observing and catching fireflies.
Did you know, however, there are more than 120 species of fireflies in North America and there are numerous species in our area?
Not all fireflies flash, but the ones that do are divided into three main genera: Photinus, Photuris and Pyractomena. Within each genus there are numerous species. Photinus fireflies are most common in our area. Each is about one-half inch in length, and produces a yellow or yellow-green flash. Photuris fireflies, also found in Illinois, are about one inch in length and have a dark-green flash.
The flashes we see in our yard are an integral part of the reproduction process. Male fireflies flash while patrolling an area for a mate. If a female is impressed, she answers by flashing from the ground or from a perch. If a female does not respond with a flash, the male, unable to find her in the dark, must continue his quest. Since adult fireflies live only two to four weeks, there is no time to waste.
Each species of firefly has a distinctive flash pattern, varying in a variety of ways: color, length, number of flashes, interval of time between flashes, time of night they are active and flight patterns. In my backyard during the past few weeks, there have been fireflies displaying a variety of flash patterns — number of flashes, length of intervals between flashes, flight patterns — as well as yellow, yellow-green and green flashes.
Some fireflies casually fly around, others streak about like meteors or quickly fly in a zig-zag pattern.
It has been amazing to watch this fantastic light show. I estimate six to eight species have been present in my backyard so far this summer. While the common Photinus Pyralis — the species often caught by children — appears when dusk approaches, other species are more likely to be seen after 9:30 p.m. The Pyralis moves in a “J” pattern when it flashes, making it easy to identify and catch.
I encourage everyone to spend time this summer enjoying the light show our fireflies are putting on. To learn more about fireflies and to be part of ongoing firefly research and conservation efforts, visit the Firefly Watch website through the Museum of Science of Boston at legacy.mos.org/fireflywatch/.
