Into the Outside with Fireflies

Photinus by Don Salvatore

Photinus by Don Salvatore

I grew up in the suburbs of New Jersey in the 1970s. As a child I remember summer nights filled with fireflies in the back yard. I was so transfixed by these little creatures! They had little flashlights on their tiny bums and they would dance in the nighttime breeze, flashing their little lights to some silent tune, as if only they could hear the waltz.

Now, every June I await for the fireflies to begin their summer ritual. Frank and I have so few where we live so sometimes, to get my fix, we travel all the way to Montague where I know of some choice fields where the action goes on for hours.

Did you know there are two dozen species of fireflies in Massachusetts alone? I sure didn’t; not until I took a citizen science class on fireflies at the annual Massachusetts Environmental Education Society (MEES) conference this year. I knew there where at least two, but wow, two dozen? Twenty-four species of fireflies was phenomenal news to me. And each specie that does flash has its own special signal.

Now before I get into the natural history and science of fireflies, I just want you all to know that becoming a citizen scientist for firefly counting can be done, not just by adults, but by kids as well. What a great reason to stay up just a wee bit passed bedtime – “Mom, Dad, can’t go to bed right now. I have an important duty to perform as a citizen scientist; I am going outside, to count firefly flashes.”

Firefly Science

Of the twenty-four firefly species in Massachusetts, there are three that flash. Yes, you read right, not all firefly species have little flashbulbs on their bottoms; only three (that we know of thus far) do. So that firefly-looking insect you saw during the day earlier this spring was probably the Winter Firefly.

A firefly, also known as a lightning bug, is neither a fly nor a bug but a beetle. To get to know this order of insects look for the tough front wings that meet in a straight line down their back. A pair of thinner wings is kept folded under the top pair when this creature is not flying. Like all insects, fireflies have three main body parts: the head, thorax, and abdomen. Being an insect they also have six legs and antennae. Those that have the light-emitting organs on the lower parts of their abdomen are able to flash because of a chemical reaction called bioluminescence. Ever bite down on a Wintergreen Lifesaver candy and seen that spark in the dark? Same concept; a chemical reaction takes place that creates this “cool light”. Cool, huh?

Each flashing firefly has its own language, or secret code, to communicate with others of its kind. We used to understand that each firefly was just out there flashing to find a mate. We now are learning that it is not just same specie partners that are attempting to match up to mate and make more fireflies. There is also intrigue taking place in those bushes out back.

Trickery in the Tall Grass

While the Photinus male is minding his own business trying hard to attract a female of his own kind, the Photuris female, who is about twice the size of Photinus, has other plans. She is hungry. So to attract a meal, she mimics – pretends to be – a Photinus female by copying the Photinus female’s answering flash. The Photinus male gets all excited, “hooray, I have found my sweetheart!” Only to be set upon and eaten when he alights on the leaf or grass-blade.

To make matters more complex the Photuris male, trying to attract a Photuris female will also mimic the Photinus in hopes that he can lure his own specie by tricking her into thinking she is going to get a meal but instead the Photuris male arrives hoping his affections will be reciprocated by the Photuris female. And that is not all; a Photinus male, after having arrived successfully at the doorstep of a Photinus female, will ward off other potential suitors by mimicking a Photuris female, mimicking a Photinus female, but one who accidently gave herself away as a Photuris. Wow! What complexity! What adventures are taking place outside our windows in the gloaming.

Finding Fireflies

If you want to find fireflies that flash, first you need to head outside at dusk. Yes, when the mosquitoes are descending upon you in hoards. Photinus, Photuris, and Pyractomena can be found in moist meadows and fields. Their larvae need moist soil to grow in and soft-bodied invertebrates to eat, so an ideal habitat for youth and adults consists of a meadow or large yard with shrubs and uncut grass which is surrounded by forest.

If you can even keep just a patch of your grass uncut and some of your garden a bit wild, your chances increase that fireflies will find your yard an appealing habitat.

Games you can play with other families and neighborhood kids on summer nights

Flashlight Tag: Depending on how many participants you have enlisted, you may want to have one or two “it”. In this game only the “it” has the flashlight. Decide upon three to four bases that the participants have to get to, in no particular order. This way no one can just stay hidden but have to find a way to sneak in, tag a base, and leave. The object of the game is for the players not to get tagged with the light of the flashlight while tagging each base. After a player has successfully tagged all the bases s/he can hide nearby and wait. The object for “it” is to shine their flash light on other players. Players who are tagged sit out until the next round. The round is called after there is apparently no one except “it” running around.

Mimickers: For this game, all players need their own flashlight. Half the players are Photinus and the other half are Photuris. Each group separates, decides on specific flashes and what those flashes mean. For example, the Photinus team may decide that two quick flashes mean “come here” and that the proper response would be to flash three quick flashes. Spread out in a large area; this can be school grounds, someone’s backyard, a patch of woods, or a field. The object for Photinus is to find one another again, at least in pairs. The object for Photuris is to figure out through observation, what the various signals Photinus are using and lure in a Photinus. If a Photinus is tricked into going to a Photuris, the Photinus is out and can stargaze through this round.

Learn more about Fireflies
General nature activities, including fireflies: http://www.backyardbiology.net/
Firefly facts, photos, stories http://www.firefly.org/
Firefly Flash Chart: https://www.mos.org/fireflywatch/flash_chart
Into the Outside with Fireflies Family Outing, Saturday, June 16, 8:00 – 9:30pm with Arianna Grindrod of Earthwork Programs. For details go to: www.earthworkprograms.com