Last night, my Dad called for me to come look outside. We had just had a short thunderstorm & it was dusk. What he wanted me to see were the lightening bugs (fireflies) that were flying around in the yard. I had just commented the other day that I hadn’t seen any recently & thought it was odd. I distinctly remember catching them at night, not dusk. And he remembered dusk, hence why he was looking for them at that time. So being the daughter of science teachers, I had to do a little digging (see article below). Looks like we were both right…some species come out only at dusk, some only when it’s completely dark. In all species, it’s only the male that we are seeing flying around, this is part of them attracting a mate. Now, as for why I’m not seeing any after dark, that’s probably due to several factors. I’m thinking that city lights, insecticides, & lose of habitat are the main contributing factors.
Whatever the case…I do miss taking a jar out & catching a few…just to marvel at them for a short time before letting them go.
I received a letter from an older gentleman expressing how much he missed the lightning bugs he used to chase as a child. He still sees them, but not in the huge numbers he remembers, when a kid could fill a jar with them in just a few minutes. A young woman also asked me some questions about lightning bugs, including whether there used to be more of them. Since these amazing insects are active right now, this is a good time to talk about them.
Lightning bugs or fireflies are beetles in the family Lampyridae. They are narrow, medium-sized beetles with rather soft, leathery wing covers. They are black or brown with yellow or red markings on the pronotum (the plate-like segment that covers their head), and some have narrow yellow lengthwise stripes.
They produce their light by a chemical reaction in their bodies. For a long time, scientists did not understand how light could be produced without heat, but they finally figured it out. Now the process is used in all sorts of medical and industrial processes, including the “light sticks” that kids play with.
Lightning bugs can light up during all stages of their lives, including the larvae and pupae. In some species, even the eggs glow. In the immature stages, they light when they are disturbed, which probably scares their enemies. However, for the adult beetles, the lights are all about mating.
There are about five common genera of fireflies in the eastern United States and one to several species within each genus. I do not know how many we have in our immediate area. They are predators of snails and soft-bodied insects, both as adults and larvae, and are considered highly beneficial.
One question I had was whether the lightning bugs in the trees are a different species from those flying around.
They might or might not be, because whether they fly or sit still has to do with their sex, not their species.
Each species has a particular light pattern. That enables males and females to find each when there are other species lighting, too. The light patterns are different in several ways. They can be different colors. There are different numbers of flashes, such as single flashes, double flashes, or a series of flickering flashes. The flashes might be timed a certain number of seconds apart (I guess lightning bugs can count). Some light at dusk, others only after it is completely dark. Some flash while flying upward, some while flying in a straight line.
The lightning bugs you see flying around are the males. The females stay in one spot. That makes it much easier for them to find each other than if they were both flying randomly around.
Males fly around flashing, advertising their presence to the females. Females sit in a tree, bush or on some other perch. When they see the light of a male of their species, they answer with their own light. When the male sees the answering female, they have a dialog of lights and then he lands.
Lightning bug populations are down for many reasons, probably all of them caused by humans. For one thing, people have this pathological fear of darkness and plant lights that burn dusk to dawn all over creation. As you might expect, these little creatures that need darkness for their mating lights to show up will not be able to find each other. Then there is the green-lawn mania that causes people to bombard the ground with insecticides and herbicides. Insecticides kill good insects, too.
Most of all, there is simple habitat destruction. Lightning bugs breed in open woods and meadows and those places are quickly falling to the bulldozers. The adults don’t fly far from their homes, so once their habitat is destroyed, they don’t go out and colonize new places (if there were even any new places to colonize).
You can help if you will only turn off your outdoor lights when they are not absolutely necessary during the lightning bug’s short season.
You can also help researchers by joining Firefly Watch, a free program of Boston Museum of Science that you can participate in via your computer. All you have to do is spend a few minutes a week watching the insects, then send in your data. Their web site is: www.mos.org/fireflywatch/home
Send your insect questions to Claire Stuart by e-mail at bugl...@wv.net or write her (with self-addressed stamped envelope) in care of Living Section, The Journal, 207 W. King Street, Martinsburg, WV 25401.
