Take Five: Are there more fireflies this summer? We ask an insect expert
This article first appeared in the St. Louis Beacon, June 21, 2010 - Despite rumors to the contrary, lightning bugs are not endangered, and if you have any doubt, go find an empty pickle jar and then spend an hour in your backyard or in a park tonight. Lightning bugs -- or fireflies, if you prefer -- are out in full force, and there is absolutely nothing more cool on a hot Midwestern summer night than catching a jarful of flashing beacon bugs. (Smile.)
For the facts on fireflies, we turned to Richard Houseman, an associate professor in the plant sciences division of the University of Missouri. Houseman, who researches the behavior of insects in human environments, says last summer's cool, wet weather and generous rains this spring have probably boosted populations in areas where they have not been as noticeable in previous summers.
So, there are more fireflies in our backyard, but not in yours?
Houseman: Here in Columbia I wouldn't say I'm seeing more than usual. They're pretty abundant especially on the outskirts of town and into the country. In certain environments you're going to see localized higher abundance, no change in other areas and maybe lower abundance in some areas if there is extreme moisture and it gets too wet.
There are some things that affect them, and weather can have an influence on them just like it can on other insect groups.
Did you know?
Some lightning bugs of the genus photuris will prey on other species of lightning bugs by mimicking their flash patterns, according to associate professor Richard Houseman of Mizzou.
"The female will answer the males of another species, and when the males come in to mate with her she chews them up and eats them," he said.
"So you never know."
They need slightly moist areas. They're not aquatic insects: They don't live in a stream, for example, but they do prefer to be on vegetation that grows in areas where there is some moisture. They are moisture-loving. We had a pretty moist, cool summer last year, and those immatures that were developing last year would be the matures this year.
Are they endangered in urban areas?
Houseman: Some of their habitat has probably been reduced in urban areas like St. Louis.
It's more of a localized reduction. They're not rare by any means, and they're not threatened or endangered. But you can have reductions in local populations due to overall human activity. Then you have a good year in those certain spots and if they were able to hang on in that area and are able to produce plentifully you get what appears to be a resurgence.
Which is more accurate: ladybug or firefly? And, besides the light show, what are they good for?
Houseman: They are neither flies nor bugs. They are beetles.
The larvae are predators and feed on small insects and even on small snails. They play an important part in natural food webs. They're not considered to be a predator specifically on any type of pest insects, but they probably do eat some pest insects.
But they are one of the more inviting insects. They get kids interested in insects and natural things. Fireflies are wonderful that way because there's a curiosity about them and anything that spurs that curiosity can lead kids to learn more about them. They are kind of spokesmen for the insect world.
It used to be that everybody thought that every insect was bad, but there is a growing part of the population that realizes that there are beneficial insects that do good things, and 99.9 percent of the insects out there are either harmless or beneficial and not something that we need to immediately kill or get rid of.
Is the flashing really a mating call?
Houseman: The flashing is related to mating. The female is signaling to the male of the species. Once they get through the mating cycle, and they lay their eggs, they die.
Different species will flash at different times. Typically, it's a late spring, early summer phenomenon. Then most of the species are done for the year.
There are 66 species in North America, according to the reference I have. If you go out into the evening and you start seeing flash patterns, there may be a half-dozen or more species that you are seeing.
Their signals aren't just like Morse code, they also fly at a certain direction or rate of speed and that movement is combined with the flash pattern. Some flash while they are sitting on vegetation. Some will start with a long flash, moving horizontally and then moving upward, like a backward letter L. It's more of a trail of light than a blip of light.
So, we take it that lightning bugs only mate at night?
Houseman: Nighttime is the right time for fireflies.