Outdoors: Fireflies lighting up the Valley
Three weeks ago there was one, two and three. The next week there were five to ten. This week, yards are aglow with their yellow flashes from whence they got their nickname.
As robins signal the beginning of spring, fireflies (or lightning bugs) signal summer is upon us. These inch-long bugs are actually beetles, or nocturnal members of the family Lampyridae. Most fireflies are winged, which distinguishes them from other luminescent insects of the same family, commonly known as glowworms. And there are about 2,000 firefly species. They live in a variety of warm environments, as well as in more temperate regions, and are, as we know, a familiar sight on summer evenings.
Fireflies are nocturnal and during the day they spend most of their time on the ground. Although one has been clinging to my kitchen window during the day. At night they crawl to the tops of blades of grass and will fly into tree branches to signal to mates with their flashes. They love long grasses as it conceals them better and allows them a better vantage point for signaling at night. And when mowing the lawn, it may disturb them.
During the day, nocturnal adult fireflies hide in grass and low-profile plants. A nice variety of shrubs, high grass and low-growing plants will provide shelter. And did you know they are not found west of Kansas for some reason.
Adult fireflies live about two months or long enough to mate and lay eggs in grasses. Their larvae usually live for approximately one year from mating season to mating season, before becoming adults and giving birth to the next generation. Females deposit their eggs in the ground, which is where larvae develop to adulthood. Underground larvae feed on worms and slugs by injecting them with a numbing fluid.
The flashes seen are done primarily by females to attract a male. Sometimes a male will imitate them to attract females of their own species. And when the female shows up thinking its food, they find a mate. Fireflies are said to feed on plant pollen, nectar, insects, other fireflies or nothing at all.
And in case you’re wondering how they flash and glow, they have light organs that are located in their abdomens. They take in oxygen and combine it with a substance called luciferin to produce light with almost no heat. Then when they flash, they flash in patterns that are unique to each species. Each blinking pattern is an optical signal that helps fireflies find potential mates. Scientists, however, are not sure how the insects regulate this process to turn their lights on and off. Their flashes also serve as a defense mechanism to warn other insect’s that they are unappetizing.
If you’re seeing fewer fireflies, scientists say their populations are on the decline. It’s attributed to a combination of light pollution, pesticides and habitat loss. And it’s been said that when a field where fireflies lived gets developed, they don’t migrate to another field, they just disappear.
As a kid I’d catch them then let them go. I remember afterward that my hand would smell from a scent they must have deposited on it, which may be the luciferin. And although kids continue to catch them today, it’s recommended to not put them in a jar or bottle but give them their freedom so they can live to make a new generation so we can enjoy their brilliant flashes in the summer night. They won’t be flashing much longer, so enjoy the evening light show.