Lightning beetles light up fairyland

Imagine our amazement when summer came to our new house and we discovered hundreds of lightning beetles in our “backyard.”

Let me explain. Bill and I downsized and now have a little more than 2 acres — down from 10 1/2 — but we have a 100-plus-acre farm field in our backyard. This year it is corn. But at night — it is a fairyland!

As soon as the chimney swifts go to bed, the bats come out and I watch them and the lightning beetles as they seek out mates.

Though they are called lightning bugs, or fireflies, they are neither, but belong to the family Lampyridae. They are true beetles, consisting of 170 species in the U.S. and Canada.

They have a complete life cycle, meaning they have egg, larva, pupa and adult stages. Adults hatch out in June or July, and go on the hunt for mates.

When they mate, the female lays eggs in midsummer, then larvae hatch and live in the ground in moist areas eating insects, slugs, and snails. They hibernate in the soil, then pupate in the spring, and adults hatch out to complete the cycle.

They fascination is with the bioluminescence or ability to make light, which is two enzymes, as chemicals that mix with oxygen to make “cold” light. This light is nearly 100 percent light energy, no heat (Iowa State University). As well, another chemical makes the lightning beetles taste bad to predators, so the flash of light means “I taste bad!”

As lightning beetle males sweep the backyards, fields and open areas they search for females. Males may eat a bit of pollen or nectar but many adults never eat at all, as they search out the compatible flashes of light signaling the mate. The flash is genetically encoded to each species as a fixed pattern as part of the courtship ritual. The patterns of flashes, duration, numbers, intervals, motion and height all are distinctive. Larvae and females in or on the ground are the term “glow worms,” as they signal back.

Two chemicals produced by the lightning beetles are proving useful in cancer, cystic fibrosis, multiple sclerosis and heart disease. There are also instances of synchronized species (one of 19 that scientists know of in the park) being studied in Pennsylvania and the Great Smoky Mountains National Park.

There have been increased populations in several areas. We don’t really know why this is happening. Most of it may be related to the loss of habitat, including leaf-covered areas where the larvae thrive. Another theory is the natural cycles of insects. Insects go through periodic cycles of large populations, then back to very low populations. Lightning beetles may have a very long cycle that we do not yet understand.

For great photos and details of these beetles, go to http://go.osu.edu/lightningbeetles.


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