FIREFLIES, THOSE TINY SUMMER LIGHTS
Fireflies, also known as lightning bugs, do give special charm to warm nights. They are actually elongated soft-bodied beetles possessing "tail lights" -- segments near the ends of their abdomens with which the insects are able to produce light. There are 136 species of beetles known as fireflies in eastern North America. Here in Minnesota we ordinarily see these tiny lights in the dark from late May through July. Wetlands, wet ditches, tall grassy spots, forest edges, cornfields, and sometimes lawns near these other areas are good places to observe them.
The flashing is a recognition signal enabling the sexes to find each other. Each firefly species has a characteristic flashing rhythm. Typically a male emits flashes of yellowish light at intervals of a few seconds while he flies a few feet above ground. Females wait on top of low vegetation and if a flashing male comes within about 6 feet, she flashes back. The exact number of seconds between flashes serves to distinguish the species. So the male will only approach a light if it blinks at the proper intervals.
The light emitted by these insects is unique in that it generates no heat. Nearly 100 percent of the energy is devoted to the light itself.
JIM GILBERT
