Just in time for summer, which arrives at 7:28 a.m. on Monday, the fireflies are back. In my mind, flickering fireflies -- or lightning bugs -- are the essence of a Georgia summer night.
In recent years, fireflies have been scarce or absent altogether in many metro Atlanta neighborhoods, including mine in Decatur. Blamed for their disappearance were some unusually hard, spring freezes and a severe drought. Fireflies are soft-bodied beetles, and not real flies, and can easily dry out in prolonged dry spells.
Now with rainfall back at adequate levels, the blinking insects are again lighting up our yards. Whether they’re back in full force, I’m not sure, but there is definitely more of them now than in recent years. Entomologists speculated a couple of years ago that it could take several years for the insects to rebound to their earlier levels.
There are, of course, many other icons of a Georgia summer: Whip-poor-wills calling after sundown, plump, juicy tomatoes ripening in the garden and nighthawks darting about the evening sky. But without fireflies flashing at night, summer is not the same for many of us.
When I’ve had my fill of the evening news and its daily digest of disaster and mayhem, I like to go onto my front porch and watch the fireflies in my yard. There's something relaxing and reassuring in watching the nightly spectacle of tiny blinking lights.
University of Georgia entomologist Nancy Hinkle noted that “the fireflies patrolling are males, scanning for mates. In their courtship, females sit on vegetation and send out their light signals, which males cue in on.”
Within the insects’ light-producing organs at the rear of their abdomens are two chemicals that combine to produce light. It's a process that's virtually 100-percent energy efficient, so no heat is generated. The resulting light may be greenish, orange or yellow.
Georgia actually has several dozen firefly species, ranging from less than half an inch to almost an inch long, Hinkle said. The most common species are black or gray with white, yellow and red markings. Each species has a distinctive flash pattern, lasting for a specific time and with a definite interval between pulses. This allows the sexes to identify one another.
“Some female fireflies mimic other species' flash patterns, luring in foreign males,” she added. “These predatory females then eat the hapless males.”
IN THE SKY: Monday, the first day of summer, also will be the longest day of the year. On Tuesday, the days start getting shorter until we reach the year’s shortest day, Dec. 21, the first day of winter.
The moon, in first quarter, is in the south at sunset and sets around midnight, said David Dundee, Tellus Northwest Georgia Science Museum astronomer. Mercury is very low in the east just before sunrise. Venus is low in the west just after sunset and sets in the west about two hours later. Mars sets in the west after midnight. Jupiter rises out of the east about four hours before sunrise. Saturn is high in the east at sunset and appears near the moon tonight.