Nature Notes: Time of the Fireflies

The season of the insects
A large cicada-killer wasp at work in Sag Harbor Terry Sullivan

The never-ending mobbing calls of common crows and fish crows continue, but one rarely hears a songbird sing as we approach the halfway point of summer. Most of the birds have bred. The osprey fledglings are learning how to dive for fish. Turkey families are breaking up in preparation for the fall harvest. The architect Amado Ortiz, who lives on the west shore of Three Mile Harbor, snapped a photo of a maturish bald eagle working on a big fish while on a tree limb outside his window. All of a sudden four crows spotted it and angrily mobbed it until it flew off and landed on top of a sailboat mast. No wonder the accepted name for a bunch of crows is a “murder” of them.

It’s the season of the insects from here on in. The snowy tree crickets have sounded off outside my house once thus far. Usually they are out in full force chirping away at dusk every evening by now. They’re a little behind this year.

The handful of monarchs that have been around so far have a bumper crop of milkweeds, orange and common, on which to lay eggs. A few tiger swallowtails flap by now and then, but almost everywhere, the only common butterfly is the cabbage white, an émigré from Eurasia. Several of our biggest wasp-hornets — the much-touted cicada killers after their penchant for stinging cicadas and bringing them back to their burrows for the larvae to feed on — were busy tending to several burrows at the end of Middle Line Highway where it meets Round Pond south of Sag Harbor last Thursday.

The most spectacular insect of the season this time around is the firefly or lightning bug, Photinus pyralis, a genus and species name that aptly describes one. The common names miss by a mile; it is neither a fly nor a bug but a beetle! This half-inch black-winged insect with head and thorax trimmed with an orange edge is one of the few members of the class Insecta that can actually light up. Its enzyme luciferase causes a chemical luciferin to emit white light flashes when its nervous system gives the order. Both sexes can emit light pulses. In the dusky hours of late July and early August, they communicate with each other with their flashes, ultimately, if all goes well, ending in mating, and thus reproduction of the species.

My grandson Kevin from San Francisco will be a senior in high school this fall and is here with me for a few weeks to study the fish in Southampton’s freshwater ponds.

But while we were eating dinner two weeks ago around 8 in the evening we simultaneously watched the fireflies lighting up outside my front window and became so enamored with their antics that we decided to drive around the neighborhoods to see what kind of a season they were having.

Fireflies lift off the ground or a leaf’s surface and light up again and again. When you are counting their flashes, you easily lose track of them. Is it the same one repeatedly emitting light time after time, or is it one or others nearby? Soon, everywhere you look one is popping off. They start low, but by the end of the show, some of them have ascended as much as 20 feet in the air.

So we drove around in Southampton Town east of the canal and East Hampton Town west of Montauk on three different nights between 7:50 and 9:20, covering major roads such as Noyac and Scuttlehole Roads, the Bridgehampton-Sag Harbor Turnpike, and the like, but also almost all of the back roads we could hit in the two-plus hours we had allotted ourselves. You won’t see many fireflies along heavily trod highways such as Montauk Highway and the Sunrise Highway. Is it because of the confusion of vehicle lights along those well-traveled roads or does it have to do with the bad air quality along them?

Deer Run, a little residential road over a third of a mile long off Deerfield Road in northern Bridgehampton, produced 32 flashes along its shoulders in a matter of a few minutes, yet on the much longer parent north-south Deerfield Road connecting Montauk Highway with Noyac Road we saw only 14 flashes. Bianca Lane at the end of Old House Landing Road in Northwest, just about a quarter of a mile in length, produced 15 flashes from one end to the other, while on a short stretch of Sammy’s Beach Road connecting Bianca with Old House we saw 12 flashes.

The point I am making is that where there are residences with lawns and landscaping, there are lots of fireflies, but where the land is open, not so many, even when the road passing through the open land is not that heavily traveled.

The roads with the most flashes per mile were Deer Run with 85, Scuttlehole Road between Butter Lane and Brick Kiln Road with 75, and tiny Golf Club Drive in Amagansett with 52. Oddly, perhaps, Lazy Point and Cranberry Hole Roads, which comprise almost four miles and run from one end of Napeague almost to the other, produced only one firefly flash. Apparently, fireflies don’t like long isthmuses. But coming back west from a bad count on Napeague, as soon as we hit Bendigo, Abram’s Landing, and Fresh Pond Roads, firefly flashes skyrocketed.

In all four cases, the flashes started around 8 and were most frequently observed between 8:15 and 8:50. A count from my window on a calm Sunday evening went from the first flash at 8:08 to 8:43, during which 122 individual flashes were recorded.

Lao-Tzu, the venerable Chinese philosopher who wrote the “Tao Te Ching” and is known as the father of Taoism, was reported to have said that you can know the world from your home as well as you can by traveling around it. As far as fireflies go, he was apparently correct.