Greenhead Flies | What are Greenheads?
Come mid-July in, the dreaded greenhead flies — commonly known as greenheads — descend upon the beaches of New England. Learn more about these hungry, bloodsucking flies that are fierce enough to destroy vacation plans in one swoop.
Greenhead flies, named for their large, bright green eyes, can be found in the coastal marshes of Eastern North America. Unfortunately for us, that means they love New England’s beaches. Knowing about these pests can help you plan your next beach trip the safe way – away from the painful bites of greenhead flies.
The wild serenity of the salt marsh stretches from Maine to Florida. It is a world caught between worlds, a lovely transitional swath of emerald grass that snakes along the Atlantic coastline, occupying a territory somewhere between sea and solid ground.
This line of demarcation between solid and liquid is neither and both. The ground of the salt marsh is springy, like walking on a lumpy trampoline. Water oozes up through tufts of matted grass, potholes lurk beneath seemingly solid ground.
Who inhabits this spongy world? Apart from the occasional deer, there are turtles, assorted birds, mice, and, once in a while, a rabbit, a raccoon, or an otter, mostly just passing through. Which means it’s slim pickings for one small, hungry inhabitant, whose appetite revs into high gear ’round about mid-July.
Like ripening fruit at the moment of perfection, Tabanus nigrovittatus emerges from the salt marsh at summer’s midpoint. She has just laid her first batch of eggs. Two hundred or so microscopic dots, but who’s counting, because right now she’s out of her mind with hunger, and it’s time to get down to the business at hand. Her first blood meal. Ever. In her young adult life she’s never had a solid meal, subsisting mostly on nectar, preferring to wait until the whole egg-laying business is behind her. By doing so, she ensures that the precious bloodline will continue, that the next generation of greenhead flies–as she is more commonly known–will be born. But right now she’s paying the price. And there’s not a thing to eat.
A stone’s throw from the unearthly beauty of the salt marsh, some of the great New England beaches sprawl beside the Atlantic, baking in the sun: Crane Beach, in Ipswich; Plum Island, off the coast of northeastern Massachusetts; Hammonasset Beach, unfurling along the Connecticut side of Long Island Sound. A brilliant blue sky stretches overhead; a faint breeze ruffles the grasses. Perfect beach weather. A great day to fly. Her dazzling green eyes casting about, she makes a beeline for the water. The sand up ahead is swarming with warm, scantily clothed bodies, fairly bursting with reservoirs of succulent human blood.
“Greenheads,” says the blond boy barricaded in the entrance booth at Hammonasset Beach State Park. He slides open a window and points to a squashed bug taped to the side of the building. “They’re pretty bad today. You may want to think about it.”
Given the size and spread of the flattened insect, “pretty bad” seems like a PR understatement. The little torpedo is more than half as long as my thumb, and even mashed up it’s easy to imagine hordes of greenhead flies making for the beach like vacationers racing to claim their patch of sand. Like most beachgoers, tabanids prefer warm, sunny days, and it is, of course, an especially beautiful July morning, without even a hint of breeze. The sun is already fierce, the distant sand shimmers with promise, and the sea is as blue as the Aegean.
But a face-off with greenhead flies? Their size makes them fairly immune to bug repellent, and slathering on DEET isn’t a very appealing option. Do I want to spend a day swatting these things? I squint at this poster child for a bad day at the beach, weighing the pros and cons. In full knowledge that at this very moment, a similar scenario is playing out, up and down the East Coast. Cars backing up, just as I’m about to do, turning around and heading home. Or at the very least, somewhere far from the coastal salt marshes.
And that’s when I get curious.
What’s up with this bug? Clearly it’s a robust type of horsefly (the name is a tip-off), and it certainly outweighs its relative the deerfly, although both biters belong to the same fly family, Tabanidae. And “greenhead” obviously refers to its enormous green eyes, laced with bands of iridescent red or purple.
Please Note: This information was accurate at the time of publication. When planning a trip, please confirm details by directly contacting any company or establishment you intend to visit.