We often think of the “food chain” in the natural world in linear terms: this eats that, which in turn, is eaten by the other. But today’s subject proves that chain is a little more like a web. The species we’re talking about today feeds on the most dangerous game, the apex of apex predators…us. And the species that prey on us? Mosquitos, of course! We recently spoke with Sarah MacGregor, an entomologist and founder of Dragon Mosquito Control, help us learn more about them.
We often think about mosquitos with a capital-M, as if there is just one kind of mosquito. But there’s actually lots of different species. MacGregor has counted over 45 species in New Hampshire with different habits and different habitats. There’s the house mosquito, the salt marsh mosquito, tree-hole mosquitos, rock pool mosquitos and cattail mosquitos among many others. While these common names refer to where you might find these insects, they also refer to distinct species of mosquito.
It may be poor consolation when a plague of insects descends on your head as you tend your garden, but it bears remembering that only a small percentage of the mosquitos in your back yard want your blood. Firstly only the females will draw blood, the male mosquitos feed entirely on sugars derived from flower pollens. And the females drive to bite a sanguine animal is only present when they’re ready to lay eggs. Additionally many species of mosquito feed exclusively on amphibians, fish, birds, reptile and will not bother to make a withdrawal from human veins. Tragically there are a few that are opportunists and will bite anything nearby, be it a bird or a deer or a human, “and those are the ones that tend to carry diseases,” says MacGregor.
The variety of names for mosquito species is one indication of how versatile these insects can be. Another is the variety of places where they can breed. There are a few limiting factors: they require water and that water needs to be static. As MacGregor points out, mosquito larvae are not strong swimmers and can’t handle a current. But beyond that they require little else, so salt marshes, vernal pools and ponds are all places where you’ll find mosquito eggs hatching out and larvae developing. Says MacGregor “What’s so fascinating about mosquitos is they’ve pretty much adapted to most habitats. One of the nastiest catch basins that I ever [tested] was full of cigarette butts, and it was loaded with mosquito larvae.”
Another fascinating aspect of mosquitos is the durability of those tiny eggs. Mosquitos lay their eggs in the fall among leaf litter, on the edge of rocks anywhere they can be expected to be born up by spring melt. “The eggs are washed into the water, once the snow and ice melt, or after a rainfall or after a tide.” But if an egg misses the boat and spends the spring in more arid conditions, it doesn’t shrivel up and blow away. McGregor said she’d heard of eggs lying dormant for 8 years before producing a larva.
Once mosquitos hatch and pupate, they become the objects of frustration and fits of pique among bipeds all over the state. But we all know at least one person who insists that they are singled out by these fair weather denizens. As it turns out there may be some truth to that. As MacGregor points out that while some species of mosquito are opportunists and will bite what or whoever is close at hand, they can be attracted by scents (like hair product, skin cream even laundry detergent), metabolites (molecules we produce as a part of out metabolic process) and carbon dioxide. So depending upon your diet, ablutionary routine or even your respiratory rate you may be a more attractive target than others.
McGregor reminds us that long pants and sleeves are the best deterrent. Since that’s not welcome advice during the triple-H days of July and August, she prizes deet as the most effective spray to keep mosquitos off your skin.