‘Something in the insect seems to be alien to the habits, morals, and psychology of this world, as if it had come from some other planet, more monstrous, more energetic, more insensate, more atrocious, more infernal than our own.’
—Maurice Maeterlinck, Belgian playwright, 1862-1949
Such animosity hardly seems justified. Of the approximately 9 million species of insects on Earth—the vast majority undiscovered and unnamed—only about 11/2 percent do us any harm. The rest have either no direct impact or provide some very obvious and indispensable benefits to humans. They pollinate plants, including 80 percent of the world’s 94 major food crops, as well as vast tracts of tropical rain forest. They decompose our dead and all the waste that animals and plants produce, from dung to discarded skin, feathers to hair, dead leaves to rotten wood. They protect our harvests by eating the pests and the weeds that would destroy them. They are food for birds, frogs, reptiles, fish, and mammals—including, wittingly and unwittingly, humans. They aerate and enrich the soil by digging tunnels and carrying nutrients down from the surface. That, in turn, helps prevent erosion and runoff into rivers and streams.
Mosquito
It isn’t hard to understand why the mosquito is so reviled. Elegant, dainty, and deadly, it is the most common of all blood-sucking arthropods and the most important insect carrier of human disease, transmitting not only malaria but also yellow fever, dengue, West Nile virus, encephalitis, and the tiny worms that cause elephantiasis. But mosquitoes, with 3,550 species, have their place in the web of life. Birds, bats, fish, and many significant wetland species, including dragonflies, feed on them. Anopheles mosquitoes—among them A. stephensi, shown here—have arguably changed the course of human history. Over the centuries they have killed untold millions with the aid of the malaria parasite, Plasmodium, which they inject into blood along with their saliva. Prior to the widespread use of quinine, in fact, it was mosquito-borne malaria that largely protected Africa from European colonists, who died from the disease in such high numbers that the west coast of Africa was dubbed the white man’s grave. Another species, Aedes aegypti, carried yellow fever to the New World with the African slave trade and helped drive France to negotiate the Louisiana Purchase in 1803.
