Sex on Six Legs_ Lessons on Life, Love, and Language From the Insect World - Marlene Zuk [6]
Insects are starting to answer the question of "What does it take?"—to have a personality, to learn, to teach others, to change the world around them—with the humbling and perplexing answer, "Not much." Humbling because they do these things with brains the size of a pinhead, and perplexing because if that's all it takes, what does that mean for us, with our gigantic forebrains and exhaustingly long periods of childhood dependency?
Insects Are Essential
If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.
—E. O. WILSON
WE ALSO keep coming back to insects because they are, however we may feel about them, extraordinarily important to the earth's functioning as well as our own. Insects help aerate the soil by burrowing through it, and nourish it by leaving their droppings. They eat dead plants and animals that otherwise would clutter up the planet, and release the nutrients back to the soil. They control populations of other invertebrates and vertebrates alike, by eating them or their food or by making them sick. In turn, insects provide food for other organisms. Perhaps most critical, insects are key pollinators of commercial and wild plants alike. All of these activities are performed to some extent by animals other than insects, of course, but the sheer magnitude of insect numbers means that they could not be eliminated without leaving a hole so large that, as Wilson says, the rest of the world's organisms would be unable to continue their lives.
To make the worth of these ecological services, as they are called by scientists, more concrete, in 2006 John Losey from Cornell University and Mace Vaughan of the Xerces Society for Invertebrate Conservation calculated the economic value of four crucial tasks performed by insects: pollination, recreation, dung burial, and pest control of animals that eat crops, including other insects. They chose these categories because of the availability of data, not because of their perceived "importance," and acknowledge that the amount is almost certainly a conservative estimate. The total bill? Over $57 billion in the United States alone, and that just includes so-called wild insects, not domesticated honeybees or silkworms or other species that are reared commercially by people.
The recreational aspect of insects is not, as you might initially think, due to people wandering around the countryside collecting butterflies to be pinned under glass. Instead, Losey and Vaughan examined the importance of insects to hunting, fishing, and wildlife observation, including bird-watching. Fish need to eat insects, and we use insects to catch them. Game birds such as grouse and pheasants rely on insects as food, as do waterfowl such as geese and ducks. And without grubs, flies, and beetles, all those lovely harbingers of spring—the warblers and flycatchers, woodpeckers, and swifts—would perish.
Dung removal is probably not a service to which people give much thought, but our own sewage issues aside, everyone produces waste, as the children's book notes rather more colloquially, and it has to go somewhere. If it weren't for insects, that waste would just linger on the surface of the soil or in the water, tying up nitrogen that could be enriching the soil, and providing a breeding ground for disease-causing organisms. Cattle also tend to shun grass that has been sullied by dung. By burying manure underground, dung beetles come to the rescue in many parts of the world, including the United States. They were introduced into Australia, where they do not occur naturally, to help process the massive quantities of dung produced by the cattle brought to that continent in the late eighteenth century. A friend of mine in Perth, Western