While ants exist in just the right numbers for the rest of the living world, humans have become too numerous. If we were to vanish today, the land environment would return to the fertile balance that existed before the human population explosion. Only a dozen or so species, among which are the crab louse and a mite that lives in the oil glands of our foreheads, depend on us entirely. But if ants were to disappear, tens of thousands of other plants and animal species would perish also, simplifying and weakening land ecosystems almost everywhere.

People would rather believe than know.

Women are extraordinary in lacking the estrus, or period of heat. The females of most other primate species become sexually active, to the point of aggression, only at the time of ovulation. Why has sexual responsiveness become nearly continuous? Unusually frequent sexual activity between males and females served as the principle device for cementing the pair bond.

Ants make up two-thirds of the biomass of all the insects. There are millions of species of organisms and we know almost nothing about them.

The ant world is a tumult, a noisy world of pheromones being passed back and forth.

Consider the nematode roundworm, the most abundant of all animals. Four out of five animals on Earth are nematode worms — if all solid materials except nematode worms were to be eliminated, you could still see the ghostly outline of most of it in nematode worms.

On the lawn next to the sidewalk a fire ant colony is swarming. The ants are pouring out of a mound nest, here no more than an irregular pile of dirt partly flattened by the last pass of a lawnmower. Winged queens and males are taking off on their nuptial flight, protected by angry-looking workers that run up and down the grass blades and out onto the blistering-hot concrete of the sidewalk. The species is unmistakably Solenopsis geminata, the native fire ant.