CARPENTER ANTS

“One day when I went out to my wood-pile,” wrote Henry David Thoreau in his classic Walden; or, Life in the Woods, “I observed two large ants, the one red, the other much larger, nearly half an inch long, and black, fiercely contending with one another. Having once got hold they never let go, but struggled and wrestled and rolled on the chips incessantly.” Waging war is just one of the habits that ants share with humans: Many species live in large, well-organized societies, and others take slaves, herd aphids like cattle, and raise fungi for food in underground farms. Ants are also, according to biologist Edward O. Wilson, the premier turners of soil in the world, the chief predators of other insects, and the principal scavengers of small dead animals—all activities that ultimately benefit humans. Camponotus floridanus, the Florida carpenter ants fighting here—one has locked its mandibles on the other’s antenna—share something else with humans: their homes. Living in large tightly knit communities within nests hollowed out in wood softened by moisture or fungi, these ants are fond of sweet fluids, and during the night they often scavenge for sugary juice around soda machines. Their nests are common in attics, closets, and fuse boxes, to which they gain access by following chemical trails along wires or branches that form bridges to safe spots under the roof.


BEDBUG

For much of human history the bedbug has been hard to dislodge.

“It is said to have its origin in warm blood, and has an extravagant fondness for humans,” wrote the 14th-century Egyptian theologian Kamal ad-Din ad-Damiri. He was mistaken about its origins: The common bedbug, Cimex lectularius, emerges by night from the walls of houses or bedding to quaff the blood the insect needs to molt from nymph to adult. It does, however, appear to have been our companion since we first took to dwelling in caves: At least 12 species of blood-sucking Cimex bugs are parasites of bats, and many others feed on cave-nesting birds. Once driven away by DDT, the bedbug seems to be making a comeback, fueled by the trade in old flea-market furniture. Though it does not transmit disease, excessive biting can cause anemia in infants. The ancients inexplicably awarded them medicinal powers. The Roman Pliny the Elder, for example, recommended them for snakebites. “Seven bed bugs mingled with water were a dose for a man, while four were sufficient for children,” writes Glenn Herrick in his 1914 book Insects Injurious to the Household and Annoying to Man, “The smell of them will [also] relieve ‘hysterical suffocation.’”