Aliens in the Backyard: Plant and Animal Imports into America

House Pests: Some of Those Who Share Your Quarters

143 House Pests Some of Those Who Share Your Quarters House pests, like the houses they plague, are almost all imports to America. Few, if any, are accurately named either popularly or scientifically as to country of origin, although the warm, humid environments they like point to a tropical birthplace for these cosmopolitan creatures. Not that country of origin has stopped us from slurring other nations; the misnamed American cockroach (Periplaneta americana), German cockroach (Blattella germanica), and Oriental cockroach (Blatta orientalis) probably came from Africa. Even professionals get emotional over cockroaches: “One of the filthiest of all insects is the cockroach , which secretes a foul liquid from its scent glands, an obnoxious saliva from its mouth, and leaves its excreta wherever it travels.”1 The one-and-a-half-inch-long American cockroach, also called the water bug, flying water bug, and palmetto bug, arrived here aboard early explorers’ ships. Many entomologists think it was probably this cockroach that John Smith described in 1624 as plaguing Virginian colonists, “A certaine India bug, called by the Spaniards a cacarootch, the which creeping into chests they eat and defile with their ill-sented dung,” since its fecal droppings are among the largest and most offensive of our cockroaches’. Happiest in warm, damp, dark places, such as your kitchen cabinets and basement, the American cockroach also throngs in unimaginable numbers in our city sewers, which, in addition to heating ducts and tunnels, provide artificially tropical conditions in the north. Down South, where it can live outdoors, Periplaneta americana is called the palmetto bug and is so pervasive that some entomologists think it might, in fact, be native—although most think neither this species nor the other forty-six genera found in America are indigenous. Cockroaches are seldom found indoors except after heavy rains or during migration—when thousands can infest your yard and house, over five thousand having been trapped in a single sewer manhole . It is our largest and fastest roach, and even if you don’t see it, you’re likely to notice the cast skins and large fecal droppings.2 144 Aliens in the Backyard German cockroaches and an Oriental cockroach. John S. Kingsley, ed., The Riverside Natural History (Boston, 1888). Like other cockroaches, the American has three life stages: egg, nymph, and adult. Adult females lay one egg case, or ootheca, a month for nearly a year, each case containing about sixteen eggs. Wingless, immature nymphs hatch from the cases in six to eight weeks, and take from six months to a year to mature, shedding their skins as many as fourteen times and gradually growing ever-longer wings. A final skin shedding results in an adult, which can live another year. Newly molted cockroaches are white, giving rise to fascinating, but erroneous, stories about colonies of albino cockroaches, but their color gradually darkens. The American cockroach eats almost anything organic, although it has a penchant for sweets and, according to some, alcohol—half-empty beer bottles often containing one or more blissfully drowned cockroaches. Bottles coated with sweet residue or filled with a sweet liquid at the bottom make effective roach traps; commercial versions were manufactured during the Victorian era, and homemade traps are still used in poorer countries and by enterprising, wouldbe scientists following the cockroach-collecting suggestion on the popular kid’s science program Newton’s Apple.3 Primarily an aesthetic and social blight, the American cockroach can also spread disease, living in sewers but happily penetrating our houses. Cockroaches can carry fifty different human pathogens, including bacteria, viruses, fungi, protozoa, and worms, and spread diseases such as pneumonia, salmonella, and typhoid.4 While several wasps that lay their eggs in American cockroach ootheca have been discovered, with the young feeding on the cockroach eggs as they develop, most cockroach control in America relies on preventing cockroachs from entering our buildings, or poisoning them once they gain entry. Up north House Pests 145 their tender, tropical nature can be used against them; at least one major university controls their populations by turning the heat off during winter vacation. In sheer numbers, however, the German cockroach (Blattella germanica) is our worst cockroach pest. Found worldwide, the German cockroach’s spread seems limited solely by colder temperatures. Central heating, which became widespread in New York City at the same time the Croton Reservoir was opened, in 1842, led not only to apartment and...