German cockroaches are believed to have originated from Africa before spreading throughout much of Asia, Europe, and eventually, the United States. However, many experts now think that these roach pests actually hail from southeast Asia. In any case, German cockroaches are now the most commonly encountered species of roach pest within homes and buildings throughout the US, Canada and Europe. The German cockroach is categorized as a “cosmopolitan” species of insect pest due to its worldwide distribution. Global trade and travel, as well as changes in urban and suburban environments have allowed German cockroaches to adapt to human dwellings to the point where they now maintain a near constant indoor presence.

The German cockroach first arrived in North America centuries ago by hitching rides on early colonial ships. Today, researchers generally agree that modern indoor heating, cooling and cooking provides German cockroaches with an ideal habitat, as these roach pests are particularly common in restaurants and food storage areas within structures. Central heating in northern regions has been providing German cockroaches with a livable and largely predator-free habitat within homes and buildings for many decades, and this species may possess a superior ability to pinpoint food by means of their olfactory organs. The German cockroaches’ appetite for a wide range of human foods also explains their ability to thrive indoors.

While the American and Oriental cockroach species are also tremendously common house pests, they do not thrive solely within indoor areas like German cockroaches. The brown-banded cockroach is the only other roach species that dwells solely indoors, but since this species arrived in America much later than the German cockroach, it is not as common within homes. Within homes, German cockroaches often congregate in dark, moist and food-rich areas, such as within bathroom wall voids and below kitchen appliances where food scraps have collected. German cockroaches can be recognized for their tan or light to dark brown exterior color and their 1.3 to 1.6 cm length. The German cockroach can be distinguished from similar looking cockroach species by the presence of two black bands just behind its head on the other side of their first pair of legs.

Have you ever encountered a congregation of cockroaches after moving appliances or furniture?