The German cockroach likely originated in limestone caves in Borneo, a tropical island in the South China Sea. Related Blattella species still live there. The caves are massive and have a consistent climate with high temperatures and humidity — in fact, the climate kept peppercorns dry and the cave offered security from pirates. After a sale, baskets of dry peppercorns would be loaded onto schooners that would ride trade winds to the port city of Malacca, Malaysia. The warehouses there were a stopover in the spice trade.
Caves to Kitchens
The consistent temperature and humidity of the Borneo cave system and the limited number of natural predators would provide B. germanica an ideal habitat for success. Fast forward to kitchens and bathrooms in apartments and consider the seasonal abundance of adults and nymphs. It reflects a habitat that has little variation in the temperature and humidity with little variation throughout the year. B. germanica got a little spoiled evolving in the cave habitat — consequently, it does not live or survive outdoors and prefers indoor harborages.
Malacca to Manhattan
The cockroaches in the baskets could easily endure the 13-day sail to India and the 20-day sail or overland trek to Venice — the spice capital of Europe in the 1600 and 1700s. German cockroach females can live for 12 days without food or water, and 42 days on just water. It seems B. germanica would have been well prepared for any storage or sailing environment.
Once this small cockroach became established in the spice storage buildings in Europe, a Danish entomologist found it. After he gave it a brief mention and a name (B. livida), he sent a few specimens off to a colleague in Sweden. In 1767, Carl Linnaeus changed the name to “Germanica” and we have called it the German cockroach ever since.
The German cockroach most likely took a direct route to the U.S. without a stopover in Europe. In 1796, Captain Jonathan Carnes left Salem, Massachusetts, and sailed to Borneo to buy Sarawak pepper. He returned with 140,000 pounds but stopped off at the South Street Pier in Manhattan to sell some before heading to Salem. Cockroaches that made the trip easily infested the port facilities in New York City. From there, they caught rides on the pepper sacks to markets in the city.
Croton Bug to Chlordane
In 1842, the Croton Reservoir brought indoor plumbing to NYC apartments. That six-legged Borneo expatriate now had harborage, food and water in every apartment it crawled into. German cockroach populations and pest status took off. Everywhere plumbing went, so did B. germanica. By the 1850s, it got the nickname “Croton Bug.” After water pipes came the cockroaches, and the bugs never left.
By the 1900s, the German cockroach was becoming a widespread pest. After indoor plumbing gave it a foothold (tarsal hold?) indoors, the electric refrigerator in the 1920s/1930s sealed the deal. The drip pan at floor level provided a constant supply of water and the electric motor a cave-like temperature. The trip from Borneo to kitchens was complete.
The German cockroach owes its success to a skill set developed in Borneo caves that was put to use on the trip with Sarawak peppercorns to kitchens around the world. Professional pest control owes its success to the skill set of the chemists developing insecticides, and to the foresight of Bill Brehm and George Gilmore for designing a sprayer to apply them.