Why is this cockroach taking over America?

Meet the Turkestan cockroach: a creepy-crawly pest that has spread through the southwestern United States and is poised to invade the rest of the country as well. It thrives in cable boxes, pavement cracks, manure piles, sewers, and manholes.

Now scientists have found out why this species may have flourished. It develops faster than its main competitor, the oriental cockroach, and produces more eggs.

A native of the Middle East, the Turkestan cockroach probably came to America via military shipments. People first spotted the species at an army depot in California in 1978. From there, reports of the bug popped up in Los Angeles, Arizona, and Georgia. Now, reptile breeders can buy Turkestan cockroaches online, which “will likely spread them throughout the rest of the United States,” the study authors predict in the Journal of Economic Entomology.

To find out more about the species, the researchers studied Turkestan cockroaches that had been collected by a pest control company from an elementary school in Fresno, California. The team raised the critters in glass jars containing dog chow. The cockroaches were allowed to mate, and the researchers observed the offspring’s growth.

Each female produced up to 25 egg cases, and the cockroaches took an average of 222 to 224 days to develop. In contrast, the development times reported for oriental cockroaches range from 315 to 533 days, and their females produce only 5 to 10 egg cases.

People can help hold back the invasion by not leaving pet food outdoors, the authors say. But since the cockroaches can be ordered online, they will almost certainly spread. “This may be the first time that an invasive urban pest species is widely distributed via the Internet and sales of live insects,” the team writes. Roberta Kwok | 10 December 2013

Source: Kim, T. and M.K. Rust. 2013. Life history and biology of the invasive Turkestan cockroach. Journal of Economic Entomology doi: 10.1603/ec13052.

Image © D. Kucharski K. Kucharska | Shutterstock