The invasive Turkestan cockroach is displacing the oriental cockroach in the southwestern US

The Turkestan cockroach, Blatta lateralis (Walker), has become an important invasive species throughout the southwestern United States and has been reported in the southern United States. It is rapidly replacing the oriental cockroach, Blatta orientalis (L.), in urban areas of the southwestern United States as the most important peri-domestic species.

In 1978, the Turkestan cockroach was first reported at Sharpe Army Depot in Lathrope, CA, and it is now widely distributed throughout California and urban centers of the southwest. This species is widely available for purchase on the Internet by animal breeders needing live insects. They are especially popular among reptile breeders because they are easily maintained in the lab, unable to climb smooth surfaces, breed in large numbers, and easy to handle.

However, even though Turkestan cockroaches are now widespread and readily available on the Internet, there is little information on their biology. In a new article in the Journal of Economic Entomology called "Life History and Biology of the Invasive Turkestan Cockroach (Dictyoptera: Blattidae)," the authors describe its life history and they compares this information with the closely related oriental cockroach.

Two parameters that might contribute to the success of Turkestan cockroaches compared with oriental cockroaches, the authors write, are that the developmental period of the nymphs of Turkestan cockroaches are shorter, and adult female Turkestan cockroaches produce considerably more eggs than do oriental cockroaches.

They also have a more rapid life cycle than the oriental cockroach, allowing them to become adults after five molts, whereas oriental cockroaches require between 7 and 10 molts.

"It will be interesting to follow the spread of the Turkestan cockroach in the United States," the authors write. "This may be the first time that an invasive urban pest species is widely distributed via the Internet and through the sale of live insects."