Invasive Cockroach Spreading Throughout California, Internet Sales Continue

File this one under "what are they thinking?" An invasive cockroach species first noted in California in 1978 is now well established throughout the cities and towns of the southwestern U.S., and though little is known about its biology or its effect on other wildlife, you can still buy it online.

First seen in California 35 years ago in the town of Lathrop, the Turkestan cockroach (Blatta lateralis) is now rapidly displacing its cousin the oriental cockroach, Blatta orientalis in many parts of California as the cockroach most commonly found in and near human habitations. That may be because Turkestan cockroaches breed faster and lay more eggs than do oriental cockroaches, say entomologists.

It's not likely that anyone will shed a tear of sympathy for displaced oriental cockroaches. But so little is known about the Turkestan cockroaches' biology that the effect the invaders might have on native wildlife is pretty much a mystery. But that doesn't mean you can't order as many of the bugs as you want on the Internet, for delivery across state lines.

Turkestan cockroaches are popular with reptile owners as a source of food for their insect-eating pets. Two inches long and relatively easy to raise, the cockroaches are reluctant to climb vertical surfaces and can therefore be kept more or less confined in a large plywood box, or similar container.

As is the case with other insects, Turkestan cockroaches molt -- that is, shedding its exoskeleton revealing a new mature stage -- several times throughout the course of their lives. Unlike their oriental cockroach cousins, however, Turkestans become reproductively mature adults after five molts. (Oriental cockroaches require between seven and ten molts before they can start reproducing.)

According to the Integrated Pest Management website maintained by the University of California at Davis, Turkestan cockroaches seem to prefer outdoor habitats in proximity to humans. Where they exist in California, Turkestan roaches are commonly found in pavement cracks, buried utility boxes, compost piles, and among debris. (They seem to enjoy hanging out in the potting soil around the roots of outdoor potted plants, something that avid container gardeners will want to keep in mind when bringing plants indoors during extremes of temperature.)

And they're pretty easy to find on the internet as well. This New York-based breeder, for example, ships the roaches to all 50 states, save Florida, and describes the species as "taking the feeder roach market by storm."

It's unlikely that reptile fans are responsible for the roach's presence in California. In an interview with the Los Angeles TImes, U.C. Riverside entomologist Michael Rust -- who has a paper on the species in the most recent issue of the Journal of Economic Entomology -- points out that the Turkestan cockroach's 1978 debut in California was at Fort Sharpe, appearing soon after at other military bases such Fort Bliss in Texas. As the roach is native to the Middle East and Central Asia, the potential for military personnel to have brought the roach home with them seems clear.

Regardless of how the roach got here, it's unusual for an invasive species to be sold so readily and freely online. "It will be interesting to follow the spread of the Turkestan cockroach in the United States," Rust and his co-authors said in a press statement. "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."