Exotic cockroaches adapt … and succeed


January 20, 2014

In the Journal of Economic Entomology entomologists from Rutgers University recently reported an exotic species of cockroach was found in New York. Periplaneta japonica, the Japanese cockroach (sometimes referred to as the Wamato cockroach), is a native of Japan, but it’s also found in China, Korea and Russia. P. japonica was first found by a pest management professional (PMP) on the High Line, an aerial park constructed in Manhattan, last year. Although exactly how this cockroach species was introduced to North America remains a mystery, researchers have hypothesized people might have stowed it away on plant materials or in soil that was used to construct the aerial park where the cockroach was first discovered.

How far and to what extent P. japonica will spread remains to be seen. But its introduction reminds us all three major pest cockroach species encountered throughout the United States are all invasive species. The American cockroach (P. americana), Oriental cockroach (Blatta orientalis) and German cockroach (Blattella germanica) are exotic species that have established themselves throughout the world. Interestingly, all three of these species are geographical misnomers — each is thought to have originated in Africa, not the places indicated in their common names. These cosmopolitan pests were spread throughout the world on ships centuries ago, with some of the first reports in North America originating in the early 17th century.

Each of these pest cockroaches has the ability to adapt readily to life in environments engineered around humans. German, American and Oriental cockroaches are well suited to living inside structures, as well as in the infrastructure that connects the urban and suburban environments. For example, the small size of German cockroach nymphs that emerge from an ootheca enable them to escape predation from larger nymphs and adults by hiding inside the tiniest of cracks and crevices in kitchen cabinets. The sheer number of nymphs emerging from oothecae ensures populations grow rapidly. Also, the length of time a gravid female German cockroach carries an ootheca before depositing it helps secure the safety of the developing eggs by protecting them from predators.

Other, more recent exotic cockroach invaders are established, too. For example, in the Southwestern U.S., the Turkestan cockroach (Blatta lateralis) has quickly reached pest status following its introduction in 1978. It has outcompeted the Oriental cockroach in areas of its range to become the most important peridomestic cockroach species threatening structures today.
P. japonica has received a fair amount of attention from the press thanks to its ability to survive subfreezing winter temperatures. It’s well suited for survival indoors and out, even in the cooler regions of the United States. Based on reports from Asia, this cockroach has a flexible lifecycle that can be extended into harsh winters in colder climates through a nymphal diapause phase. Alternatively, the lifecycle can be quickened in warmer climates.

We’ve seen introductions of adaptable, exotic cockroaches in the past. What will the future hold for this one? pmp

You can reach Dr. Fredericks, technical director for the National Pest Management Association (NPMA), at jfredericks@pestworld.org.

Leave A Comment

Comments are closed.