Art Appel, Marla Tanley, and T'ai Roulston

Just what the citizens of Alabama need, another cockroach! But relax, it's not likely to become a pest of homes and structures.

The pale-bordered cockroach, Pseudomops septentrionalis Hebard, was first found in Alabama in May 1996. This small (5/8-inch long), strikingly colored species was identified from collections made at three different locations in Lee County, including the Auburn University Donald Davis Arboretum. This species is presumed to be established in Alabama because it has been collected every year since 1996 and has been reported from additional sites each year. The pale-bordered cockroach has been reported from Arkansas, Louisiana, Oklahoma, and Texas, as well as from Costa Rica and northern Mexico. To date, this cockroach has not been reported from any other southern state. Cockroaches are poor fliers and unable to cross large bodies of water. This is the first known case of a native North American cockroach spreading in the United States by means of human transport.

To study the biology of this species and learn more about the potential this new Alabama resident has as a pest, laboratory colonies were established by collecting cockroaches and housing them in one-gallon jars stocked with dry dog food and water. Sticks and dried leaves were added to each jar to provide harborage and to simulate their natural surroundings. Colonies were kept at 77^oC and exposed to a 12-hour-dark:12-hour-light photoperiod.

Photo 2. Egg case of pale-bordered cockroach.

Results of this study showed that adult females can produce up to 16 egg cases (oothecae) during their more than four-month life span. Egg cases are 9/32 inch long, weigh 0.00051 ounce, and take 45 days to hatch. Approximately 23 offspring emerge from each egg case; there are three or four generations per year..

Adult pale-bordered cockroaches have been observed outdoors on foliage and in ground litter. Individuals have been found perched 1.6 to 6.6 feet from the ground on various herbs and shrubs, including privet. Unlike many other insects, pale-bordered cockroaches are not attracted to black lights. Black lights are often used to collect insects at night. Most insects are attracted to them. The pale-bordered cockroach probably would not fly into a home at night when a porch light is on.

Compared with other cockroach species, the pale-bordered cockroach is relatively sensitive to desiccation, which helps explain why its distribution pattern is in relatively humid locations. In nature, egg cases are laid on moist soil or under rocks. In the laboratory, egg cases must be placed on wetted pieces of sponge so they can absorb enough water to hatch. Male pale-bordered cockroaches lose water at a relatively high rate, similar to tropical cockroaches. Household cockroaches, such as the German and brownbanded, have relatively low rates of water loss, which allows them to tolerate dry conditions within air conditioned and heated homes. This need for water will likely keep the pale-bordered cockroach from becoming a household pest. Instead, the pale-bordered cockroach should be considered an interesting new species that could provide food for other animals in our environment.