Introduction:The Brown cockroach is often mistaken for the American cockroach which it closely resembles in appearance and habits. It is primarily tropical in distribution and probably of tropical African origin. Although found mainly in the southern United States westward through Texas, it occurs as far north as Philadelphia, Pennsylvania, and Columbus, Ohio. It has been introduced into California several times but apparently is not established.
Adults about 1 1/4 - 1 1/2" (33-38 mm) long. Color dark reddish brown except for an irregular and sometimes faint yellowish brown to brown submarginal bandlareas near edge of pronotal shield. Last segment of carcus short and triangular, length less than twice width. Wings fully developed with male's barely extending beyond tip of abdomen; tend to glide rather than fly.
Nymphal early instars brown to dark brown; lst instar with abdominal lateral margins much darker except basal 2 segments with faint lateral spots; instars 1-4 with mesothorax pale/white but anterior and posterior margins dark; instars 1-5 with 2nd abdominal segment having pale lateral areas; antennas with basal 4th pale in instars 1-4 and with 4-5 apical segments white in instars 1-2 or tips pale in instars 3-4. Later instars reddish brown with lateral and posterior margins of segments darker and paleness on mesothorax, 2nd abdominal segment, and antennae fading out. Cerci broadly rounded laterally, length about 4 times width with widest segments about 3 times as wide as long. Ootheca or egg capsule brownish when deposited, then turns black; about 1/2" long (average 11.7 mm, range 7-13.5 or average 13.5 mm, range 12-16), with length more than twice width; subdivisional furrows extend entire width; keel not extending downward to beyond 1/4 of width of end with terminal point; and with 12-14 eggs on each side.
- Similar Groups
- American cockroach (Periplaneta americans) with last segment of cercus at least 2 times longer than wide.
- Australian cockroach (P. australasiae) has front wings with outside margin at bass pale yellow.
- Smokybrown cockroach (P. fuliginosa) uniformly brownish black.
- Other cockroaches are either smaller or larger, lack characteristic pale markings or characteristic terminal cercus segment, and/or are not associated with structures.
The female deposits her ootheca within a day after it is formed. It is securely glued with a mouth secretion to a suitable surface in the open near the ceiling, usually on plaster or concrete. The female often covers her ootheca with plaster which she has removed from the surrounding area, thus making the ootheca blend in with the plaster background. The female will produce up to 32 oothecae with each containing an average of 24 (range 21-28) eggs.
Developmental time (egg to adult) is strongly influenced by temperature, but at room temperature it averages about 224-340 days. This cockroach can reproduce parthenogenetically (without fertilization by a male) but the hatch rate is 9% and only about 1/3 of these reach maturity, all being females. Adults live about 244 days (range 64-392) but some have been kept alive for more than 20 months.
The brown cockroach prefers hot and humid areas and is usually found in the same areas/sites one would expect to find American cockroaches. Such places include food-storage areas, basements, crawl spaces, grocery stores, and sewers. In the South, they survive quite well outdoors and are found in leaf litter, ground cover, in association with trees, especially palm trees, and around dumps.
They enter structures by being brought in, through cracks or holes in exterior walls, and through sewers. The brown cockroach normally feeds on plant materials.