FAMILIES OF BLATTODEA (COCKROACHES) OF BRITISH COLUMBIA
R. A. Cannings and G. G. E. Scudder
Copyright © 2005 - All rights reserved
Extracted from the forthcoming publication The Insect Families of British Columbia
Key to families of Blattodea
1. Middle and hind femora armed ventrally on both margins with rows of strong subequal spines; males with styles simple, slender and usually symmetrical; females with sternum VII bivalvular................................................ Blattidae
- Middle and hind femora unarmed ventrally or with only weak unequal or distally arranged spines; males with styles asymmetrical or absent; females with sternum VII not bivalvular ..........................................................................2
2. Antennae longer than half length of body; middle and hind femora usually with ventral spines in two unequal rows; small to medium sized species......................................................................................... Blattellidae
- Antennae usually less than half length of body; middle and hind femora ventrally with only a few weak spines or none at all; moderate to very large species ................................................................................................Nauphoetidae
Description of Families
Family Blattidae (blattid cockroaches)
Most species are red-brown to black, often with contrasting pale and dark marks on the pronotum. The wings may be fully developed or reduced in length in both sexes, but in females they are usually shorter than in males. There are strong spines on the underside of the middle and hind femora.
The Blattidae is a large family, with about 650 species worldwide. A few of these many species are pests, and are among our most unwelcome companions. The family includes the largest cockroaches (to 35 mm long) established in Canada; all our species are pests and live in homes, greenhouses, warehouses and other buildings. Three species are established in B.C., one in Blatta and two in Periplaneta. In addition, P. fuliginosa (A.-Serville) has been reported, but populations have not survived.
Blatta orientalis Linnaeus, the Oriental Cockroach, probably originated in the Middle East and spread through human activity to western Europe from where it invaded North America. The first B.C. record is from a Victoria Bakery in 1930. It is 25 mm long and dark brown. Neither sex can fly; the female’s wings are small stubs, but the male’s wings cover 2/3 of the abdomen and are squared off at the ends. It lives gregariously in dark, warm, damp places where, in the best conditions, it may produce a generation every six months. A female may produce as many as six oothecae during its life; these contain up to 18 eggs and are cemented in some dark cavity.
Periplaneta americana (Linnaeus), the American Cockroach, said by some to be a native of tropical and subtropical America, is evidently originally from West Africa and probably arrived in southwestern North America via the Orient. In B.C. it was first recorded on the Vancouver waterfront in 1922. It is our largest species, up to 40 mm long and red-brown; the pronotum is yellow-brown, marked with a pair of large indistinct chestnut-brown patches. Both sexes are winged. Smaller (to about 30 mm), the Australian Cockroach, P. australasiae (Fabricius) has a red-brown to orange pronotum bearing two large, well-defined, usually joined, black blotches. It probably originated in eastern Africa, arriving first in California from Asia. It prefers warmer temperatures than P. americana. Both species mature in about a year.
Family Blattellidae (blattellid cockroaches)
The Blatellidae is the largest family of cockroaches, containing about half the species in the world. Canada’s only native cockroaches, three species of Parcoblatta (wood cockroaches) in the forests of southeastern Canada, belong to this family. Two species in two genera are introduced in B.C.
Blatella germanica (Linnaeus), the so-called German Cockroach, is hardly German at all; it probably came originally from northeastern Africa, traveled to Asia and Europe, then came to Canada across the Pacific Ocean from the Orient or via Europe to eastern North America. It is the most abundant and firmly established cockroach in B.C.; by the 1920s, it occurred in most cities and towns in the southern half of the province. It likes particularly warm buildings such as bakeries, restaurants, apartment buildings and hotels, but is able to live outside in warm refuse dumps, at least in the mild climate of the south coast. B. germanica is yellow-brown, 10-13 mm long, and the pronotum is pale with two distinct dark, longitudinal stripes. Both sexes are winged; the forewings are narrow and extend past the end of the abdomen. The female extrudes an ootheca containing 30 or 40 eggs, but can carry the capsule around for a month or more before depositing it. at 30ºC, nymphs take as little as five to six weeks to reach adulthood.
Supella longipalpa (Fabricius), the Brown-banded Cockroach, probably arrived in Canada from Africa via the Caribbean islands and the southeastern United States. It is 10-12 mm long and both sexes have pale brown wings. The male’s forewings extend past the end of the abdomen and are marked with two dark patches in the basal half. The female’s wings are shorter, barely reaching the tip of the abdomen; the dark blotches reach into the apical half. Although in B.C. it has been recorded only in the Lower Mainland, it tends to dominate and replace other cockroach species where it occurs, and may spread farther afield in the province. An undetermined species in the genus Neoblattella, related to Supella, has been recorded in B.C., but never became established.
Family Nauphoetidae (wandering cockroaches)
The wandering cockroaches are often included in the family Blaberidae. Pycnoscelis surinamensis (Linnaeus), the Surinam Cockroach, is the sole member of this family established in B.C. It was first found in a Vancouver office building in 1986, apparently introduced on house plants from the United States. In other parts of North America it is a pest in greenhouses. The Surinam Cockroach is not from South America at all, but is an Indomalayan species that has spread around the world. The species is about 20 mm long; the pronotum is uniformly dark except for a pale front margin and the antennae are relatively short, less than half the body length. The wings are pale brown and well developed. The ootheca produced by the female is retained in the brood pouch until the eggs hatch. Two other species in the family, Panchlora nivea (Linnaeus) and P. latipennis (Saussure and Zehntner) have been reported in the province, but are not established.