Field Guide to Venomous and Medically Important Invertebrates ...

Cockroaches
Cockroaches are not medical pests in the strictest sense, but some domestic species can
mechanically transmit bacteria and viruses to food products and food preparation surfaces. Some
people may develop allergic reactions from contacting the feces and body parts of cockroaches,
but such reactions are uncommon unless the exposure is frequent and cockroach populations are
high. Other people may experience psychological distress at the sight of cockroaches resulting
in lowered morale. However, the presence of cockroaches normally does not present a threat to
people. Of the several thousand described species of cockroaches in the world, only a few are
considered to be serious pests and they are closely associated with human habitation. All of
these nuisance species have been widely introduced throughout the world. The primary pest
cockroaches worldwide include the German cockroach (Blattella germanica), brown-banded
cockroach (Supella longipalpa), smoky brown cockroach (Periplaneta fuliginosa), Asian
cockroach (Blatella asahinae), and Oriental cockroach (Blatta orientalis). The American
cockroach (Periplaneta americana) can be a pest in the southern United States and Mexico, but
it tends to be more of an incidental entrant to homes rather than a true pest. Other cockroach
species may occasionally enter houses, but they are not considered to be significant pests.
Figure 78. Oriental cockroach (Blatta orientalis), male. Photo: University of Michigan.
Figure 79. Oriental cockroach (Blatta orientalis), female. Photo: University of Michigan.
Figure 80. German cockroach (Blattella germanica). Photo: James L. Castner.
Figure 81. Brown-banded cockroach (Supella longipalpa). Photo: Texas A&M University.
Figure 82. American cockroach (Periplaneta americana). Photo: Museums of Cape Town.
True bugs