German cockroaches are thigmotactic, meaning they prefer confined spaces, and they are small compared to other pest species, so they can hide within small cracks and crevices that are easy to overlook. In color it varies from tan to almost black, and it has two dark, roughly parallel, streaks on the pronotum running from behind the head to the base of the wings, although it has wings, it can barely fly, although it may glide when disturbed.
In cold climates, they occur only near human dwellings, because they cannot survive severe cold. However, though they would soon die in the outdoors on their own.
German cockroaches are omnivorous scavengers. They are attracted particularly to meats, starches, sugars, and fatty foods. Where a shortage of foodstuff exists, they may eat household items such as soap, glue, and toothpaste. In famine conditions, they turn cannibalistic, chewing at each other's wings and legs.
The German cockroach reproduces faster than any other residential cockroach, growing from egg to reproductive adult in roughly 50 – 60 days.
The oriental cockroach, commonly referred to as “water bugs or black beetle”, is a large species of cockroach It is dark brown or black in color and has a glossy body.
Oriental cockroaches tend to travel somewhat more slowly than other species. They are often called “water bugs” since they prefer dark, moist places. They can often be found around decaying organic matter, and in sewers, drains, damp basements, porches, and other damp locations. They can be found outside in bushes, under leaf ground cover, under mulch, and around other damp places outdoors.
To thrive, cockroaches need a place to hide. They prefer warm places and a relatively high humidity; they also need a source of food/liquid. The optimum temperature for oriental cockroaches is between 68 and 84 °F. Female oriental cockroaches have reduced fore wings and males have longer fore wings. Cockroaches are mainly nocturnal. Oriental cockroaches can be elusive in that a casual inspection of an infested dwelling during the day may show no signs of roach activity.
The American cockroach has the largest body size; molts 6–14 times before metamorphosis; and has the longest lifecycle, up to about 700 days. They are reddish brown and have a yellowish margin on the pronotum, the body region behind the head. Immature cockroaches resemble adults except they are wingless.
American cockroaches are omnivorous and opportunistic feeders that eat materials such as cheese, beer, tea, leather, bakery products, starch in book bindings, manuscripts, glue, hair, flakes of dried skin, dead animals, plant materials, soiled clothing, and glossy paper with starch sizing. They are particularly fond of fermenting foods. They have also been observed to feed upon dead or wounded cockroaches of their own or other species.
American cockroaches generally live in moist areas but can survive in dry areas if they have access to water. They prefer high temperatures around 84 °F and do not tolerate low temperatures. These cockroaches are common in basements, crawl spaces, cracks and crevices of porches, foundations, and walkways adjacent to buildings. In residential areas outside the tropics, these cockroaches live in basements and sewers, and may move outdoors into yards during warm weather.