Oriental Cockroach (Blatta orientalis)

Description and Identification

These cockroaches display sexual dimorphism in size and physical features. The males appear larger, with a length of 0.71 to 1.14 inches (18 to 29 mm). The females are smaller, measuring 0.79 to 1.06 inches. The overall coloration of both sexes varies from black to brown; their bodies also have a glossy texture. This has also resulted in their other alternate name, black beetle or black cockroach. 

One could also easily distinguish a male from a female through their wings. The males have a narrow body and long wings covering about 3/4th of their abdomen. The females don’t have wings but pads that give the impression of tiny wings. The male roaches have a slender, narrow bodies than their female counterparts, which appear wider, resembling the Florida woods cockroach. 

Distribution: Distributed globally, occupying parts of Europe, Australia, North America, and South America

Habitat: Outdoors – Under bushes, leaves, firewood, debris, and stones, as well as drains and sewers; Indoors – In garages, porches, damp basements, under sinks, near garbage cans, in toilets

Do They Bite/Sting: Yes; they can bite, but do so rarely to people

Lifespan: 35 – 90 days  

Predators: Spiders, beetles

Behavior and Characteristics

Diet

These voracious eaters feed on anything and everything, with garbage and decaying organic matter on top of the list.

Flight

The males have wings. However, the females do not, yet both male and female oriental cockroaches cannot fly.

Life Cycle

1. Egg Stage

The eggs, 0.39 – 0.47 inches long, are housed in the compartments of the egg cases or ootheca, 16-18 of them together. The females carry the egg capsules for a duration as short as twelve hours or as long as five days. She then puts it in a warm place where food is readily available. These eggs, too, attain the similar blackish-brown coloration seen in the adult cockroaches in the final stage. However, before turning blackish-brown, they undergo two color changes, first appearing yellowish-white and then reddish.

2. Nymph Stage

The baby cockroaches don’t have wings, as seen in their adult counterparts. They go through about seven to ten molts before maturing into adult oriental cockroaches. The nymphal stage lasts for anywhere between 24 and 130 weeks.

3. Adult Stage

The development cycle of the oriental cockroach is seasonal. One could mainly spot adults in the late spring – early summer phase. However, their numbers eventually lessen in the latter half of summer or early fall.

Comparison with Similar Species

Are Oriental Cockroaches Dangerous

Since these cockroaches mostly remain in or near water sources, they inhabit all those places contaminated with bacteria and viruses. They carry these germs using their legs, dropping them on dishes, foods, countertops, and everywhere else they infest. When one ingests the infected food, they could contract dysentery from food poisoning alongside allergic reactions.

Getting Rid of Them

One of the signs of their infestation is the foul and musty smell emitted by these cockroaches to communicate and send out signals to their fellow roaches. The reddish or dark brown egg capsules around your home also indicate their presence. Keeping your house clean is a mandate to get rid of them or avoid their infestation altogether. Seal cracks or crevices in the wall or other areas, as that is one of the most favorable places through which they may gain entry into your home. Keep the indoors and outdoors clean and dry, as wet places are their most preferred habitat.

Spraying insecticides is an option but not a permanent solution as though it could help kill roaches, yet new nymphs would hatch in around two months. In the case of increased infestation, where controlling their population seems a mammoth task, calling for a professional exterminator would be feasible.