What do they look like?

Cockroaches are long, flat, brown insects. Their heads point downward and have chewing mouthparts. A plate from the top of the thorax covers the head when you look down on them, so you can't actually see the head. They are very fast runners. They have long antennae, and at the end of the abdomen are two short antennae-like structures that sense air current and vibrations.

Where in the world do they live?

There are over 4,000 species of roaches spread all around the globe, and lots more still unknown to science. In Michigan there are only a couple of dozen species, and about half of them are invaders that came along with European settlers.

What kind of habitat do they need?

Most cockroach species live in dead leaves and soil on the ground in forests. A few well-known species have adjusted to living with people in houses and other buildings.

How do they grow?

Cockroaches have incomplete metamorphosis. Immature roaches look pretty much like adult roaches, except they don't have wings yet. As they grow the molt (shed their whole skin at once) several times. After the last molt, they roach has wings and can reproduce. It stops growing and molting at that point.

How do they reproduce?

Female roaches produce dozens of offspring several times in their lives. Most species produce an egg case with up 40 eggs. A few species keep the eggs in their abdomen until they hatch, and some actually give birth to live young.

Most roach species, including the ones that live in houses, don't have any parental care. In some of the woodland species females guard over their young for a short time after they hatch. A few species live together in burrows in dead wood.

How long do they live?

Lifespans vary with species. Some can live for two years.

How do they behave?

Most roaches are solitary nocturnal scavengers. Those living in buildings prefer locations that are warm and or damp. A few wild species are more social and live in groups. These species can eat wood (they have special microbes in their guts like termites) and live in decaying logs.

How do they communicate with each other?

Most roach species use touch and taste/smell as primary senses, but some also communicate with vibrations or other sounds. They hiss, or rub their wings together. The sound startles predators and gives roach a chance to escape, and is sometimes used to attract the opposite sex.

What do they eat?

Roaches are scavenging omnivores, they'll eat just about any organic matter they can find. They don't have a powerful bite, so they don't usually eat living animals.

What eats them and how do they avoid being eaten?

Most roach species don't have any special defenses, they just hide, only come out in the dark, and run fast. A few species have chemical defenses.

What roles do they have in the ecosystem?

In wild habitats, roaches help breakdown dead plants and animal waste.

Do they cause problems?

Cockroaches are the biggest household pest problem in most cities and towns. They spread bacteria that can make people sick.

How do they interact with us?

The great majority of roach species never bother people. They live outside, and are a harmless part of foodwebs.

Are they endangered?

No roach species are considered endangered.

Contributors

George Hammond (author), Animal Diversity Web Staff.