Life Cycle of a Cockroach

Cockroaches are the most common insect pest in North America.

Cockroach species have been on the planet for a very long time. Their evolutionary success hinges on their simple biology. Cockroaches are scavengers and feed on a wide variety of organic matter. The cockroach reproductive cycle is fast, allowing large populations to develop quickly when resources are abundant.

Egg

The cockroach life cycle starts with an egg. After mating, a females creates an egg case with six to 40 eggs. Females often carry around the egg sac, called an ootheca, for safekeeping, depositing it in a secure location just before the eggs are ready to hatch.

Nymph

Nymphs, newly hatched cockroaches, are pale and soft but develop a hard exoskeleton shortly after hatching, when they molt. Each phase between molting is called an instar. The number of instars before a nymph reaches its adult phase varies by species. Some species develop into adults in several weeks; others do not mature until after several years of molting.

Adult

Once a cockroach reaches maturity, it never molts again. Many species develop a pair of wings with their final molt; often, the presence of wings is the only identifiable difference between nymphs and adults. The length of an adult cockroach's life depends on its diet and environmental conditions; under ideal conditions, cockroaches may live for two years.

References

• University of California Statewide Integrated Pest Management Program: Pests of Homes, Structures, People, and Pets: Cockroaches
• University of Rhode Island Factsheet: Cockroaches
• University of Maine Cooperative Extension: Cockroaches
• Orkin: American Cockroach Life Cycle
• University of Minnesota Extension: Cockroaches

Resources

• University of Kentucky, College of Agriculture: Cockroach Elimination