When cockroaches reproduce, they create many tiny egg capsules called oothecas. Each of these ootheca contains up to 30 to 40 eggs. A female cockroach can produce up to eight ootheca during her lifetime. As a result, the cockroach population grows by 30 times every hundred days.
German cockroaches are among the fastest reproducing species of roaches. Female German cockroaches can lay between four and eight egg capsules per lifetime, each containing between thirty to forty eggs. The eggs hatch within twenty to thirty days, depending on temperature. After that, German roach nymphs can mature into adulthood in forty to 125 days.
The reproduction rate of cockroaches depends on the amount of sperm and eggs produced by each sex. Female cockroaches release pheromones that attract the male. The male cockroach then fights for the available females. The faster they reproduce, the more likely they are to produce larger infestations.
The German cockroach is one of the fastest-reproducing species, producing between eight and one hundred thousand eggs per year. While most roach species can produce several roach generations a year, the German cockroach has the highest rate of reproduction. In a year, a single female can produce hundreds of eggs.
Another cockroach that reproduces quickly is the Oriental cockroach, which produces a new brood every two months. They thrive in cooler temperatures and are found in basements, crawl spaces, and outdoor trash heaps. Oriental cockroaches are known to carry a number of diseases. Their eggs have been linked to gastroenteritis in humans.