Attracted males approach females and flap their wings to denote interest. Reproduction commences when a male cockroach backs into a female cockroach, depositing sperm. After fertilization, a female American cockroach produces an egg case known as an ootheca. The female carries the ootheca on her abdomen for a short time, usually a day or two. After that, she deposits it in a warm humid location. The life span of the American cockroach ranges from one to 1. As with many animals, cockroach reproduction relies on eggs from a female and sperm from a male.
Usually, the female releases pheromones to attract a male, and in some species, males fight over available females. But exactly what happens after the male deposits his sperm into the female varies from species to species.
Most roaches are oviparous -- their young grow in eggs outside of the mother's body. In these species, the mother roach carries her eggs around in a sac called an ootheca , which is attached to her abdomen. The number of eggs in each ootheca varies from species to species. Many female roaches drop or hide their ootheca shortly before the eggs are ready to hatch. Others continue to carry the hatching eggs and care for their young after they are born.
But regardless of how long the mother and her eggs stay together, the ootheca has to stay moist in order for the eggs to develop. Other roaches are ovoviviparous. Rather than growing in an ootheca outside of the mother's body, the roaches grow in an ootheca inside the mother's body. In a few species, the eggs grow inside the mother's uterus without being surrounded by an ootheca. The developing roaches inside feed on the eggs' yolks, just as they would if the eggs were outside the body.
One species is viviparous -- its young develop in fluid in the mother's uterus the way most mammals do. Ovoviviparous and viviparous species give birth to live young. Cockroach nymphs hatching together would have safety in numbers, which might counteract the disadvantage that they hatch at lower rates than offspring produced by sexual reproduction.
This may be a very primitive example of female cooperation, the researchers added. Male roaches housed together tend to fight until they cut each other's antennae off, but females huddle together, and apparently even harmonize, their reproductive schedules. This tracks with overall roach ecology, as males tend to leave roach colonies to avoid inbreeding, while female kin stick together, the researchers wrote.
Original article on Live Science. Stephanie Pappas is a contributing writer for Live Science covering topics from geoscience to archaeology to the human brain and behavior. A freelancer based in Denver, Colorado, she also regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association.
So, one female German cockroach could be the matriarch of 35, new roaches. These chestnut-colored insects usually breed in sewers, so their bacteria is especially nasty. American Cockroaches live for about thirty months, which is a long time for a roach. Fortunately, these females do not have very much breeding time.
After about fifteen weeks, females are mature enough to breed. During their peaks, they can produce two oothecas a week. Each egg capsule has about sixteen eggs. But the peak is short lived. After that, American Cockroach females produce one ootheca a month.
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