While we can all be thankful there’s no such thing as a cockroach omelet, it is true that roaches lay eggs. Just like birds, pest cockroaches are oviparous, a scientific term meaning their young grow in eggs outside the mother’s body. Unlike chickens, cockroaches don’t sit on their eggs. Instead fertilized roach eggs are carried near the female cockroach’s abdomen in a dark brown, ½-inch, bean-sized protective sac called an ootheca.
American cockroaches, 1.6 to 2 inches in length, are the most common type of large roach pest and fertilized females carry the ootheca for a just few hours or a few days. When Ms. Roach is ready, she deposits the sac in a hidden location—under some furniture or in a dark corner of the basement or kitchen. The roach applies glue-like saliva to the ootheca to hold it in place. When the sac is fresh, it contains a slimy white blob of goop. After about a month, it produces greyish-white cockroach nymphs. They look like little larvae squirming around a bean. They grow up into voracious, prolific cockroaches scampering around your home.
A single American female roach can produce up to 30 ootheca in her lifetime. Each egg capsule contains about 15 embryos. The German cockroach, which is smaller than the American, produces an ootheca of the same size but it will contain up to 40 nymphs.
Ootheca are designed to be nearly invisible to predators like human beings. But if you have a cockroach problem you should grab a pair of gloves and a flashlight and start prying around the dank corners of your home. Make sure to search cabinets, floors, and around water and sewer pipes in the basement. Move furniture and turn chairs over if necessary. Remove cans of food from cupboards and examine floorboards and areas under the stove and refrigerator. If you see any of those little brown beans or squiggly larvae flush them down the toilet. When your search is over, be sure to place roach bait stations around the house wherever ootheca were found to prevent them in the future. Cockroaches are prolific. By laying out bait stations you can stop the problem before the eggs turn into a major infestation.