Not all roach eggs are the same size. How to identify cockroach eggs? Some evidence indicates that cockroaches have been on earth for over 350 million years. There are three stages in the life cycle: egg, nymph and adult. Female produce egg cases called oothecae. Some species drop the egg case, while other species carry it until the eggs are ready to hatch. One ootheca can contain up to 50 eggs. A female cockroach can produce multiple cases over her lifetime. Because they produce so many eggs and feed on a wide variety of materials, their population grows very rapidly. The egg cases are so distinctive in shape and size that they can be used to determine the extent and identity of an infestation.
The German (Blattella germanica) cockroach’s egg cases are light brown in color and typically measure about 1/3 inch (8–10mm) in length. A female German cockroach carries an egg capsule containing around 40 eggs. The female may produce up to 8 cases in a lifetime. Under ideal conditions, they may live up to 12 months. The German cockroach carries the ootheca and then drops it about the time the eggs hatch. The hatchlings are initially bright white nymphs, but their outer covering darkens as it hardens, usually within 3 hours. Development from eggs to adults takes 3-4 months.
The American (Periplaneta americana) cockroach’s ootheca is mahogany brown in color and measures approximately 1/3-inch (8–10mm) in length. One female may create 15 to 90 oothecae in her lifetime, with each capsule containing 14 to 16 eggs. The female American cockroach carries the ootheca for two days in a safe, hidden location. Immature cockroaches will emerge from the ootheca within 24 to 38 days. Young nymphs are grayish-brown with each progressive molt becoming more reddish brown. After becoming an adult, a female cockroach will mate and produce an egg case in 3 to 7 days.
The brown-banded (Supella longipalpa) cockroach’s ootheca is yellowish or reddish-brown in color and averages 1/4-inch in length. The brownbanded female carries the capsule for 24 to 48 hours before gluing it to some object. Females of this species produce up to 20 cases in one lifetime, each case contains 16 eggs. Nymphs are identifiable by two yellow bands that cross their upper abdomens. Brown-banded nymphs develop fully within 3-6 months. Adult cockroaches are light brown to glossy dark brown. Males are capable of flight.