Cockroaches undergo egg and nymphal stages before becoming adults. Eggs produced by female cockroaches are enclosed in resilient egg cases known as oothecae. The oothecae of cockroach species contain a range of nymph numbers which is dependent on species. The time it takes for eggs to hatch into nymphs varies between species as well and depends upon environmental conditions. Nymphs free themselves from the oothecae by working in concert.
Nymphs resemble adults in appearance and behavior, although they are smaller in size and do not have wings. Nymphs undergo a series of molts before becoming fully mature adults. After the final molt, nymphs of some cockroaches are equipped with wings. After nymphs molt, they are pale in color. Nymphal cockroaches that have recently molted are often misidentified as albino roaches. Within a few hours, they will darken to the proper color.
Adult cockroaches have an average lifespan of around a year but it depends on species. Temperature and other environmental conditions greatly affect the survival of cockroaches. Adult cockroaches reproduce rapidly and are known scavengers. Cockroaches usually are nocturnal. Roaches that are active during the day may be victims of overcrowding or may be looking for food or water.