The life cycle of an insect describes the development of an insect from the egg stage to adult. The process is referred to as metamorphosis. Metamorphosis is the process that the insects undergo to change from egg to adult. During complete metamorphosis, the insect egg is laid and when the egg hatches, a larva emerges that has little resemblance to adults. After feeding for a period of time, the larva changes to a new appearance. This stage in development is called the pupal stage. During the pupal stage, the insect will rest for some time before completing the final stage in development. When the pupa develops into an adult and emerges, the final stage of metamorphosis is achieved.
Bed bugs evolve in a process called simple metamorphosis. This means that the juveniles have the appearance of adults and there is no resting or pupal stage. So the bed bug life cycle goes from egg to nymph, progressing through five nymphal stages, to adult, which then lays eggs and the process starts again.
Eggs take about a week to hatch. Bed bugs are most active when their living space is just under body temperature, so a room temperature that is about 80° Fahrenheit is hospitable. After hatching, the nymphal stages begin and if there is adequate food, temperature, and humidity of about 75%, bed bugs will thrive. They can produce several generations per year, so egg to egg can be timed in just a few months.
Female bed bugs can lay hundreds of eggs in her lifetime if there is an adequate population of males to ensure continuous egg production. Most eggs will hatch if conditions are right and newly hatched nymphs must feed soon after hatching.
While it is rare in normal populations, there are documented cases where bed bugs have been dormant and waiting for a host for over a year. Moreover, there have been rare cases where bed bugs have survived two years without feeding.