The diapause response displays rich variability, both within populations as well as between populations, variation that provides the grist for rapid shifts in the diapause response as insects invade new territories or respond to climate change. Variation is evident for not only the decision to enter diapause but also for the timing of its onset and termination. Even progeny from a single egg clutch shows variation in their diapause response. Other variations in the response are noted in few insects that enter and exit diapause repeatedly and among species that exhibit a prolonged diapause that persists for more than 1 year. Prolonged diapause is energetically costly but serves as an important bet-hedging strategy for insects inhabiting an unpredictable environment.