Figure 1.

Critical photoperiod (CPP). (a) CPP is determined by exposing separate cohorts of diapausing larvae to different static day lengths and plotting percentage of pupation as a function of day length. Typically, the 50% intercept on the day-length axis defines the critical photoperiod, which is used as a proxy for the entire response curve. (b) Critical photoperiod defined as the 0 intercept on a logit scale, where Logit=Log₁₀[%/(100−%)] and values of 0% and 100% are set equal to 1% and 99%, respectively. This definition takes into account the entire photoperiodic response curve.