Timing of Entry into Diapause: Optimal Allocation to "Growth" and "Reproduction" in a Stochastic Environment

An organism which can potentially complete several generations during the breeding season is considered. Offspring in each generation can either enter diapause or attempt to grow to maturity and reproduce. The length of the breeding season is variable and any organism not in diapause when it ends dies without leaving offspring. Those organisms in diapause which survive re-emerge to form the breeding population in one yearʹs time. the assumption that all population members experience the same season length in a given year, natural selection can be expected to produce a strategy which maximizes the geometric mean of those descendants entering diapause. Here such an optimal strategy is explicitly determined. This strategy specifies the proportion of the cohort of descendants of an initial female which should be in diapause at each time. The proportion of new offspring entering diapause in each generation under the optimal strategy is then given in terms of the hazard function which specifies the probability the season will end in each generation given that it has not already done so. uations of the diapause model presented are compared with those used to describe the optimal allocation to vegetative and seed production in annual plants. Similarities and differences in the two scenarios are discussed.