Fitness Functions for Alternative Developmental Pathways in the Timing of Diapause Induction

Abstract

We analyze five commonly occurring ontogenetic relationships between the sensitive period (SP) for diapause induction, during which environmental cues are assessed and the decision is made whether to diapause, and the diapause stage (DS), during which normal development ceases and diapause characteristics prevail. One relationship (case 1), in which both the SP and DS occur in the juvenile stages of the same generation, has previously been analyzed in detail. Here we concentrate on the remaining four developmental pathways. In case 2a, the DS is the adult preceded by a determinate SP. Since a determinate SP has a fixed end before reproduction, adults are committed to reproduction or to diapause before reproducing. In case 2b, the DS is the adult preceded by an indeterminate SP, which has no fixed end and extends into the reproductive adult stage, allowing an adult to reproduce before entering diapause. The parental generation in case 3a determines the diapausing fate of a preadult stage in the next genera...