Many insects possess the plastic ability to either develop directly to adulthood, or enter diapause and postpone reproduction until the next year, depending on environmental cues (primarily photoperiod) that signal the amount of time remaining until the end of the growth season. These two alternative pathways often differ in co-adapted life history traits, e.g. with slower development and larger size in individuals headed for diapause. The developmental timing of these differences may be of adaptive...