Stage-specific quiescence as a mechanism for synchronizing life cycles to seasons

Seasonal dormancy plays a critical role in synchronizing life cycles to seasons. In previous work, however, we have shown that quiescence-the readily reversible cessation of development in direct response to contemporaneous environmental conditions-acting alone and independent of stage development cannot yield synchronization. Here we demonstrate how stage-specific quiescence(SSQ), with stage dependence based solely on developmental thresholds that differ among stages, is generally sufficient to synchronize semelparous life cycles to seasons. We present an example consistent with this mechanism, compare SSQ with mechanisms based on diapause, and propose some testable hypotheses. Finally, we indicate additional empirical and theoretical work needed to evaluate the applicability of SSQ and its close relatives to a potentially wide range of organisms.