As the earth’s climates continue to change at increasing rates, temporal resource availability is shifting, changing the fitness landscape associated with seasons. It is becoming increasingly important to understand how organisms can evolve and adapt to deal with these new (and potentially less consistent) optimal emergence times (or germination, hatching, breeding, etc times). We constructed a general mathematical model to represent the adaptive evolution of emergence strategies that integrate multiple environmental cues (photoperiod, temperature, precipitation), and applied this model to real and simulated climate data to answer three questions. First, how should organisms integrate multiple environmental cues to produce emergence strategies that are effective in complex and dynamic climates? Second, how should emergence strategies evolve under different climate regimes? Third, how robust are different emergence strategies to changes in climate?
Results/Conclusions
Our simulations showed that organisms benefitted from using multiple cues, with temperature being more valuable in climates with high year-to-year variation but low day-to-day variation, and photoperiod being more valuable in climates with more day-to-day variation. We found that different strategies for responding to cues could produce similar behavior in a given climate. This let different populations evolve divergent genotypes that gave similar phenotypes and nearly equal geometric mean fitness. This genetic differentiation between populations remained hidden in the historic climate regimes, but when populations were exposed to novel climates, the divergent genotypes produced noticeably different emergence times. This pattern matches empirical studies which have shown that species and even populations in the same region have had different phenological shifts in response to climate change. Our work provides a framework for thinking about evolution of emergence, and offers intuitions for how changes in climates may influence the phenology of important life history events.