Bet-hedging as an evolutionary game: the trade-off between egg size and number.
Bet-hedging theory addresses how individuals should optimize fitness in varying and unpredictable environments by sacrificing mean fitness to decrease variation in fitness. So far, three main bet-hedging strategies have been described: conservative bet-hedging (play it safe), diversified bet-hedging (don't put all eggs in one basket) and adaptive coin flipping (choose a strategy at random from a fixed distribution). Within this context, we analyse the trade-off between many small eggs (or seeds) and few large, given an unpredictable environment. Our model is an extension of previous models and allows for any combination of the bet-hedging strategies mentioned above. In our individual-based model (accounting for both ecological and evolutionary forces), the optimal bet-hedging strategy is a combination of conservative and diversified bet-hedging and adaptive coin flipping, which means a variation in egg size both within clutches and between years. Hence, we show how phenotypic variation within a population, often assumed to be due to non-adaptive variation, instead can be the result of females having this mixed strategy. Our results provide a new perspective on bet-hedging and stress the importance of extreme events in life history evolution.
Olofsson
Helen
H
Department of Ecology, Section of Theoretical Ecology, Ecology Building, Lund University, 223 62, Lund, Sweden.
Ripa
Jörgen
J
Jonzén
Niclas
N
D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000235:genetics* / Q000502:physiology*; D052284:Clutch Size / Q000235:genetics*; D005260:Female; D005716:Game Theory; D008954:Models, Biological; D010063:Ovum / Q000502:physiology*