Bet hedging in evolutionary ecology with an emphasis on insects

Authors: Hopper, Keith

Submitted to: Reference Module in Life Sciences
Publication Type: Book / Chapter
Publication Acceptance Date: 2/13/2018
Publication Date: 2/14/2018
Citation: Hopper, K.R. 2018. Bet hedging in evolutionary ecology with an emphasis on insects. Reference Module in Life Sciences. Published (Online). https://doi.org/10.1016/B978-0-12-809633-8.90409-6..
DOI: https://doi.org/10.1016/B978-0-12-809633-8.90409-6

Interpretive Summary: All living creatures evolve in variable environments, and natural selection yields various responses to this variability. Such responses include plasticity, genetic variation, and bet hedging. If the future environment cannot be predicted from current cues, bet hedging may evolve. For bet hedging to be favored, it must yield a higher geometric mean fitness, and it does this by lowering temporal variation in fitness at the expense of arithmetic mean fitness. Bet hedging has implications for insect pest management. Spatial bet hedging by parasitic wasps might explain low levels of parasitism and thus lack of impact of biological control agents; spatial bet hedging by herbivores might explain patterns of attack on crops. Both diapause and migration affect management of insect pests; thus, understanding how bet hedging affects them is important for sustainable solutions to pest problems.

Technical Abstract: All living creatures evolve in variable environments, and natural selection yields various responses to this variability. Such responses include phenotypic plasticity, genetic polymorphisms, and bet hedging. If the future environment cannot be predicted from current cues, natural selection may favor bet hedging. For bet hedging to be favored, it must yield a higher geometric mean fitness and it does this by lowering temporal variation in fitness at the expense of arithmetic mean fitness. Bet hedging has been divided into two types: conservative, where a single phenotype avoids risks, and diversified, where a variety of phenotypes are expressed by a single genotype. Bet hedging can occur over time, space, or both, and three situations for bet hedging can be usefully distinguished: temporal, metapopulation, and within-generation. These categories are extremes of gradients determined by the variance in fitness among individuals and the correlations in fitness among individuals of a given genotype. Here I summarize the theory behind bet hedging, discuss the kinds of evidence to test for bet hedging, and then review evidence for bet hedging in diapause duration, migration polyphenism, spatial distribution of oviposition, polyandry, and other traits.