A case for a joint strategy of diversified bet hedging and plasticity in the pea aphid wing polyphenism

Abstract

Phenotypic plasticity and diversified bet hedging are strategies for coping with variable environments. Plasticity is favoured when an organism can predict future conditions using environmental cues, while bet hedging is favoured when predictive cues are not available. Theoretical analyses suggest that many organisms should use a mixture of both strategies, because environments often present both scenarios. Here, we examine if the pea aphid wing polyphenism, a well-known case of plasticity, is potentially a mixture of plasticity and bet hedging. In this polyphenism, asexual females produce more winged offspring in crowded conditions, and wingless offspring in uncrowded conditions. We find that pea aphids use plasticity to respond to crowding and we find considerable genetic variation for this response. We further show that individual aphids produce both winged and wingless offspring, consistent with the variability expected in a bet hedging trait. We conclude that the pea aphid wing polyphenism system is probably a mixture of plasticity and bet hedging. Our study adds to a limited list of empirical studies examining mixed strategy usage, and suggests that mixed strategies may be common in dispersal traits.

Short‐term insurance versus long‐term bet‐hedging strategies as adaptations to variable environments

“…There is still more work to be done in reconciling bet‐hedging theory with other types of adaptations to variable and unpredictable environments, such as specialist versus generalist strategies (Gilchrist ; Buckley and Huey ), interactions with phenotypic plasticity (Simons ; Grantham et al. ), the evolution and maintenance of sexual reproduction (Burke and Bonduriansky ; Li et al. ; Gerber et al.…”

“…We have demonstrated several results linking theory concerning individual-level strategies from behavioral ecology with genotype-level adaptations from evolutionary biology in context of environmental uncertainty. There is still more work to be done in reconciling bet-hedging theory with other types of adaptations to variable and unpredictable environments, such as specialist versus generalist strategies (Gilchrist 1995;Buckley and Huey 2016), interactions with phenotypic plasticity (Simons 2014;Grantham et al 2016), the evolution and maintenance of sexual reproduction (Burke and Bonduriansky 2017;Li et al 2017;Gerber et al 2018), and topics on human development and decision-making (McNamara et al 2011;Fawcett et al 2014;Higginson et al 2016). An important next step is now to connect these theoretical studies to real world examples and quantitative studies of organisms in the lab and in the wild, for example if we are to understand how populations might respond to current human-induced rapid environmental change.…”

Interactive and sex‐specific life‐history responses ofCulex pipiensmosquito larvae to multiple environmental factors

“…For instance, pea aphids produced more winged offspring after encountering high‐density environment (i.e. phenotypic plasticity; Grantham et al ., ). However, individual pea aphids stochastically produced different proportions of offspring phenotypes, supporting the variability expected from a bet‐hedging trait (Grantham et al ., ).…”

“…phenotypic plasticity; Grantham et al ., ). However, individual pea aphids stochastically produced different proportions of offspring phenotypes, supporting the variability expected from a bet‐hedging trait (Grantham et al ., ). Hence, polymorphism in pea aphid wings seemed to be a mixture of phenotypic plasticity and bet‐hedging strategies (Grantham et al ., ).…”

Optimal germination timing in unpredictable environments: the importance of dormancy for both among‐ and within‐season variation

“…Desert winter annuals are model organisms for this question, both empirically (Clauss & Venable 2000;Tielb€ orger et al 2012;Gremer & Venable 2014;Gremer et al 2016) and theoretically (Cohen 1966(Cohen , 1967Ellner 1985a, b). Bet hedging via dormancy has additionally been demonstrated in insects (Rajon et al 2014;Grantham et al 2016), rotifers (Tarazona et al 2017), fish (Furness et al 2015) and bacteria (Sturm & Dworkin 2015).…”