Individual reversible plasticity as a genotype-level bet-hedging strategy

Individual variation in thermally induced plasticity of metabolic rates: ecological and evolutionary implications for a warming world

Energy metabolism is a fundamental property of life providing the energy for all processes and functions within an organism. As it is temperature-dependent, it mediates the effects of changing climate on ectotherm fitness and population dynamics. Though resting metabolic rate is a highly labile trait, part of its variation is individually consistent. Recent findings show that resting metabolic rate contains consistent variation not only in the elevations (intercepts) but also in the slopes of individual thermal dependence curves, challenging the thermal dependence assumption for this trait in several ectotherm taxa. I argue that among-individual variation in thermal metabolic curves represents a previously undetected component of ectotherm response to climate change, potentially affecting their adaptive capacity and population resilience under increasing stochasticity of thermal environment. Future studies need to examine not only the amount of among-individual variation in thermal metabolic curves across phylogenetic contexts but also other aspects concerning its mechanisms and adaptive significance to improve predictions about the impact of climate change on ectotherm population dynamics. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.

Looking to the past to understand the future: linking evolutionary modes of response with functional and life history traits in variable environments

In a variable world, plants must have strategies to deal with environmental conditions as they change. Understanding these strategies is critical since climate change not only affects mean conditions but also affects variability and predictability of those conditions. Doing so requires identifying how functional and life history traits interact throughout the life cycle to drive responses, as well as exploring how past variability will shape future responses. Here, I highlight relevant life history theory for predicting strategies in relation to the nature of environmental variability, relate theory to empirical studies integrating functional and life history traits to understand responses, and identify key areas for future research that will facilitate the application of this understanding toward predicting responses to climate change.

The social evolution of individual differences: Future directions for a comparative science of personality in social behavior

Personality is essential for understanding the evolution of cooperation and conflict in behavior. However, personality science remains disconnected from the field of social evolution, limiting our ability to explain how personality and plasticity shape phenotypic adaptation in social behavior. Researchers also lack an integrative framework for comparing personality in the contextualized and multifaceted behaviors central to social interactions among humans and other animals. Here we address these challenges by developing a social evolutionary approach to personality, synthesizing theory, methods, and organizing questions in the study of individuality and sociality in behavior. We critically review current measurement practices and introduce social reaction norm models for comparative research on the evolution of personality in social environments. These models demonstrate that social plasticity affects the heritable variance of personality, and that individual differences in social plasticity can further modify the rate and direction of adaptive social evolution. Future empirical studies of frequency- and density-dependent social selection on personality are crucial for further developing this framework and testing adaptive theory of social niche specialization.

Characterization, costs, cues and future perspectives of phenotypic plasticity

BACKGROUND

Plastic responses of plants to the environment are ubiquitous. Phenotypic plasticity occurs in many forms and at many biological scales, and its adaptive value depends on the specific environment and interactions with other plant traits and organisms. Even though plasticity is the norm rather than the exception, its complex nature has been a challenge in characterizing the expression of plasticity, its adaptive value for fitness and the environmental cues that regulate its expression.

SCOPE

This review discusses the characterization and costs of plasticity and approaches, considerations, and promising research directions in studying plasticity. Phenotypic plasticity is genetically controlled and heritable; however, little is known about how organisms perceive, interpret and respond to environmental cues, and the genes and pathways associated with plasticity. Not every genotype is plastic for every trait, and plasticity is not infinite, suggesting trade-offs, costs and limits to expression of plasticity. The timing, specificity and duration of plasticity are critical to their adaptive value for plant fitness.

CONCLUSIONS

There are many research opportunities to advance our understanding of plant phenotypic plasticity. New methodology and technological breakthroughs enable the study of phenotypic responses across biological scales and in multiple environments. Understanding the mechanisms of plasticity and how the expression of specific phenotypes influences fitness in many environmental ranges would benefit many areas of plant science ranging from basic research to applied breeding for crop improvement.

Do I build or do I move? Adaptation by habitat construction versus habitat choice

Trait adaptation to a heterogeneous environment can occur through six modes: genetic differentiation of those traits, a jack-of-all-trades phenotypic uniformity, diversified bet-hedging, phenotypic plasticity, habitat choice, and habitat construction. A key question is what circumstances favor one mode over another, and how they might interact if a system can express more than one mode at a time. We examined the joint evolution of habitat choice and habitat construction using individual-based simulations. We manipulated when during the life cycle construction occurred and the fitness value of construction. We found that for our model habitat construction was nearly always favored over habitat choice, especially if construction happened after dispersal. Because of the ways that the various modes of adaptation interact with each other, there is no simple answer as to which will be favored; it depends on details of the biology and ecology of a given system.