Mechanisms of Plastic Rescue in Novel Environments

Abstract

Adaptive phenotypic plasticity provides a mechanism of developmental rescue in novel and rapidly changing environments. Understanding the underlying mechanism of plasticity is important for predicting both the likelihood that a developmental response is adaptive and associated life-history trade-offs that could influence patterns of subsequent evolutionary rescue. Although evolved developmental switches may move organisms toward a new adaptive peak in a novel environment, such mechanisms often result in maladaptive responses. The induction of generalized physiological mechanisms in new environments is relatively more likely to result in adaptive responses to factors such as novel toxins, heat stress, or pathogens. Developmental selection forms of plasticity, which rely on within-individual selective processes, such as shaping of tissue architecture, trial-and-error learning, or acquired immunity, are particularly likely to result in adaptive plasticity in a novel environment. However, both the induction of plastic responses and the ability to be plastic through developmental selection come with significant costs, resulting in delays in reproduction, increased individual investment, and reduced fecundity. Thus, we might expect complex interactions between plastic responses that allow survival in novel environments and subsequent evolutionary responses at the population level.

Plasticity‐led evolution: A survey of developmental mechanisms and empirical tests

“…These mechanisms, which include, but are not limited to, cytoskeleton formation (Kirschner & Gerhart, 1998), neuron growth and development (Oppenheim, 1991), neuronal connections (Sanes & Lichtman, 1999), tissue architecture (Snell-Rood et al, 2018), vertebrate adaptive immunity (Kirschner & Gerhart, 1998), plant growth and foraging (Hutchings & de Kroon, 1994), habitat choice (Levins, 1968) and trial-and-error learning (West-Eberhard, 2003), can provide high sensitivity to local conditions and thereby might produce adaptive outcomes. These mechanisms, which include, but are not limited to, cytoskeleton formation (Kirschner & Gerhart, 1998), neuron growth and development (Oppenheim, 1991), neuronal connections (Sanes & Lichtman, 1999), tissue architecture (Snell-Rood et al, 2018), vertebrate adaptive immunity (Kirschner & Gerhart, 1998), plant growth and foraging (Hutchings & de Kroon, 1994), habitat choice (Levins, 1968) and trial-and-error learning (West-Eberhard, 2003), can provide high sensitivity to local conditions and thereby might produce adaptive outcomes.…”

“…Through the use of finegrained local responses generated by subunits of the larger phenotype, exploratory mechanisms can yield organized developmental configurations that are wellsuited to the current environment (Kirschner, 1992;Snell-Rood, 2012;Snell-Rood et al, 2018). Through the use of finegrained local responses generated by subunits of the larger phenotype, exploratory mechanisms can yield organized developmental configurations that are wellsuited to the current environment (Kirschner, 1992;Snell-Rood, 2012;Snell-Rood et al, 2018).…”

“…Through the use of finegrained local responses generated by subunits of the larger phenotype, exploratory mechanisms can yield organized developmental configurations that are wellsuited to the current environment (Kirschner, 1992;Snell-Rood, 2012;Snell-Rood et al, 2018). However, the high costs typically associated with such mechanisms may make the phenotypes they produce more prone to genetic assimilation (Scheiner, Barfield, & Holt, 2017;Snell-Rood et al, 2018). However, the high costs typically associated with such mechanisms may make the phenotypes they produce more prone to genetic assimilation (Scheiner, Barfield, & Holt, 2017;Snell-Rood et al, 2018).…”

“…Because signals only activate or inactivate a switch without directly guiding its downstream activity or interactions (Kirschner & Gerhart, 1998), the phenotypic variants produced by deterministic (switch-like) processes under novel conditions may have greater variation in their fitness effects than exploratory mechanisms. Moreover, whether such plasticity is adaptive in a new environment depends on whether that particular environment is novel relative to those environments in which the plasticity evolved (Snell-Rood et al, 2018). This might be expected, at least in part, because switch-like plasticity (e.g., polyphenisms) would have presumably evolved in coordination with cues that predict particular environmental conditions (Moran, 1992;Sultan & Spencer, 2002).…”

“…That is, by chance, any variants produced may be adaptive, maladaptive, or selectively neutral in the new environment. For example, if the environment undergoes an extreme shift or changes in a discrete way (e.g., introduction of new resource or anthropogenic toxin), ancestral switches may not be able to produce a well-adapted phenotype (Snell-Rood et al, 2018). Moreover, whether such plasticity is adaptive in a new environment depends on whether that particular environment is novel relative to those environments in which the plasticity evolved (Snell-Rood et al, 2018).…”