Constraints on the evolution of phenotypic plasticity: limits and costs of phenotype and plasticity

Abstract

Phenotypic plasticity is ubiquitous and generally regarded as a key mechanism for enabling organisms to survive in the face of environmental change. Because no organism is infinitely or ideally plastic, theory suggests that there must be limits (for example, the lack of ability to produce an optimal trait) to the evolution of phenotypic plasticity, or that plasticity may have inherent significant costs. Yet numerous experimental studies have not detected widespread costs. Explicitly differentiating plasticity costs from phenotype costs, we re-evaluate fundamental questions of the limits to the evolution of plasticity and of generalists vs specialists. We advocate for the view that relaxed selection and variable selection intensities are likely more important constraints to the evolution of plasticity than the costs of plasticity. Some forms of plasticity, such as learning, may be inherently costly. In addition, we examine opportunities to offset costs of phenotypes through ontogeny, amelioration of phenotypic costs across environments, and the condition-dependent hypothesis. We propose avenues of further inquiry in the limits of plasticity using new and classic methods of ecological parameterization, phylogenetics and omics in the context of answering questions on the constraints of plasticity. Given plasticity's key role in coping with environmental change, approaches spanning the spectrum from applied to basic will greatly enrich our understanding of the evolution of plasticity and resolve our understanding of limits.

Evolutionary neuroscience of cumulative culture

“…Where possible, natural selection is expected to reduce costs by "canalizing" plastic responses to recurring environmental situations as automatic parts of normal development (68). The tethering hypothesis suggests that such innate specializations are most likely to be found in relatively heritable sensorimotor systems and with respect to behaviors/stimuli that have been relatively invariant over long periods of time.…”

Kidney morphology and candidate gene expression shows plasticity in sticklebacks adapted to divergent osmotic environments

“…One explanation could be that osmoregulatory plasticity may be costly to maintain, but nevertheless adaptive for populations such as MAR(H) that reside in fluctuating environments characterized by daily salinity variations due to tidal cycles (salinity ranges from 17 to 24 ppt) and even more dramatic seasonal changes associated with spawning and egg rearing in freshwater. Adaptation to the relative osmotic stability of the low-salinity environment should select for more canalized and/or specialist genotypes (DeWitt et al, 1998;Kvitek and Sherlock, 2013;Murren et al, 2015). Conversely, residency in a less heterogeneous environment may simply reflect a relaxation of selection, which in turn might yield a loss of plasticity via random mutational processes Maughan et al, 2007).…”

Developmental plasticity increases at the northern range margin in a warm-dependent amphibian

“…The lack of genetic variation typical of many populations living in marginal areas has been pointed out as a classic constraint for the evolution and maintenance of high levels of plasticity (Schlichting and Pigliucci 1998;Murren et al 2015). Interestingly, we detected the highest levels of developmental plasticity in the marginal Swedish pool frog populations, which harbour very low variability in genetic markers (Sj€ ogren 1991;Zeisset and Beebee 2001).…”