Iterative development and the scope for plasticity: contrasts among trait categories in an adaptive radiation

Abstract

Phenotypic plasticity can influence evolutionary change in a lineage, ranging from facilitation of population persistence in a novel environment to directing the patterns of evolutionary change. As the specific nature of plasticity can impact evolutionary consequences, it is essential to consider how plasticity is manifested if we are to understand the contribution of plasticity to phenotypic evolution. Most morphological traits are developmentally plastic, irreversible, and generally considered to be costly, at least when the resultant phenotype is mis-matched to the environment. At the other extreme, behavioral phenotypes are typically activational (modifiable on very short time scales), and not immediately costly as they are produced by constitutive neural networks. Although patterns of morphological and behavioral plasticity are often compared, patterns of plasticity of life history phenotypes are rarely considered. Here we review patterns of plasticity in these trait categories within and among populations, comprising the adaptive radiation of the threespine stickleback fish Gasterosteus aculeatus. We immediately found it necessary to consider the possibility of iterated development, the concept that behavioral and life history trajectories can be repeatedly reset on activational (usually behavior) or developmental (usually life history) time frames, offering fine tuning of the response to environmental context. Morphology in stickleback is primarily reset only in that developmental trajectories can be altered as environments change over the course of development. As anticipated, the boundaries between the trait categories are not clear and are likely to be linked by shared, underlying physiological and genetic systems.

How plasticity, genetic assimilation and cryptic genetic variation may contribute to adaptive radiations

“…Foster et al . ; Ghalambor et al . ) and some even feel that a new evolutionary paradigm is necessary (e.g.…”

“…; Foster et al . ), and even behaviour (Cotman & Berchtold ; Torres‐Dowdall et al . ), such as the avoidance of this new environmental cue (e.g.…”

“…; Foster et al . ; Mazzarella et al . ) and pharyngeal jaw shape and dentition in cichlids (Box : Plasticity in cichlids) (e.g.…”

Phenotypic plasticity in breeding plumage signals in both sexes of a migratory bird: responses to breeding conditions

“…This is supported by the fact that a large part of the changes experienced by individuals in signal expression in our study were linked to initial levels. Constraints on plasticity are due to the genetic architecture of traits which in turn has been selected by the ecological and social environment (Scheiner 2002, Foster et al ).…”

How reversible is development? Contrast between developmentally plastic gain and loss of segments in barnacle feeding legs

“…We identify here a new cost associated with developmentally plastic change: asymmetry in the ease, or time lag, of development in one direction versus development in the reverse direction. Although development may be more easily modified by environment earlier rather than later in life (Hoverman and Relyea 2007;Fischer et al 2014;Beaman et al 2016), developmentally plastic morphological changes can and do occur throughout life in many organisms (Relyea 2003;reviewed in Gabriel et al 2005;Neufeld 2012;Ebert et al 2014;Foster et al 2015;Beaman et al 2016). However, the ease with which plastic change is reversed (e.g., the time lag between change in environment and the appropriate phenotypic response) may not be symmetrical.…”