Understanding developmental plasticity as adaptation requires an inter-generational perspective

In this issue of Evolution, Medicine and Public Health, Lea and colleagues argue that there are major advantages to bringing together biomedical and evolutionary perspectives on plasticity. To develop this approach, they propose two contrasting scenarios for ‘developmental plasticity as adaptation’: that it reflects adjustments to resolve the effects of early ‘constraints’, or that it adjusts phenotype to ecological cues in anticipation of similar conditions in adulthood. Yet neither scenario highlights the unique role of maternal phenotype, mediated by maternal investment strategy, in generating such constraints or cues. Developmental plasticity is greatest during the period when all ecological influences on the offspring are transduced by maternal phenotype. If the offspring adapts during this period, then the target of that adaptation is to maternal phenotype. Ignoring the inter-generational source of early constraints or cues prevents development of a comprehensive adaptive framework, because developmental plasticity is fundamentally relevant to the fitness of both offspring and parents.