Intraspecific plasticity and trans-generational adaptation of reproductive traits and early development in a...

Climate warming is altering the distribution of species, producing range shifts and promoting local extinctions. There is an urgent need to understand the underlying mechanisms that influence the persistence of populations across a species' distribution range in the face of global warming. Ocenebra erinaceus is a marine gastropod that exhibits high intraspecific variability in maternal investment and physiological capacity during early stages, which suggests local adaptation to natal environmental conditions. In this study, reproductive traits and trans-generational adaptation were measured in two subtidal populations: one from the middle (the Solent, UK) and another towards the southern end of their geographic distribution (Arcachon, France). Local adaptation was evaluated with a transfer experiment (i.e. Arcachon females transferred to Solent thermal conditions) and trans-generational adaptation was evaluated in the thermal tolerance response of embryos exposed to temperatures between 10 and 20 °C. This study shows that both populations have similar fitness; however, there are adaptive costs to live under their natal location, resulting in trade-offs between reproductive traits. Transferred females show lower reproductive output, which suggests that females are maladapted to live under a new environment. The trans-generational experiment demonstrates contrasting thermal tolerance ranges between populations. Adaptation to local thermal conditions was observed in transferred embryos, showing poor performance and high mortalities under the new environment. Our results provide a better understanding of intraspecific differences and adaptations across a species' distribution range and provide insights into how climate warming will impact encapsulated species exhibiting location-specific adaptation.