Plastic adjustments of biparental care behaviour across embryonic development under elevated temperature in a marine ectotherm

Phenotypic plasticity in parental care investment allows organisms to promptly respond to rapid environmental changes by potentially benefiting offspring survival and thus parental fitness. To date, a knowledge gap exists on whether plasticity in parental care behaviours can mediate responses to climate change in marine ectotherms. Here, we assessed the plasticity of parental care investment under elevated temperatures in a gonochoric marine annelid with bi-parental care, Ophryotrocha labronica, and investigated its role in maintaining the reproductive success of this species in a warming ocean. We measured the time individuals spent carrying out parental care activities across three phases of embryonic development, as well as the hatching success of the offspring as a proxy for reproductive success, at control (24°C) and elevated (27°C) temperature conditions. Under elevated temperature we observed: (i) a significant decrease in total parental care activity, underpinned by a decreased ...