Transgenerational effects influence acclimation to varying temperatures in Aurelia aurita polyps (Cnidaria: Scyphozoa)

Temperature is one of the most important drivers to affect marine ectotherms in the context of anthropogenic climate change modifying seasonal cycles in temperate regions. To reliably predict the impact of climate variability on marine ectotherms, their capacity to adapt to rapid change needs to be understood. Due to fast transmission between generations, transgenerational effects may enable populations to moderate stressors. We examined reproduction across three temperature scenarios and three generations of asexual Aurelia aurita polyps: transgenerational warming, transgenerational cooling, and stable temperatures. Polyps were incubated at three temperatures (15, 17, 19°C) encountered in summertime in Southampton Water. In the first two polyps generations, temperature remained the main driver of polyp reproduction. However, in the third generation parental and grandparental temperature influenced offspring production. These effects appeared most strongly in cooling scenarios: polyps who experienced rapid cooling between generations displayed an immediate drop in reproductive output as opposed to polyps who remained at the same temperature as their parents. Our results highlight that transgenerational effects may require more extreme temperatures or increased numbers of generations to have a measurable impact on a population, highlighting the vulnerability of these organisms to continued climate change.