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 degrees 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.

Automated summary

Temperature is a significant driver affecting marine ectotherms, especially in the context of climate change altering seasonal patterns in temperate regions. Understanding their ability to adapt to rapid changes is crucial for predicting the impact of climate variability on these organisms. Transgenerational effects, which allow for the transmission of traits between generations, may potentially moderate stressors. Our study on asexual Aurelia aurita polyps revealed that temperature influenced polyp reproduction in the first two generations, but parental and grandparental temperature impacted offspring production in the third generation. The effects were most pronounced in cooling scenarios, where polyps experienced a rapid drop in reproductive output compared to those who remained at the same temperature as their parents. These findings underscore the vulnerability of marine ectotherms to climate change and suggest that transgenerational effects may require more extreme temperatures or additional generations to exert a measurable impact on populations.