Sex-specific trade-off under marine heat wave and food limitation: Insights from bioenergetic and intestinal microbiome in mussels

Abstract

Global warming, marine heat waves and subsequent food limitation are projected to be more frequent and intense under future climate change. Understanding the consequences for key marine species such as mussels is critical to ensure sustainability and guide adaptation options. Mussels are not only an economically important species but also considered excellent indicators of environmental changes. This study evaluates the sex-specific effects of marine heat waves and food limitation on the bioenergetics and intestinal flora of the digestive glands of mussels. Heat waves had a significant negative effect on cell energy homeostasis of the digestive gland in female mussels. Food limitation significantly decreased the total energy reserve in the digestive gland of both female and male mussels. Combined food limitation and heat wave led to sex-specific responses with significantly higher cellular energy allocation parameters observed in the digestive gland of female mussels as compared to males. Additionally, 16S rRNA sequencing showed that the intestinal flora of female mussels was more stable, as well as sex-specific differences in the relative abundance of various bacteria phyla. This study highlights the importance to consider sex in studies evaluating the impact of climate change in mussels, and the results can contribute to the development of strategies for sustainable bivalve aquaculture under the growing risks of warming, heatwaves and food limitations.