Sex-specific responses of Ruditapes philippinarum to ocean acidification following gonadal maturation

Ocean acidification (OA) can seriously affect marine bivalves at different levels of biological organization, generating widespread consequences on progeny recruitment and population maintenance. Yet, few effort has been devoted to elucidating whether female and male bivalves respond differentially to OA in their reproductive seasons. Here, we estimated differences in physiological responses of female and male Manila clams (Ruditapes philippinarum) to OA during gonadal maturation. In comparison to OA-stressed male clams, females significantly depressed activities in enzymes related to energy metabolism (NKA, T-ATP), antioxidant defence (SOD and MDA), and non-specific immune function (ACP), and downregulated expression of AMPK that plays a key role in cellular metabolism, indicating that sex did significantly affect responses of R. philippinarum to OA. Such sex based differences can be likely couched in energetic terms, given the much more energetically expensive cost of egg production than that of sperms. These results indicate that sex-specific responses to OA during reproductive seasons do exist in marine bivalves, and therefore accounting for such sex specificity is of paramount importance when projecting population sustainability and formulating conservation strategies in an acidifying ocean.

Automated summary

This study investigated the differential physiological responses of male and female Manila clams to ocean acidification. The results showed that female clams had significantly depressed enzyme activities related to energy metabolism, antioxidant defense, and immune function compared to male clams under ocean acidification stress. Sex-based differences in response to ocean acidification exist in marine bivalves, likely due to the energetically expensive cost of egg production.