Behavioral responses of clams to recurrent marine heatwaves.

Marine heatwaves (MHWs) have increased strikingly in past decades, leading to dramatic changes in global marine ecosystems. As dominant infaunal species in coastal ecosystems, clams play a critical ecological role, but little is known about their behavioral responses to intensifying MHWs. Here, we investigated behavioral performances and associated gene expressions of an ecologically and economically important clam species, Ruditapes philippinarum, under recurrent scenarios of MHWs. While burrowing behaviors of R. philippinarum were not significantly affected by low-intensity MHWs, its burrowing ability decreased significantly when acutely exposed to MHWs occurring at high-intensity. Virtually unaffected behavioral performances, yet, were shown in clams under repeated scenarios of MHWs, in line with significantly increased expressions of genes closely associated with energy metabolism and behavioral neuroscience. These findings contribute to a better understanding of behavioral responses of infaunal organisms to MHWs and make a leap forward in linking climate change to bioturbation in marine ecosystems.