Environmental challenges and larval resilience: how copper and heat influence the early life mobility of pure and hybrids of Mytilus sp

Behavioral biomarkers are widely recognized as sensitive indicators for monitoring environmental pollution. This study investigated the combined effects of heat stress and copper exposure on the early life stages of two mussel species, Mytilus galloprovincialis, and Mytilus edulis, and their hybrids. Key parameters of motility; Acetylcholinesterase (AChE) activity and swimming behavior were investigated. Our results revealed notable changes in maximum and average swimming speeds in D-larvae, with increased circular trajectories and decreased rectilinear trajectories in response to elevated temperatures and/or copper exposure, particularly in pure and hybrid M. edulis larvae. These behavioral changes could be related to the modulation of the neuro-muscular activity. Thus, a significant increase in the AChE activity of the M.galloprovincialis larvae and their hybrids was observed as a consequence of heat stress and/or metals. This study highlights that; M.galloprovincialis species may be more resilient than Mytilus edulis species to environmental threats and climate change events.