Implications for investigating the adaptive benefit of cavefish traits
Our study provides important context for research on the evolution ofA. mexicanus behavior and metabolism as these traits are known to be influenced by microbiome composition. For example, cavefish have reduced aggression , which can be recapitulated in flies, mice, and hamsters through microbiome manipulation . In addition, cavefish are fat and insulin resistant which is associated with microbiome changes in fish and mammals . When considering the adaptive benefit of A. mexicanus traits recorded in the laboratory, it is important to note that the laboratory environment does not recapitulate either wild habitat (river or cave) and the fish display considerable plasticity in some traits . We showed that laboratory raised fish harbor a more diverse microbiome compared to their field caught counterparts and that the laboratory microbiome contains more of the taxa in wild surface fish compared to the wild cavefish. Our results serve as a foundation for understanding how different microbial taxa impact A. mexicanusphenotypes which will lead to a better understanding of cavefish evolution.