The Tide is High: Tidally-Associated Genetic Markers of an Invasive Coastal Crab in the Northwest Atlantic

Abstract

The ecology of invasive marine species holds many mysteries, ranging from the precise mechanics of adaption in foreign environments to the heritability of behaviors in the native range, and the globally-invasive crab Carcinus maenas (L.) provides a good model for looking into the connection between environment, genetics and behavior in invasive populations. To investigate this relationship, I sampled Carcinus maenas adults and juveniles from an array of sites along the Northwest Atlantic coast and examined how local tidal conditions affected genetic variation and allele frequency patterns in four candidate markers hypothesized to be associated with tidal amplitude. Expecting the patterns I revealed to closely mirror those previously discovered in the native range, I found that one of the four tidal markers I used displayed the same allele frequency trend in both the native and invasive ranges. This suggests that tidal amplitude is a likely driver of selection in this species in both native and foreign environments, but sampling more sites in the future is needed for a more conclusive assertion of this idea. Nevertheless, the results of this study offer a promising lead on the relationship between tidal amplitude and genetics in Carcinus maenas, bringing us closer to solving the mystery of environment-behavioral coupling in marine species.