Meeting Abstract
The European green crab, Carcinus maenas, is a globally invasive species with highly detrimental effects on invaded ecosystems. Molecular techniques have recently allowed to reconstruct the invasion history of this species and have shown that distinct genetically different as well as hybrid populations exist. We compared crab populations collected in Iceland (part of the native range), Maine (from the invasion in 1817), and Newfoundland and Nova Scotia (hybrids between Maine and a second invasion in the 1980s into Canada) for morphology, behavior, and stress tolerance. C. maenas from different regions displayed varied carapace morphology in a 3D shape analysis of homologous morphological points. Nova Scotian crabs were significantly more aggressive than all other populations. However, no differences were found in claw crushing force. When C. maenas were placed into a 5 m diameter mesocosm of eelgrass the hybrid populations, NS and NL, destroyed more plants than other populations. During a low salinity exposure (10 ppt, 72 h) many crabs from Iceland died, or showed significantly reduced motor performance compared to the other populations. Differences in gene expression of cellular stress markers and NaK-ATPase were observed after the salinity exposure. These results highlight key differences between the native, invasive, and hybrid populations. Therefore, behavior, morphology, and physiology of this species need to be considered as distinct traits between different populations and might reflect adaptations to the respective new habitat. Currently, the hybrid population from Nova Scotia is extending southwards into Maine and will most likely create even more damage to an already C. maenas-damaged ecosystem, due to its superior aggression and destructiveness.
