Effect of habitat-related resources on fatty acid composition and body weight of the invasive Dikerogammarus villosus in an artificial reservoir

Successful invasions are attributed to a combination of adaptations to biotic and abiotic conditions and many studies have highlighted the role of biological traits of invaders in their success. Among the most useful traits for successful establishment in a new ecosystem are the size of the invader and its diet and feeding habits. During the last twenty years, Dikerogammarus villosus has been one of the most successful invaders of large European rivers and lakes. However, regarding feeding habits, results were confusing and sometimes contradictory. In this study, we attempt to define the feeding strategy of D. villosus using their FA content according to sex and the seasonal and the spatial variation in its feeding habit. Our results indicated that D. villosus is rather unspecialized with plasticity in its feeding behaviour, switching between different functional feeding groups depending on seasons, habitats and available resources. The selection of high quality resources may hence provide a strong advantage during the invasion process by optimizing the growth and the reproduction of the invader.