Exogenous control of the feeding activity in the invasive Asian shore crab Hemigrapsus sanguineus (De Haan, 1835)

The Asian shore crab Hemigrapsus sanguineus (De Haan, 1835) is an invasive decapod along the coast of the English Channel and the North Sea where it is displacing the indigenous European green crab Carcinus maenas. Although behavioural traits have been identified as a critical component of invasion success, they remain poorly studied in H. sanguineus. Hence, the present study quantitatively assessed the feeding activity of H. sanguineus in the laboratory under different light and starvation conditions. Non-starved H. sanguineus exhibited an exogenous day-night rhythm driven by a photophobic behaviour. Starved individuals lacked the photophobic behaviour, which may allow H. sanguineus to spend more time foraging than species characterised by true endogenous rhythms. Altogether, the foraging behaviours reported in this work highlight the behavioural flexibility and adaptive nature of this species, which may confer to H. sanguineus a competitive advantage in intertidal environments.