|Small is profitable: No support for the optimal foraging theory in sea stars Asterias Rubens foraging on the blue edible mussel Mytilus edulis|Hummel, C.; Honkoop, P.; van der Meer, J. (2011). Small is profitable: No support for the optimal foraging theory in sea stars Asterias Rubens foraging on the blue edible mussel Mytilus edulis. Est., Coast. and Shelf Sci. 94(1): 89-92. dx.doi.org/10.1016/j.ecss.2011.05.028
In: Estuarine, Coastal and Shelf Science. Academic Press: London; New York. ISSN 0272-7714; e-ISSN 1096-0015, meer
Asterias Linnaeus, 1758 [WoRMS]; Mytilus Linnaeus, 1758 [WoRMS]; Mytilus edulis Linnaeus, 1758 [WoRMS]
sea stars; Asterias; mussels; Mytilus; predation; size preference;cafeteria trial
Doubt has been shed recently on the most popular optimal foraging theory stating that predators should maximize prey profitability, i.e., select that prey item that contains the highest energy content per handling time. We hypothesized that sea stars do not forage on blue mussels according to the classical optimal foraging theory but are actively avoiding damage that may be caused by e.g. capture of foraging on too-strong mussel shells, hence the sea stars will have a stronger preference for mussels that are smaller than the most profitable ones. Here we present experimental evidence of the sea star Asterias rubens as a predator that indeed chooses much smaller blue mussels Mytilus edulis to forage on than the most profitable ones. Hence this study does not support the optimal foraging theory. There may be other constraints involved in foraging than just optimizing energy intake, for example predators may also be concerned with preventing potential loss or damage of their foraging instruments.