In our study system, Zamzow

et al. (2010) examined host preference by two of the most common macroalgal-associated amphipods between the chemically defended overstory macroalga D. menziesii and the undefended click here understory alga Palmaria decipiens (Reinsch) R.W. Ricker. The amphipod Prostebbingia gracilis does not consume either macroalgal host, although with P. decipiens, this is not because of chemical defenses (Aumack et al. 2010). Prostebbingia gracilis always preferred to associate with the chemically defended D. menziesii in laboratory assays (Zamzow et al. 2010). The amphipod Gondogeneia antarctica, which does consume P. decipiens, but does not consume D. menziesii (Amsler et al. 2009b, Aumack et al. 2010), preferred to associate Selumetinib research buy with (and eat) P. decipiens over D. menziesii when the

experiments were done in normal filtered seawater. However, this preference reversed when scent cues from the omnivorous fish N. coriiceps were present (Zamzow et al. 2010). In further experiments, amphipods associated with D. menziesii were much less likely to be consumed by the omnivorous fish N. coriiceps than those forced to associate with P. decipiens. (Zamzow et al. 2010). N. coriiceps is chemically deterred from consuming D. menziesii in laboratory assays (Amsler et al. 2005) but has been shown to eat P. decipiens in both field and laboratory studies (Iken et al. 1997, 1999, Amsler et al. 2005). Although we have yet to extend such investigations beyond 上海皓元 these species pairs, it is clear that Antarctic amphipods can benefit from associating with chemically defended hosts via an associational defense with respect to one of if not their single most important predators, N. coriiceps. Amphipod distribution patterns in nature are consistent with them behaviorally selecting chemically defended hosts for refuge (Huang et al. 2007, authors’ personal

observations), but, on a biomass basis, there are so very few nondefended macroalgae in the community that this by itself is far from definitive. Moreover, morphology appears to play a role in amphipod choice with an apparent preference for more finely branched, chemically defended species over chemically defended, but blade-forming macroalgae (Huang et al. 2007, Zamzow et al. 2010, authors’ personal observations). Observed differences between amphipod distributions during the night vs. daytime, however, provide stronger supporting evidence for an associational benefit to the amphipods. Aumack et al. (2011a) enumerated amphipods in both day and night collections of closely associated D. menziesii, P. decipiens, and Iridaea cordata (Turner) Bory, a red alga that is also eaten by N. coriiceps (Amsler et al. 2005). N. coriiceps is a visual predator and is much less successful as a predator at night (Donatti and Fanta 2002).