, 2001; Jara & Perotti, 2010) through a behavioral trade-off Saracatinib cost effect. Our results suggest that the antipredator traits of tadpoles could affect the predation rates of co-occurring tadpole species, since these antipredator traits could modify the fish and the odonate larvae prey preferences. In our experiments, cryptic tadpoles have higher survivorship when co-existing with unpalatable tadpoles in the presence of Aeshna sp. predators and have lower survivorship when co-existing with unpalatable tadpoles in the presence of fish predators. Many odonate predators are not affected by the skin

toxins that make tadpoles unpalatable to fish (Crossland & Alford, 1998; Hero et al., 2001; Smith et al., 2008; Ballengée & Sessions, 2009). For these predators, our experiment demonstrated that the cryptic behavior was more efficient at avoiding predation. In temporary ponds, where fish are generally absent and the predation pressure of odonate predators can be substantial (Van Buskirk, 1988; Scheffer et al., 2006; Jara & Perotti, 2010), the tadpole predation risk could be measured by the activity of the tadpole in the presence of the predator (Hero et al., 2001). Thus, cryptic

tadpoles could reduce Nutlin-3a supplier their mortality by reducing their foraging activity (Hero et al., 2001). However, as unpalatable tadpoles exhibit a slow but constant swimming activity pattern and show only a small reduction in their activity in the presence of predators (D’Heursel & Haddad, 1999; Hero et al., 2001; Jara & Perotti, 2009, 2010; F. Nomura,

unplubl. data), the cryptic behavior also affects the predation risk of unpalatable tadpoles, making unpalatable tadpoles more easily detected by odonate predators. Conversely, unpalatable tadpoles could modify 上海皓元 the predator’s prey preference, when the predator has some learning ability and is affected by its skin toxins. In our experience experiment, inexperienced fishes captured and rejected the R. schneideri tadpoles, sometimes chewing them before rejecting the tadpole (F. Nomura, pers. obs.). Although this behavior accounted for the majority of unpalatable tadpole mortality, experienced fish were never observed displaying this ‘tasting’ behavior (F. Nomura, pers. obs.). Despite the fact that the fish predators used are generalists, the prey preference of the fish was modified by unpalatability and improved by learning, because experienced fish learned to avoid unpalatable tadpoles, but they also learned to select and prey more efficiently on palatable tadpoles. Consequently, our results show that the experienced fish had a greater predation rate on E. nattereri compared with the inexperienced fish. As demonstrated by the previous experiment, cryptic behavior was not only ineffective against the fish, but it also became even less effective with fish experience.