|dc.description.abstract||In order to fully understand an organism's behaviours the interactions between
multiple enemies or selective pressures need to be considered, as these interactions are
usually far more complex than the simple addition of their effects in isolation. In this
thesis, I consider the impact of multiple enemies (fish predators and parasites) on the
behaviour of three larval anurans (Lithobates sylvaticus, L. clamitans and L.
catesbeianus). I also determine whether species that differ in life-histories and habitat
preferences possess different antipredator mechanisms and how this affects species
responses to multiple enemies. I show that the three Ranid larvae respond differently to
the trade-off imposed by the presence of both fish predators and trematode parasites
within the environment. The two more permanent pond breeders (L. clamitans and L.
catesbeianus) increased activity when in the combined presence of predators and
parasites. In contrast, the temporary pond breeder (L. sylvaticus) decreased activity in the
combined presence of predator and parasites, in the same manner as they responded to
fish alone. Further, the presence of fish along with parasites increased the susceptibility
of both L. sylvaticus and L. clamitans to trematode infection, whereas parasite infection
in L. catesbeianus was unaffected by the presence of fish. A second experiment to assess
palatability of the three anuran species to fish, revealed a range of palatabilities, with L.
catesbeianus being least palatable, L. clamitans being somewhat unpalatable, and L.
sylvaticus being highly palatable. This result helps to explain the species differences in
tthe observed behaviour to the combined presence of fish and parasites. In conclusion, the results from this study highlight the importance of considering multiple selective pressures faced by organisms and how this shapes their behaviour.||en_US