Parasites and global warming: net effects of temperature on an intertidal host–parasite system

Climate changes, particularly global warming, are likely to impact host–parasite interactions. However, our understanding of the effects of environmental factors on marine host–parasite systems is limited. We conducted a series of laboratory experiments on the effects of temperature on all transmission steps of the intertidal trematodeMaritrema novaezealandensisfrom its first intermediate snail hostZeacumantus subcarinatusto the second intermediate amphipod hostParacalliope novizealandiae. By measuring output of cercarial transmission stages from snails, cercarial survival and infectivity, susceptibility of amphipods to infections, amphipod survival and parasite development within amphipods, we evaluated overall net temperature effects. At low temperatures (