Getting Better May Get You Eaten

Immune response increases predation risk (2012) Otti et al., Evolution 66

Fighting off an infection can use up valuable energy, and also change behaviour, which can lead to enhanced risk of predation
Fighting off an infection can use up valuable energy, and also change behaviour, which can lead to enhanced risk of predation (Image Credit: Gilles San Martin, CC BY-SA 2.0)

The Crux

Parasites and diseases cause a lot of problems for their hosts, stealing resources like blood, food and energy. But fighting off parasites is also a costly process, so hosts have to walk the thin line between using just enough resources to fight off the parasite and using too many, leaving them with nothing. The amount a host invests in their immune response will depend on the specific environment that they live in. For example, in an environment where resources are plentiful, a host may decide that it is worth shaking off a parasite or disease. In areas where resources aren’t, they may choose to save energy.

Introducing predation to a situation further complicates things. Having a lot of predators around naturally means energy conservation becomes even more important. This study examines the risk of predation for an organism that is fighting off an infection.

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