Food makes you a target: disentangling genetic, physiological, and behavioral effects determining susceptibility to infection

Genetics, physiology and behavior are all expected to influence the susceptibility of hosts to parasites. Furthermore, interactions between genetic and other
factors are suggested to contribute to the maintenance of genetic polymorphism in resistance when the relative susceptibility of host genotypes is context dependent. We
used a maternal sibship design and long- and short-term food deprivation treatments to test the role of family-level genetic variation, body condition, physiological
state and foraging behavior on the susceptibility of Lymnaea stagnalis snails to infection by a trematode parasite that uses chemical cues to locate its hosts. In
experimental exposures, we found that snails in the long-term food deprivation treatment contracted fewer parasites than snails that were continuously well-fed,
possibly because well-fed snails grew larger and attracted more transmission stages. When we kept the long-term feeding rates the same, but manipulated the
physiological st...