Print PageUnderstanding why individuals have different probabilities of acquiring an infectious pathogen (“disease risk”) is critical for controlling emerging pathogens. A range of empirical evidence suggests functional traits influence epidemiological parameters that contribute to disease risk, both at the scale of the individual (individual susceptibility and infectivity are dependent on functional traits) and the community (communities with particular functional trait characteristics may be more attractive to vectors, or increase vector abundance, increasing the overall risk within that community). Functional traits, however, also correlate with demographic rates, which may both shape and be shaped by epidemiological dynamics. Here, we explore the relative contribution of functional traits and demography to infection risk, using the example of yellow dwarf viruses, aphid-transmitted multi-host pathogens of grasses. We build on known empirical relationships to explore the immediate disease risk of any individual given its functional traits, across communities where demography reflects a gradient from resource acquisition to resource allocation.
Results/Conclusions
Communities in high nutrient environments dominated by quick-return phenotypes (short lived, fast growing, poorly defended individuals with high tissue nutrient concentrations and metabolic rates) show the highest proportion infected; this proportion drops as demography is more driven by allocation trade-offs, reflecting lower nutrient environments. The functional trait values corresponding to the highest risk of disease varies both along nutrient gradients and as a function of the link between functional traits and epidemiological parameters.
