The spread of many diseases depends on the demography and dispersal of arthropod vectors. Classic epidemiological theory typically ignores vector dynamics and instead makes the simplifying assumption of frequency-dependent transmission. Yet, vector ecology may be critical for understanding the spread of disease over space and time and how disease dynamics respond to environmental change. Here, we ask how environmental change shapes vector demography and dispersal, and how these traits of vectors govern the spatiotemporal spread of disease. We developed disease models parameterised by traits of vectors and fit them to experimental epidemics. The experiment featured a viral pathogen (CYDV-RPV) vectored by aphids Rhopalosiphum padi among populations of grass hosts Avena sativa under two rates of environmental resource supply (i.e. fertilisation of the host). We compared a non-spatial model that ignores vector movement, a lagged dispersal model that emphasises the delay between vector reproduction and dispersal, and a travelling wave model that generates waves of infections across space and time. Resource supply altered both vector demography and dispersal. The lagged dispersal model fit best, indicating that vectors first reproduced locally and then dispersed globally among hosts in the experiment. Elevated resources decreased vector population growth rates, nearly doubled their carrying capacity per host, increased dispersal rates when vectors carried the virus, and homogenised disease risk across space. Together, the models and experiment show how environmental eutrophication can shape spatial disease dynamics—for example, homogenising disease risk across space—by altering the demography and behaviour of vectors. A free Plain Language Summary can be found within the Supporting Information of this article.
Bibliographical noteFunding Information:
N. Venkateswaran and A. Cheng helped sample the experiment. A. Sieben led infection diagnosis work. Discussions with L. Shoemaker helped frame the results. Support was funded by NSF IOS 1556674 to A.K.S., E.T.B., and E.W.S. and NSF DEB 1556649 to E.W.S. and E.T.B.
- barley/cereal yellow dwarf virus
- disease ecology