Local context drives infection of grasses by vector-borne generalist viruses.
Host characteristics commonly determine infection risk, but infection can also be mediated by regional- or local-scale variation in the biotic and abiotic environment. Experiments can clarify the relative importance of these factors. We quantified drivers of infection by barley and cereal yellow dwarf viruses (B/CYDV), a group of generalist, vector-borne grass pathogens, at hierarchically nested spatial scales (10(5)-1 m) by planting individuals of six common grass species into five Pacific Coast grassland sites spanning 7 degrees of latitude (> 5000 total hosts) and applying a factorial combination of nitrogen and phosphorus fertilizer. Infection differed most among experimental blocks (10(2)-10(3) m scale), suggesting that local factors control infection risk; infection increased with cover of long-lived hosts and phosphorus, but not nitrogen, fertilization. For B/CYDV, local context more strongly predicts infection risk than host species traits or regional context; such spatially nested experiments can clarify the factors underlying variation in infection risk.
Borer
Elizabeth T
ET
Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA. borer@umn.edu
Seabloom
Eric W
EW
Mitchell
Charles E
CE
Power
Alison G
AG
D000818:Animals; D001042:Aphids / Q000502:physiology; D004199:Disease Vectors; D010942:Plant Viruses / Q000472:pathogenicity*; D006109:Poaceae / Q000821:virology*