Can genetically based clines in plant defence explain greater herbivory at higher latitudes?
Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences.
Department of Biology, University of Toronto at Mississauga, Mississauga, ON, L5L 1C6, Canada.|Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada.
Daniel N
DN
Anstett
Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, Turku, FI-20014, Finland.
Jeffrey R
JR
Ahern
Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E5, Canada.
Julia
J
Glinos
Department of Biology, University of Toronto at Mississauga, Mississauga, ON, L5L 1C6, Canada.
Nabanita
N
Nawar
Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, Turku, FI-20014, Finland.
Juha-Pekka
JP
Salminen
Department of Biology, University of Toronto at Mississauga, Mississauga, ON, L5L 1C6, Canada.|Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada.
Marc T J
MT
Johnson
D005075:Biological Evolution; D002170:Canada; D014644:Genetic Variation; D060434:Herbivory; D031665:Oenothera biennis / Q000235:genetics / Q000502:physiology*; D010636:Phenols / Q000378:metabolism*; D010641:Phenotype; D014481:United States
D010636:Phenols
Biogeography; Oenothera biennis; climatic gradient; common garden; ellagitannins; flowering time; herbivory; latitude; macroecology