title: Correlations between physical and chemical defences in plants: tradeoffs, syndromes, or just many different ways to skin a herbivorous cat?
abstract: Most plant species have a range of traits that deter herbivores. However, understanding of how different defences are related to one another is surprisingly weak. Many authors argue that defence traits trade off against one another, while others argue that they form coordinated defence syndromes. We collected a dataset of unprecedented taxonomic and geographic scope (261 species spanning 80 families, from 75 sites across the globe) to investigate relationships among four chemical and six physical defences. Five of the 45 pairwise correlations between defence traits were significant and three of these were tradeoffs. The relationship between species' overall chemical and physical defence levels was marginally nonsignificant (P = 0.08), and remained nonsignificant after accounting for phylogeny, growth form and abundance. Neither categorical principal component analysis (PCA) nor hierarchical cluster analysis supported the idea that species displayed defence syndromes. Our results do not support arguments for tradeoffs or for coordinated defence syndromes. Rather, plants display a range of combinations of defence traits. We suggest this lack of consistent defence syndromes may be adaptive, resulting from selective pressure to deploy a different combination of defences to coexisting species.
authors: Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
authors: Angela T
authors: AT
authors: Moles
authors: Terrestrial Ecology Group, Departamento Interuniversitario de Ecología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin s/n, Cantoblanco, E-28049, Madrid, Spain.
authors: Begoña
authors: B
authors: Peco
authors: Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia.
authors: Ian R
authors: IR
authors: Wallis
authors: Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia.
authors: William J
authors: WJ
authors: Foley
authors: Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
authors: Alistair G B
authors: AGB
authors: Poore
authors: Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, MN, 55108, USA.
authors: Eric W
authors: EW
authors: Seabloom
authors: School of Botany, University of Melbourne, Parkville, VIC, 3010, Australia.
authors: Peter A
authors: PA
authors: Vesk
authors: Centro Nacional Patagónico, CONICET, Blvd. Brown s/n, 9120, Puerto Madryn, Argentina.
authors: Alejandro J
authors: AJ
authors: Bisigato
authors: Centro Nacional Patagónico, CONICET, Blvd. Brown s/n, 9120, Puerto Madryn, Argentina.
authors: Lucrecia
authors: L
authors: Cella-Pizarro
authors: Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA, 02540, USA.
authors: Connie J
authors: CJ
authors: Clark
authors: Jasper Ridge Biological Preserve, Stanford University, Stanford, CA, 94305-5020, USA.
authors: Philippe S
authors: PS
authors: Cohen
authors: Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit, Amsterdam, the Netherlands.
authors: William K
authors: WK
authors: Cornwell
authors: School of Marine and Tropical Biology and Centre for Tropical Environmental and Sustainability Science, James Cook University, PO Box 6811, Cairns, QLD, Australia.
authors: Will
authors: W
authors: Edwards
authors: National Environmental Research Institute, University of Aarhus, 8420, Rønde, Denmark.
authors: Rasmus
authors: R
authors: Ejrnaes
authors: Facultad de Ciencias Forestales y Medio Ambiente, Universidad Nacional de San Antonio Abad del Cusco, Jr. San Mart í n 451, Madre de Dios, Peru.
authors: Therany
authors: T
authors: Gonzales-Ojeda
authors: Climate Impacts Research Centre, Department of Ecology and Environmental Sciences, Umeå University, Abisko Naturvetenskapliga Station, 98107, Abisko, Sweden.|Department of Biology, NTNU, 7491, Trondheim, Norway.
authors: Bente J
authors: BJ
authors: Graae
authors: School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA, 5005, Australia.
authors: Gregory
authors: G
authors: Hay
authors: Department of Biological Sciences, University of Zambia, PO Box 32379, Lusaka, 10101, Zambia.
authors: Fainess C
authors: FC
authors: Lumbwe
authors: School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
authors: Benjamín
authors: B
authors: Magaña-Rodríguez
authors: School of Marine and Tropical Biology, James Cook University, Townsville, QLD, 4811, Australia.|Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW, 2751, Australia.
authors: Ben D
authors: BD
authors: Moore
authors: Universidad Nacional de la Patagonia Austral, INTA, CONICET, 9400, Rio Gallegos, Santa Cruz, Argentina.
authors: Pablo L
authors: PL
authors: Peri
authors: Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA, 02540, USA.
authors: John R
authors: JR
authors: Poulsen
authors: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
authors: James C
authors: JC
authors: Stegen
authors: Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.|Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag X7, Claremont, 7735, South Africa.
authors: Ruan
authors: R
authors: Veldtman
authors: Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden.
authors: Hugo
authors: H
authors: von Zeipel
authors: Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.
authors: Nigel R
authors: NR
authors: Andrew
authors: Environmental Futures Centre, Griffith School of Environment, Griffith University, Nathan, QLD, 4111, Australia.
authors: Sarah L
authors: SL
authors: Boulter
authors: Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, MN, 55108, USA.
authors: Elizabeth T
authors: ET
authors: Borer
authors: Department of Systems Ecology, Institute of Ecological Science, Vrije Universiteit, De Boelelaan 1087, NL-1081 HV, Amsterdam, the Netherlands.
authors: Johannes H C
authors: JHC
authors: Cornelissen
authors: Lab. Ecotono, CRUB-UNC, INIBIOMA-CONICET, 8400, Bariloche, Argentina.
authors: Alejandro G
authors: AG
authors: Farji-Brener
authors: School of Marine and Tropical Biology, James Cook University, Townsville, QLD, 4811, Australia.
authors: Jane L
authors: JL
authors: DeGabriel
authors: Facultad de Ciencias Forestales, University of Nuevo Leon, Linares, 67700, Mexico.
authors: Enrique
authors: E
authors: Jurado
authors: National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, DK- 4000, Roskilde, Denmark.
authors: Line A
authors: LA
authors: Kyhn
authors: Low Ecological Services, PO Box 3130, Alice Springs, NT, 0871, Australia.
authors: Bill
authors: B
authors: Low
authors: Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
authors: Christa P H
authors: CPH
authors: Mulder
authors: Australian Centre for Sustainable Catchments, University of Southern Queensland, Toowoomba, QLD, 4350, Australia.
authors: Kathryn
authors: K
authors: Reardon-Smith
authors: Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, 58190, México.
authors: Jorge
authors: J
authors: Rodríguez-Velázquez
authors: Department of Zoology, University of Zululand, Private Bag x1001, Kwadlangezwa, 3886, Kwazulu-Natal, South Africa.
authors: An
authors: A
authors: De Fortier
authors: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, China.
authors: Zheng
authors: Z
authors: Zheng
authors: CONICET and Instituto de Ecología Regional, Universidad Nacional de Tucumán, Yerba Buena, 4107, Tucumán, Argentina.
authors: Pedro G
authors: PG
authors: Blendinger
authors: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA.
authors: Brian J
authors: BJ
authors: Enquist
authors: Department of Biology, NTNU, 7491, Trondheim, Norway.
authors: Jose M
authors: JM
authors: Facelli
authors: Department of Biology, Washington University in St. Louis, Box 1137, St Louis, MO, 63105, USA.
authors: Tiffany
authors: T
authors: Knight
authors: Curtin Institute for Biodiversity and Climate, Curtin University, PO Box U1987, Perth, WA, 6845, Australia.
authors: Jonathan D
authors: JD
authors: Majer
authors: Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, 58190, México.
authors: Miguel
authors: M
authors: Martínez-Ramos
authors: School of Geography & Environmental Studies, University of Tasmania, Hobart, TAS, 7001, Australia.
authors: Peter
authors: P
authors: McQuillan
authors: School of Mathematics and Statistics and Evolution & Ecology Research Centre, The University of New South Wales, Sydney, NSW, 2052, Australia.
authors: Francis K C
authors: FKC
authors: Hui
mesh_terms: D016000:Cluster Analysis; D010944:Plants / Q000737:chemistry* / Q000276:immunology*; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable