title: Impacts of silicon-based grass defences across trophic levels under both current and future atmospheric CO2scenarios.
abstract: Silicon (Si) has important functional roles in plants, including resistance against herbivores. Environmental change, such as increasing atmospheric concentrations of CO2, may alter allocation to Si defences in grasses, potentially changing the feeding behaviour and performance of herbivores, which may in turn impact on higher trophic groups. Using Si-treated and untreated grasses (Phalaris aquatica) maintained under ambient (400 ppm) and elevated (640 and 800 ppm) CO2concentrations, we show that Si reduced feeding by crickets (Acheta domesticus), resulting in smaller body mass. This, in turn, reduced predatory behaviour by praying mantids (Tenodera sinensis), which consequently performed worse. Despite elevated CO2decreasing Si concentrations inP. aquatica, this reduction was not large enough to affect the feeding behaviour of crickets or their predator. Our results suggest that Si-based defences in plants have adverse impacts on both primary and secondary trophic taxa, and these are not likely to decline under future climate change scenarios.
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Bourke Street, Richmond, New South Wales 2753, Australia j.ryalls@westernsydney.edu.au.
authors.forename: James M W
authors.identifier: 0000-0003-2015-3605
authors.initials: JM
authors.lastname: Ryalls
authors.affiliation: York Environmental Sustainability Institute, University of York, Wentworth Way, Heslington, York YO10 5DD, UK.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hartley
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Bourke Street, Richmond, New South Wales 2753, Australia.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001272:Atmosphere / Q000737:chemistry; D001835:Body Weight; D002245:Carbon Dioxide / Q000494:pharmacology*; D005247:Feeding Behavior; D020387:Food Chain; D006135:Gryllidae / Q000502:physiology*; D020050:Mantodea / Q000502:physiology*; D031783:Phalaris / Q000737:chemistry* / Q000187:drug effects; D011235:Predatory Behavior; D012825:Silicon / Q000032:analysis*
chemical_list: D002245:Carbon Dioxide; D012825:Silicon
keywords: climate change; insect herbivore; natural enemy; plant defence; predator; silicon