Experimental demonstration of the antiherbivore effects of silica in grasses: impacts on foliage digestibility and vole growth rates

Massey, F. P. and Hartley, S. E. (2006) Experimental demonstration of the antiherbivore effects of silica in grasses: impacts on foliage digestibility and vole growth rates. Proceedings B: Biological Sciences, 273 (1599). pp. 2299-2304. ISSN 1471-2954

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Abstract

The impact of plant-based factors on the population dynamics of mammalian herbivores has been the subject of much debate in ecology, but the role of antiherbivore defences in grasses has received relatively little attention. Silica has been proposed as the primary defence in grasses and is thought to lead to increased abrasiveness of foliage so deterring feeding, as well as reducing foliage digestibility and herbivore performance. However, at present there is little direct experimental evidence to support these ideas. In this study, we tested the effects of manipulating silica levels on the abrasiveness of grasses and on the feeding preference and growth performance of field voles, specialist grass-feeding herbivores. Elevated silica levels did increase the abrasiveness of grasses and deterred feeding by voles. We also demonstrated, for the first time, that silica reduced the growth rates of both juvenile and mature female voles by reducing the nitrogen they could absorb from the foliage. Furthermore, we found that vole feeding leads to increased levels of silica in leaves, suggesting a dynamic feedback between grasses and their herbivores. We propose that silica induction due to vole grazing reduces vole performance and hence could contribute to cyclic dynamics in vole populations.

Item Type: Article
Keywords: Animals Arvicolinae/ growth & development Digestion/ physiology Feeding Behavior/physiology Female Festuca/chemistry/ metabolism Food Preferences Lolium/chemistry/ metabolism Research Support, Non-U.S. Gov't Silicon Dioxide/analysis/ metabolism
Schools and Departments: School of Life Sciences > Biology and Environmental Science
Subjects: Q Science > QH Natural history > QH0301 Biology
Depositing User: Susan Hartley
Date Deposited: 28 Nov 2006
Last Modified: 07 Mar 2017 09:00
URI: http://sro.sussex.ac.uk/id/eprint/581
Google Scholar:35 Citations

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