Silicon as a plant defence against insect herbivory: response to Massey, Ennos and Hartley
Article first published online: 13 MAR 2008
© 2008 The Authors
Journal of Animal Ecology
Volume 77, Issue 3, pages 631–633, May 2008
How to Cite
Keeping, M. G. and Kvedaras, O. L. (2008), Silicon as a plant defence against insect herbivory: response to Massey, Ennos and Hartley. Journal of Animal Ecology, 77: 631–633. doi: 10.1111/j.1365-2656.2008.01380.x
- Issue published online: 13 MAR 2008
- Article first published online: 13 MAR 2008
- Received 27 June 2007; accepted 11 January 2008; Handling Editor: Charles Godfray
- biotic stressors;
- herbivore performance;
- induced defence;
- mechanical barrier;
- plant resistance
- 1Silicon (Si) has received increased attention as a nutrient capable of providing some measure of defence for plants against fungal pathogens, and insect and mammalian herbivores.
- 2On the basis of a study including two generalist insect folivores and a phloem feeder, Massey, Ennos & Hartley (2006; Journal of Animal Ecology, 75, 595–603) have drawn attention to a putative distinction between the effects of plant Si in defending against folivorous and phloem-feeding insects. On the basis of their results they imply that phloem feeders are less likely to be adversely affected by increased plant Si than folivores.
- 3However, in making this suggestion, Massey et al. have ignored many previous studies demonstrating a clear effect of plant Si on a range of phloem-feeding and some xylem-feeding insects, and that this effect stems not only from leaf mechanical properties based on opaline silica, but also from induced chemical defences seemingly mediated by soluble Si.
- 4Furthermore, Massey et al. cannot claim that their study was the first demonstration of a direct effect of Si on insect herbivore preference and performance; there have been numerous earlier studies demonstrating this from folivores, stem borers, and phloem and xylem feeders.
- 5We contend that current evidence indicates that Si is likely to be involved to a similar extent in enhancing resistance to all four insect feeding guilds and that any conclusion to the contrary is, at this stage, premature.