Abstract

Grasslands cover almost a quarter of the Earth’s surface and provide food for us, our livestock and natural populations of grazing animals. Thus understanding interactions between grasses and their herbivores is central to the conservation of grasslands rich in biodiversity and to our future food security – almost half the world’s calories come from maize, wheat and rice and ~20% of the crop is currently lost to pests. But grasses are not completely defenceless – they accumulate silicon (Si), a sharp abrasive substance, in their leaves. This talk will illustrate how and why Si is an effective anti-herbivore defence in grasses, its potential impact on herbivore populations and how it could be useful in sustainable methods of crop protection in future. High levels of Si make grasses more unpalatable, reduce the ability of herbivores to digest the grass and extract essential nutrients from it and can even affect herbivore abundance, but grass species differ in their allocation to Si defences, and in the extent to which they respond to herbivore attack by increasing the levels of these defences. Interestingly, modern crop cultivars use Si defences differently, and potentially less effectively, when compared with ancestral varieties.

Everyone is welcome. Free for members, £2 on the door for non-members. Followed by refreshments (that means smoothies, cheese and grapes!).