Domatia reduce larval cannibalism in predatory mites

Abstract

Abstract1. Acarodomatia are small structures on the underside of leaves of many plant species, which are mainly inhabited by carnivorous and fungivorous mites.2. Domatia are thought to protect these mites against adverse environmental conditions and against predation. They are considered as an indirect plant defence; they provide shelter to predators and fungivores and these in turn protect the plants against herbivores and fungi.3. We studied the possible role of domatia of coffee (Coffea arabicaL.) (Rubiaceae) and sweet pepper (Capsicum annumL.) (Solanaceae) in reducing cannibalism in the mites inhabiting the domatia. We measured cannibalism of larvae by adults of the predatory mitesIphiseiodes zuluagaiDenmark & Muma andAmblyseius herbicolusChant on coffee leaf discs and of the predatory miteIphiseius degenerans(Berl.) on sweet pepper leaf. Domatia were closed with glue or left open.4. Cannibalism in all three species increased when domatia were closed. WithI. degenerans, moreover, we found that the previous diet of the cannibal attenuated the effect of domatia on cannibalism.5. We conclude that domatia can protect young predatory mites against cannibalism by adults and that the diet of cannibals affects the rate of cannibalism.