a herbivorous mite down-regulates plant defence and produces web to exclude competitors食草螨下调植物防御和生产网络排除竞争对手.pdfVIP

A Herbivorous Mite Down-Regulates Plant Defence and Produces Web to Exclude Competitors 1,2 3 3 1 1 Renato A. Sarmento , Felipe Lemos , Cleide R. Dias , Wagner T. Kikuchi , Jean C. P. Rodrigues , Angelo 3 2 2 Pallini , Maurice W. Sabelis , Arne Janssen * 1 Graduate Programme in Plant Science, Federal University of Tocantins (UFT), Gurupi, Tocantins, Brazil, 2 Section Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands, 3 Department of Entomology, Federal University of Vic¸osa, Vic¸osa, Brazil Abstract Herbivores may interact with each other through resource competition, but also through their impact on plant defence. We recently found that the spider mite Tetranychus evansi down-regulates plant defences in tomato plants, resulting in higher rates of oviposition and population growth on previously attacked than on unattacked leaves. The danger of such down- regulation is that attacked plants could become a more profitable resource for heterospecific competitors, such as the two- spotted spider mite Tetranychus urticae. Indeed, T. urticae had an almost 2-fold higher rate of oviposition on leaf discs on which T. evansi had fed previously. In contrast, induction of direct plant defences by T. urticae resulted in decreased oviposition by T. evansi. Hence, both herbivores affect each other through induced plant responses. However, when populations of T. evansi and T. urticae competed on the same plants, populations of the latter invariably went extinct, whereas T. evansi was not significantly affected by the presence of its competitor. This sugg