title: Down-regulation of plant defence in a resident spider mite species and its effect upon con- and heterospecifics.
abstract: Herbivorous spider mites occurring on tomato plants (Solanum lycopersicum L.) cope with plant defences in various manners: the invasive Tetranychus evansi reduces defences below constitutive levels, whereas several strains of T. urticae induce such defences and others suppress them. In the Mediterranean region, these two species co-occur on tomato plants with T. ludeni, another closely related spider mite species. Unravelling how this third mite species affects plant defences is thus fundamental to understanding the outcome of herbivore interactions in this system. To test the effect of T. ludeni on tomato plant defences, we measured (1) the activity of proteinase inhibitors, indicating the induction of plant defences, in those plants, and (2) mite performance on plants previously infested with each mite species. We show that the performance of T. evansi and T. ludeni on plants previously infested with T. ludeni or T. evansi was better than on clean plants, indicating that these two mite species down-regulate plant defences. We also show that plants attacked by these mite species had lower activity of proteinase inhibitors than clean plants, whereas herbivory by T. urticae increased the activity of these proteins and resulted in reduced spider mite performance. This study thus shows that the property of down-regulation of plant defences below constitutive levels also occurs in T. ludeni.
authors.affiliation: cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal. diogoprinogodinho@hotmail.com.
authors.forename: Diogo P
authors.initials: DP
authors.lastname: Godinho
authors.affiliation: Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Arne
authors.initials: A
authors.lastname: Janssen
authors.affiliation: cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Dias
authors.affiliation: cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cruz
authors.affiliation: cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal. snmagalhaes@fc.ul.pt.
authors.forename: Sara
authors.initials: S
authors.lastname: Magalhães
mesh_terms: D000818:Animals; D060467:Disease Resistance; D015536:Down-Regulation; D060434:Herbivory; D018551:Solanum lycopersicum / Q000378:metabolism / Q000502:physiology*; D019083:Mediterranean Region; D008925:Mites / Q000502:physiology; D010935:Plant Diseases; D011480:Protease Inhibitors / Q000378:metabolism; D013045:Species Specificity; D040102:Tetranychidae / Q000502:physiology*
chemical_list: D011480:Protease Inhibitors
keywords: Plant defences; Plant–herbivore interactions; Proteinase inhibitors; Spider mites; Tetranychus ludeni