title: Overcompensation of herbivore reproduction through hyper-suppression of plant defenses in response to competition.
abstract: Spider mites are destructive arthropod pests on many crops. The generalist herbivorous mite Tetranychus urticae induces defenses in tomato (Solanum lycopersicum) and this constrains its fitness. By contrast, the Solanaceae-specialist Tetranychus evansi maintains a high reproductive performance by suppressing tomato defenses. Tetranychus evansi outcompetes T. urticae when infesting the same plant, but it is unknown whether this is facilitated by the defenses of the plant. We assessed the extent to which a secondary infestation by a competitor affects local plant defense responses (phytohormones and defense genes), mite gene expression and mite performance. We observed that T. evansi switches to hyper-suppression of defenses after its tomato host is also invaded by its natural competitor T. urticae. Jasmonate (JA) and salicylate (SA) defenses were suppressed more strongly, albeit only locally at the feeding site of T. evansi, upon introduction of T. urticae to the infested leaflet. The hyper-suppression of defenses coincided with increased expression of T. evansi genes coding for salivary defense-suppressing effector proteins and was paralleled by an increased reproductive performance. Together, these observations suggest that T. evansi overcompensates its reproduction through hyper-suppression of plant defenses in response to nearby competitors. We hypothesize that the competitor-induced overcompensation promotes competitive population growth of T. evansi on tomato.
authors.affiliation: Department of Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Bernardus C J
authors.initials: BCJ
authors.lastname: Schimmel
authors.affiliation: Department of Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands.|Department of Entomology, Federal University of Viçosa, CEP 36570-000, Viçosa, Brazil.
authors.forename: Livia M S
authors.initials: LMS
authors.lastname: Ataide
authors.affiliation: Department of Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Rachid
authors.initials: R
authors.lastname: Chafi
authors.affiliation: Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, PO Box 94215, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Villarroel
authors.affiliation: Department of Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Juan M
authors.identifier: http://orcid.org/0000-0003-4822-9827
authors.initials: JM
authors.lastname: Alba
authors.affiliation: Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, PO Box 94215, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Schuurink
authors.affiliation: Department of Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands.
authors.forename: Merijn R
authors.initials: MR
authors.lastname: Kant
mesh_terms: D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism; D005260:Female; D018506:Gene Expression Regulation, Plant; D060434:Herbivory; D018551:Solanum lycopersicum / Q000502:physiology*; D008297:Male; D054883:Oxylipins / Q000378:metabolism; D027805:Phaseolus / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000502:physiology; D020156:Salicylic Acid / Q000378:metabolism; D040102:Tetranychidae / Q000235:genetics / Q000502:physiology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; D020156:Salicylic Acid
keywords: 
  Tetranychus evansi
  ; 
  Tetranychus urticae
  ; competition; defense suppression; overcompensation; plant-mediated interactions; spider mites; tomato (Solanum lycopersicum)