title: Breaking and entering: predators invade the shelter of their prey and gain protection.
abstract: Many herbivorous arthropods construct shelters on their host plant that offer protection against natural enemies. This has resulted in selection on natural enemies to enter these shelters, where they can feed on prey that are inaccessible for competing predators and parasitoids. The spider mite Tetranychus evansi produces a shelter consisting of a dense web that is impenetrable for most predators; the only known natural enemy that can penetrate the web and can forage efficiently on this pest is Phytoseiulus longipes. We show that this predator preferentially foraged and oviposited in the web of its prey. Moreover, intraguild predation on juveniles of these predators was significantly higher outside this web and in the less dense web of a closely related prey species (T. urticae) than inside the web of T. evansi. Although the production of shelters by herbivores may be profitable at first, their adapted natural enemies may reap the benefit in the end.
authors.affiliation: IBED, Section Population Biology, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Felipe
authors.initials: F
authors.lastname: Lemos
authors.forename: Ana Maria Guimarães
authors.initials: AM
authors.lastname: Bernardo
authors.forename: Cleide Rosa
authors.initials: CR
authors.lastname: Dias
authors.forename: Renato Almeida
authors.initials: RA
authors.lastname: Sarmento
authors.forename: Angelo
authors.initials: A
authors.lastname: Pallini
authors.forename: Madelaine
authors.initials: M
authors.lastname: Venzon
authors.forename: Arne
authors.initials: A
authors.lastname: Janssen
mesh_terms: D000818:Animals; D020387:Food Chain; D060434:Herbivory; D018551:Solanum lycopersicum / Q000254:growth & development; D008925:Mites / Q000502:physiology*; D011235:Predatory Behavior; D040102:Tetranychidae / Q000502:physiology