title: Preference for outbred host plants and positive effects of inbreeding on egg survival in a specialist herbivore.
abstract: Inbreeding can profoundly affect the interactions of plants with herbivores as well as with the natural enemies of the herbivores. We studied how plant inbreeding affects herbivore oviposition preference, and whether inbreeding of both plants and herbivores alters the probability of predation or parasitism of herbivore eggs. In a laboratory preference test with the specialist herbivore moth Abrostola asclepiadis and inbred and outbred Vincetoxicum hirundinaria plants, we discovered that herbivores preferred to oviposit on outbred plants. A field experiment with inbred and outbred plants that bore inbred or outbred herbivore eggs revealed that the eggs of the outbred herbivores were more likely to be lost by predation, parasitism or plant hypersensitive responses than inbred eggs. This difference did not lead to differences in the realized fecundity as the number of hatched larvae did not differ between inbred and outbred herbivores. Thus, the strength of inbreeding depression in herbivores decreases when their natural enemies are involved. Plant inbreeding did not alter the attraction of natural enemies of the eggs. We conclude that inbreeding can significantly alter the interactions of plants and herbivores at different life-history stages, and that some of these alterations are mediated by the natural enemies of the herbivores.
authors.affiliation: Section of Ecology, University of Turku, FI-20014 Turku, Finland aino.kalske@utu.fi.
authors.forename: Aino
authors.initials: A
authors.lastname: Kalske
authors.affiliation: Section of Ecology, University of Turku, FI-20014 Turku, Finland Department of Ecology, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden.
authors.forename: Anne
authors.initials: A
authors.lastname: Muola
authors.affiliation: Institute of Integrative Biology, ETH-Zürich, ETH-Zentrum, CH-8092 Zürich, Switzerland.
authors.forename: Pia
authors.initials: P
authors.lastname: Mutikainen
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK.
authors.forename: Roosa
authors.initials: R
authors.lastname: Leimu
mesh_terms: D000818:Animals; D005260:Female; D060434:Herbivory; D007178:Inbreeding; D009036:Moths / Q000502:physiology*; D010058:Oviposition; D066047:Vincetoxicum / Q000502:physiology*
keywords: Abrostola asclepiadis; Vincetoxicum hirundinaria; experimental inbreeding; insect herbivory; natural enemies; oviposition