title: Simultaneous inbreeding modifies inbreeding depression in a plant-herbivore interaction.
abstract: Because inbreeding is common in natural populations of plants and their herbivores, herbivore-induced selection on plants, and vice versa, may be significantly modified by inbreeding and inbreeding depression. In a feeding assay with inbred and outbred lines of both the perennial herb, Vincetoxicum hirundinaria, and its specialist herbivore, Abrostola asclepiadis, we discovered that plant inbreeding increased inbreeding depression in herbivore performance in some populations. The effect of inbreeding on plant resistance varied among plant and herbivore populations. The among-population variation is likely to be driven by variation in plant secondary compounds across populations. In addition, inbreeding depression in plant resistance was substantial when herbivores were outbred, but diminished when herbivores were inbred. These findings demonstrate that in plant-herbivore interactions expression of inbreeding depression can depend on the level of inbreeding of the interacting species. Furthermore, our results suggest that when herbivores are inbred, herbivore-induced selection against self-fertilisation in plants may diminish.
authors.affiliation: Section of Ecology, University of Turku, Turku, Finland.
authors.forename: Aino
authors.initials: A
authors.lastname: Kalske
authors.forename: Pia
authors.initials: P
authors.lastname: Mutikainen
authors.forename: Anne
authors.initials: A
authors.lastname: Muola
authors.forename: J F
authors.initials: JF
authors.lastname: Scheepens
authors.forename: Liisa
authors.initials: L
authors.lastname: Laukkanen
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Salminen
authors.forename: Roosa
authors.initials: R
authors.lastname: Leimu
mesh_terms: D000818:Animals; D029062:Apocynaceae / Q000235:genetics* / Q000378:metabolism; D005260:Female; D060434:Herbivory; D007178:Inbreeding; D008297:Male; D009036:Moths / Q000235:genetics*; D064210:Secondary Metabolism; D012641:Selection, Genetic
keywords: Abrostola asclepiadis; Vincetoxicum hirundinaria; experimental inbreeding; insect herbivory; performance; phenolic compounds; plant mating system; resistance; secondary chemistry; self-fertilisation