title: Plant-herbivore synchrony and selection on plant flowering phenology.
abstract: Temporal variation in natural selection has profound effects on the evolutionary trajectories of populations. One potential source of variation in selection is that differences in thermal reaction norms and temperature influence the relative phenology of interacting species. We manipulated the phenology of the butterfly herbivore Anthocharis cardamines relative to genetically identical populations of its host plant, Cardamine pratensis, and examined the effects on butterfly preferences and selection acting on the host plant. We found that butterflies preferred plants at an intermediate flowering stage, regardless of the timing of butterfly flight relative to flowering onset of the population. Consequently, the probability that plant genotypes differing in timing of flowering should experience a butterfly attack depended strongly on relative phenology. These results suggest that differences in spring temperature influence the direction of herbivore-mediated selection on flowering phenology, and that climatic conditions can influence natural selection also when phenotypic preferences remain constant.
authors.affiliation: Department of Ecology, Environment and Plant Science, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: Elsa
authors.initials: E
authors.lastname: Fogelström
authors.affiliation: Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Olofsson
authors.affiliation: Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: Diana
authors.initials: D
authors.lastname: Posledovich
authors.affiliation: Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Wiklund
authors.affiliation: Department of Biology, Max-Planck Odense Center on the Biodemography of Aging, University of Southern Denmark, Campusvej 55, SE-106 91, Odense M, Denmark.
authors.forename: Johan P
authors.initials: JP
authors.lastname: Dahlgren
authors.affiliation: Department of Ecology, Environment and Plant Science, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Ehrlén
mesh_terms: D000818:Animals; D002080:Butterflies / Q000033:anatomy & histology* / Q000502:physiology; D031217:Cardamine / Q000502:physiology*; D060434:Herbivory; D010641:Phenotype; D010944:Plants; D012098:Reproduction
keywords: 
  Anthocharis cardamines
  ; 
  Cardamine pratensis
  ; herbivore preference; natural selection; reaction norm; trophic interaction