Current Research Activities: Most species interactions take place in site-specific networks of multiple coevolving species, and each coevolutionary interaction is likely shaping suites of traits, on both sides of the interaction. Therefore, the three major study systems include multiple plant- and insect species that form small interaction networks. In these networks, we study spatial patterns in plant signaling and insect preferences, and how these interactions are affected by the nature of the plant-insect relationship (antagonistic/mutualistic), and by the specificity of the interaction.
1. Floral scent evolution in ecological networks: The same signals that attract pollinators can be picked up also by herbivores and seed predators. Local variation in these networks is likely to be an important driver of geographical variation in plant signaling. We use several model systems, including different populations of the crucifer plants Arabis alpina and Arabidopsis lyrata. In these species, several populations have evolved self-compatibility. These populations also show substantial variation in floral morphology and chemical floral signaling, and provide interesting model systems for understanding the relationship between different floral signals, the plant mating system and the local community of associated insects. The studies are performed in collaboration with several Swedish and international researchers, including Prof. Jon Ågren and Dr. Per Toräng at the Department of Plant Ecology and Evolution, Uppsala University.
2. Evolution of host plant preferences: Whereas plant signals are partly shaped by the need to avoid attacks from insect antagonists, the fitness of phytophagous insects is largely a result of how well the female succeeds in finding suitable hosts for her offspring. We use two closely related butterflies (Pieris napi and Pieris rapae), at different levels of host specialization, to study the evolutionary potential of host plant preferences, and how these relate to female experience, plant growth form and the composition of the host plant community. We use repeatable and reliable bioassays to determine patterns of local adaptations in host plant use. The current project explores how local selection can affect female egg-laying preferences, and how this relate to the landscape-level land use in each area. In collaboration with Christopher Wheat (Stockholm University), we also try to link the female preference variation to the genomic region of importance for this behavioral trait.
3. Coevolutionary divergence in tight mutualisms: Obligate relationships between prodoxid moths and their host plants are among the best-studied examples of coevolution in nature. The moth Greya politella simultaneously pollinates and lays eggs into the flowers of its Lithophragma host plants (Saxifragaceae). In collaboration with collaborators in the US (John N Thompson and Robert A Raguso), and Brazil (Paulo Guimaraes JR), we study the evolution of floral scent variation, and its importance for interaction specificity and population and species divergence among both the plants and the insects. Further, we compare the impact of selection from the specific moth pollinators with the evolutionary effects of generalized co-pollinators at various geographic scales.