Why stay in a bad relationship? The effect of local host phenology on a generalist butterfly feeding on a low-ranked host
(English)Manuscript (preprint) (Other academic)
In plant-feeding insects, a better understanding of the relationship between the organisms and the metabolome of their host plants is likely to suggest functional links between them, and may provide insights into how polyphagy is maintained. To address this question, we investigated the phenological change of Cynoglossum officinale, and how a generalist butterfly species, Vanessa cardui, responded to this change. We used untargeted metabolite profiling to map plant seasonal changes in both primary and secondary metabolites. We compared this data to differences in larval performance on vegetative plants early and late in the season. We also performed two oviposition preference experiments to test females’ ability to choose between plant developmental stages (vegetative and reproductive) early and late in the season. We found clear seasonal changes in plant primary and secondary metabolites that correlated with larval performance. The seasonal change in plant metabolome reflected changes in both nutrition and toxicity and resulted in a zero survival in the late period. However, large differences among families in larval ability to feed on C. officinale suggest that there is genetic variation for performance on this host. Moreover, females accepted all plants for oviposition, and were not able to discriminate between plant developmental stages, in spite of their observed overall differences in metabolite profile potentially associated with differences in suitability as larval food. In V. cardui, migratory behavior is not synchronized with the plant phenology at the reproductive site. The observed lack of discriminatory oviposition behavior will therefore likely add-up to the lack of synchronization that may occur between larval feeding time and plant phenology. This lack of synchronization has obvious fitness cost. However, this “opportunistic” behavior may as well function as a source of potential host plant evolution, promoting for example the acceptance of new plants.
Vanessa cardui, larval performance, oviposition choice, metabolomics, primary metabolites, secondary metabolites, GC-MS, LC-MS
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:su:diva-119718OAI: oai:DiVA.org:su-119718DiVA: diva2:848004