When mother does not know best: Contrasting host plant choice across life stages in individuals of the comma butterfly
(English)Manuscript (preprint) (Other academic)
Since host plant choice is often crucial for the fitness of herbivorous insects we investigated if individual variation in such decisions is consistent throughout life. In the comma butterfly, Polygonia c-album, (Nymphalidae, Nymphalini) newly hatched larvae and adult females have been found to rank hosts plants similarly, suggesting that the host plant recognition mechanisms could be preserved through metamorphosis.
We measured preference for Urtica dioica relative to Salix cinerea when the plants were encountered by the same individuals in the two different life stages, finding no relationship between the two measurements. This was however found when we instead measured acceptance of a suboptimal host: First instar larvae were placed on the suboptimal S. cinerea, and were scored as to whether they accepted this host or if they instead moved to feed on the generally more preferred host U. dioica. The same individuals were then tested once more as ovipositing females, in a cage setup arranged so that females would encounter the low-ranked hosts S. cinerea and Betula pubescens more often than the high-ranked host U. dioica.
Individuals that chose to abandon S. cinerea as larvae differed in oviposition behaviour later in life from those that accepted this low-ranked host, but did so by laying a higher proportion eggs on the low-ranked hosts as adults. We interpret this initially unexpected result as a result of possible genetic correlation between female host-plant specificity and larval acceptance for the plant chosen by their mother: Offspring of ‘choosy’ specialist mothers have a strong tendency to remain on their original host, whereas less discriminating generalist mothers beget larvae with lower acceptance for their original plant when it is suboptimal. Ecologically, this presents a further explanation for how a generalist oviposition strategy can be sustained since larval mobility to some extent compensates for poor female choice.
insect-plant interactions, host plant choice, life-history, preference-performance correlations, personality, behavioural syndrome
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:su:diva-68074OAI: oai:DiVA.org:su-68074DiVA: diva2:471760