Fitness components in the relationship between Rhopalapion longirostre (Olivier, 1807) (Insecta: Coleoptera: Apionidae) and Alcea rosea (Linnaeus, 1758) (Malvaceae). Analysis of infestation balance of a herbivorous weevil and its host plant

摘要

Multivariate statistics (principal components analysis, path analysis) were used to investigate fitness components of the interactions between the weevil Rhopalapion longirostre (Olivier, 1807), Apionidae, Coleoptera and its host plant Alcea rosea (Linnaeus, 1758), Malvaceae. We focused on the activities of the larvae such as the choice of seeds for consumption, the preparation of seed chambers as a site for pupation, as well as the construction of escape holes through which the adults later emerge.The analyses revealed that the optimal conditions for successful development of the weevils depended on the availability of seed capsules characterized by a high number of well developed seeds, few undeveloped and few spoiled seeds. The high number of larvae, pupae and not emerged adults found in the seed capsules corresponds with the successful emergence of adults. Egg deposition by the females in appropriate flower buds of the host plant, together with larval contribution to overall reproductive success are important fitness components in the life cycle of the weevil. The reproductive success of the plant is partly guaranteed by a high number of seed chambers, many well developed seeds, many not infested seeds, and few undeveloped seeds. Furthermore,the extended blooming period of the host plant serves as an escape strategy by developing buds early or late in the season that cannot become entangled in the life cycle of R. longirostre.