Role of host plant in determining the insect community associated with the flowers of dicotyledoneous herbaceous plants
Abstrakt
Flowers of dicotyledoneous plants usually host a rich community of insects consisting of herbivores, nectar and pollen feeders, carnivores seeking prey and occasional visitors. Taxonomic affiliation of the plants is an important factor determining the composition of this community but its effect is confounded by seasonality and geographic variation in the fauna of insect visitors.
To exclude these effects, we studied communities of flowers of 12 herbaceous plants at a single site over a period of 5 days during the flowering period. Whole flowers were harvested, the resident insects collected and identified to species.
Insect communities consisted of >50 insect species, mainly Coleoptera, Hymenoptera and Heteroptera. The most abundant species were Meligethes aeneus (Fabricius, 1775) and Byturus ochraceus (Scriba, 1790).
The most diverse communities were associated with flowers of Taraxacum agg., Geranium pratense and Crepis biennis. The similarity between the communities associated with particular species of flowers was low at the level of taxa (mean Sorensen index S=0.243) and individual frequency (mean Renkonen index Re=0.232).
The composition and diversity of the communities were not related to flower colour, size, duration of flowering or plant height. Taxonomic affiliation of plants is an important factor in determining the composition of the associated insect communities, which acts through different effective causes.