INSECT PREFERENCE FOR SYMMETRICAL ARTIFICIAL FLOWERS

An insect preference for floral symmetry may be maintained because pla nts with symmetrical flowers, which are able to control developmental processes under given environmental conditions, also are able to provi de more pollinator rewards than plants with asymmetrical flowers. Alte rnatively, insects may have an inherent preference for symmetrical str uctures and thereby impose selection for the maintenance of symmetry i n flowers even in the absence of any pollinator rewards. We tested for an insect preference for radially symmetrical flowers by using horizo ntally placed units of four circular coloured flower models varying in size and symmetry. The shape and colour of the model flowers did not resemble any naturally occurring flowers in the environment. Insects a nd Hymenoptera, respectively (five species of Diptera and one species of Coleoptera) that visited the flower models clearly preferred symmet rical models over asymmetrical ones, and the ranking of visits to the models reflected a preference for large symmetrical flowers. These res ults provide evidence for a preference for symmetrical flower models, even in the absence of pollinator rewards.