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.