Different pollinator groups (bees, ants, wasps, flies, beetles and butterflies) preferentially visit flowers of certain colours. Interestingly, these colour preferences match the predictions of the pollination syndrome theory. However, flowers with similar colours do not attract similar pollinator assemblages. This is due to the fact that most flower species are pollinator generalist.
Reverté et al. conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations.
Sara Reverté, Javier Retana, José M. Gómez, Jordi Bosch, 2016, 'Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators', Annals of Botany, vol. 118, no. 2, pp. 249-257 http://dx.doi.org/10.1093/aob/mcw103