Orchids,bilateral symmetry and insect perception

The basic characteristics of orchids, possessing the greatest number of complex floral images of any Angiosperm family, are reviewed. Bilateral symmetry (zygomorphy) is shown by use of information theory techniques to give much greater possibilities for the transmission of visually mediated information than radial symmetry. The difference in information content is further enhanced by motion. The analysis is offered as evidence that the evolution of diversity in complex images, if effected by the unique behavioral specificity of pollinators known as “flower constancy”, is most economically explained by hypothesizing recognition and storage of the total image (“gestalt”) in the agents of natural selection.