Why sensory ecology needs to become more evolutionary - insect color vision as a case in point.

Abstract

Many of the subtleties in the evolutionary tuning of sensory systems still escape us. Insect color vision is a typical case. While we know much about its mechanisms, the abundant adaptive explanations of its components are often ornate speculations. We advocate using an evolutionary approach to understand why different animals see the world in different colors. Such an approach must include (1) phylogenetic analyses, which should help identify patterns of adaptation, constraint and history; (2) molecular studies, to predict how plastic the relevant genes will be in the face of particular selective pressures; (3) assessments of interindividual variance, to see if the raw material for evolution exists; (4) a consideration of pleiotropic effects, where selection on visual pigments may be affected indirectly through correlated characters; (5) biogeography, to explore if populations living in different visual habitats have adapted to those differences; (6) a consideration of random evolutionary processes; (7) selection experiments, to test for heritability of traits and to simulate the influences of strong directional selection; (8) fitness tests: to show that a trait is adaptive, we must show empirically that this trait confers greater fitness to its bearers, compared with conspecifics which lack this trait.