Colouration facilitates evolutionary investigations in nature because the interaction between genotype, phenotype and environment is relatively accessible. In a landmark set of studies, Endler addressed this complexity by demonstrating that the evolution of male Trinidadian guppy colouration is shaped by the local balance between selection for mate attractiveness versus crypsis. This became a textbook paradigm for how antagonistic selective pressures may determine evolutionary trajectories in the wild. Recent studies have, however, challenged the generality of this paradigm. Here we respond to these challenges by reviewing five important yet underappreciated factors that contribute to colour pattern evolution: (1) inter-population variation in female preference, (2) differences in how predators versus conspecifics view males, (3) biased assessment of pigmentary versus structural colouration, (4) the importance of accounting for multi-species predator communities, and (5) the importance of considering the multivariate genetic architecture and multivariate context of selection. We elaborate upon these points specifically in relation to two papers that illustrate the challenges raised by the recent body of work on guppies. More broadly, we emphasise the depth of consideration necessary for testing evolutionary hypotheses using complex multi-trait phenotypes such as guppy colour patterns.

For more detail, refer Notes.txt file.