Adaptation as a spatiotemporal mosaic of natural and sexual selection

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My research seeks to understand how biological diversity originates and evolves when subjected to environmental variation. An important source of biological diversity is thought to be natural selection that causes adaptation to different environments, which then leads to new species. In addition, recent work has shown that sexual selection (traits that increase mating success) is also important in this process. In Trinidadian guppies, females are thought to favour brightly coloured males (sexual selection) but this makes them more susceptible to being predated upon by a predator (natural selection). Spatial variation in natural selection (different predation levels) drives divergence: males are more brightly coloured in low-predation sites and vice-versa. However, recent work suggests the strength and direction of natural and sexual selection can vary through time and between populations. Thus, my project investigates the underlying causes of this spatial and temporal variation in selection. To explore this, I am quantifying spatial and temporal variation in guppy colour patterns by analyzing digital photos. I have collected environmental data to tease apart potential determinants for this variation in colour. I have also started a large scale lab experiment to see if I can 'drive' expected alternative evolutionary trajectories by imposing different patterns of natural and sexual selection, and I will quantify natural and sexual selection on guppy colour in the wild. In Canada, our ecosystems are subject to a variety of human disturbances and natural pressures resulting in environmental change. Understanding the underlying causes of variation in selection will help predict how natural populations will respond to this ongoing change. For example, my work can help predict what might happen to native fauna when foreign species are introduced, and this can inform conservation and management policies.