The evolution and maintenance of species diversity relies on barriers to gene exchange between populations. Although these barriers can take several forms, many closely related animals remain separate not because they fail to produce viable offspring, but because they ‘choose’ not to mate in the first place. Our project aims to understand how and why these behavioural barriers emerge, both during development and across evolutionary time.
We study the genetics, brains and behaviours of South American Heliconius butterflies. Importantly, past Heliconius research provides a robust ecological framework. In particular, Heliconius have bright warning patterns, which differ between populations, and which are used by males to recognise females of their own species. Heliconius species also differ in habitat use, and we predict that both these ecological axes drive adaptation in the sensory systems and brain.
Establishing the links across ecological, genetic and neural changes is crucial to our understanding of how behaviours, and the sensory systems through which they are mediated, adapt and ultimately contribute to speciation. To do this our project has four major objectives.
1) Characterise how the components of behavioural isolation vary with ecology. We are collecting data on i) different components of the nervous system, ii) mating signals, and iii) behaviours across populations to determine how these vary with major environmental transitions.
2) Assess the role of selection in shaping the sensory periphery and the brain. We are collecting data on components of the nervous system from hybrids to test i) whether the differences we observe across ecological transitions are the result of natural selection, and ii) whether these differences directly relate to changes in sensitivity and integration of visual and olfactory stimuli.
3) Determine the genomic architecture of behavioural isolation. In combination with DNA sequencing, our hybrid data will allow us to ask which regions of the genome contribute to differences in both the nervous system and mate choice behaviours.
4) Link behaviours to the action of individual genes. By combining data from the previous three objectives we hope to identify candidate genes underlying changes in behaviour, which we can target with state-of-the-art genome editing techniques. The ultimate aim is to link genes to behaviour, and the sensory systems through which they are mediated.
