Molecular basis and evolution of visual mate recognition in Heliconius butterflies

• Applicant: Professor Richard Merrill, Ph.D.
• Subject Area: Sensory and Behavioural Biology ; Evolution, Anthropology
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 324604099

Adaptation to different ecological niches can result in the evolution of new species, and a major goal of evolutionary biology is to identify the genetic changes underlying population divergence. Relative to morphological traits, the genetics of behavioural differences observed in nature have not been well characterized. This is especially true for behaviours that contribute to reproductive isolation. However, these behaviours, such as assortative mate preferences, are known to evolve rapidly during population divergence and are important during the evolution of new species. The Heliconius butterflies are one of only a few systems in which it will be possible to fully dissect the genetics and evolutionary history of mate recognition behaviours within their ecological context. This Neotropical genus is well known for its bright warning patterns, and has been especially well studied with respect to adaptation and speciation. Distantly related species often use the same warning pattern due to selection for mimicry. However, closely related species can look very different and non-mimetic hybrids, which are not recognized as distasteful, suffer increased predation. Shifts in colour pattern also result in behavioural isolation as males show a preference for their own wing pattern over that of closely related species. However, while the genetics of warning pattern are now known in fantastic detail, our understanding of the corresponding behaviours at the molecular level remains limited. My research aims to identify the causal genes underlying visual mate recognition in Heliconius butterflies. I will first develop novel methods to efficiently and accurately quantify visual attraction. By combining modern molecular techniques with accurate behavioural data for a large mapping population, I will identify narrow genomic regions underlying differences in visual attraction. These analyses will be conducted between ecologically divergent species that are sympatric, and then between species which are not in contact. This will test a key hypothesis of speciation research that loci controlling behavioural and ecological traits that cause reproductive isolation between populations that remain in contact are clustered in the genome. Identifying the candidate regions in multiple species pairs will also facilitate genomic analyses to further key in on the genetic basis of visual attraction. I will combine these analyses with expression studies with the ultimate goal of providing candidates for functional experiments. This work will offer new insights into speciation, a process fundamental to evolution and biodiversity, but also has wider implications for our understanding of the genetics of ecologically relevant behaviours.

• DFG Programme: Independent Junior Research Groups