Doctoral position - Evolutionary genomics of visual behaviours in Heliconius butterflies

Department/Institute: LMU Faculty of Biology, Evolutionary Biology

Subject areas/Research fields: Evolutionary Biology, Genetics, Animal Biology & Ethology 

Keywords: Speciation, Heliconius, Mate choice, Behaviour, Sensory ecology 

Name of supervisor: Prof. Dr. Richard Merrill

Project title: Evolutionary genomics of visual behaviours in Heliconius butterflies

Project description:

We are looking for a PhD student to investigate the evolutionary genomics of sensory and behavioural adaptations during species divergence in tropical Heliconius butterflies. 

Heliconius butterflies are well known for their diversity of bright warning patterns, which are also used as mating cues. Closely related taxa often display divergent wing patterns, and because males almost invariably prefer to court females that share their own colour pattern, this contributes an important premating reproductive barrier between species. While the genetics and evolutionary history of Heliconius colour pattern variation is well understood, we know less about the genomic basis of the mechanisms contributing to the evolution of the corresponding visual preference behaviours. Recently we have identified a major effect gene influencing visual preference differences between the sympatric species H. melpomene and H. cydno (see Rossi et al. Science 2024). Following up on this work, the student could take a number of different directions, combining approaches from evolutionary genomics and sensory/behavioural ecology.

One project would be to determine the genetic basis of visual preferences under different selection regimes (specifically under scenarios where reinforcement selection is and is not a likely evolutionary force), as well as the extent to which adaptive introgression of preference alleles across the wider genome contributes to behavioural evolution. The student could alternatively (or in addition) explore the nature of the specific cues involved and how this influences divergence, and how visual and olfactory preferences interact at genetic and phenotypic levels. 

Another direction would be to assess the genetic basis of visual preferences in another pair of Heliconius species, distantly related from H. melpomene and H. cydno. We know that colour pattern differences are controlled by the same genes (but different mutations) across the Heliconius genus. Is there a similar genomic ‘predictability’ underlying behavioural evolution? In addition, in the cydno-melpomene group, a major preference locus is physically linked to one of these major colour pattern genes, which may facilitate speciation (Merrill et al. PLoS Biology 2019). We would like to know if such linkage also exists for other species pairs (i.e. is there convergent genetic architecture), and if this is the case, ultimately whether this is due to the co-option of the same genes. 

Other projects on the genetics of sensory adaptations in Heliconius butterflies, and especially the genetic basis of shifts in neural investment associated with ecology, are also possible. Projects could involve a number of different techniques, including (but not limited to): behavioural assays, linkage mapping, gene expression and population genomic analyses and CRIPR/Cas9 genome editing. Potential students should contact Richard Merrill (merrill@bio.lmu.de) to discuss projects.

References:

Rossi, M., Hausmann, A.E., Alcami, P., Möst, M., Wright, D.S., Kuo, C.-Y., Lozano-Urrego, D., Maulana, A., Melo-Flórez, L., Rueda-Muñoz G., McMahon, S., Linares, M., McMillan, O., Pardo-Diaz, C., Salazar, C. & Merrill, R.M. (2024) Adaptive introgression of a visual preference gene. Science 383: 1368-1378

Merrill R.M., Rastas P., Martin S.H., Melo, M.C., Barker S., Davey, J., McMillan W.O., Jiggins, C. (2019) Genetic dissection of assortative mating behavior. PLoS Biology 17: e2005902

Montgomery, S.H., Rossi, M., McMillan, O. & Merrill, R.M. (2021) Neural divergence and hybrid disruption between ecologically isolated Heliconius butterflies. PNAS 116: e2015102118

Wright, D.S., Rodriguez-Fuentes, J., Ammer, L., Darragh, K., Kyu, C-Y., McMillan, W.O., Jiggins, C., Montgomery, S. & Merrill, R.M. (2024) Selection drives divergence of eye morphology in sympatric Heliconius butterflies Evolution 78: 1338-1348

For further information, please contact: Richard Merrill merrill@bio.lmu.de

Research group website: https://www.evol.bio.lmu.de/research/merrill/index.html

Apply: Please send your application through the online portal of the Graduate School Life Science Munich (LSM)