Proximate mechanisms of alternative reproductive morphs

Alternative reproductive morphs contribute significantly to phenotypic diversity of populations. The Ruff is an iconic shorebird with three alternative mating tactics. The three morphs differ dramatically in their appearance and behaviour. Most Ruff males are aggressive fighters whose elite is meeting every spring in mating arenas to display for female, these are called Independents. By contrast, Satellites are non-aggressive displaying Ruffs that attempt sneaky copulations with females when the displaying Independents are distracted by conflicts. The third and rarest type is called Fæder. Faeders resemble females and actively distract Independents from mating by posing as another female ready to mate. They also sneak opportunistically copulations.  Somewhat unusual all these types of males are each fully genetically determined meaning the life strategy of a Ruff is sealed at conception already and there is also a female version for each morph. We recently described the underlying genomic sequence differences.

Taking this further, we are currently working on characterising the molecular pathways that lead to the dramatic phenotypic differences between morphs using transcriptomics and hormonal analyses. This has wider significance because the Ruff can provide a new vertebrate model system to understand the genetics of aggression.