The more it changes, the more it stays the same: can phenotypic plasticity of the host counter parasite diversification? (R-12081)

Species diversity is unevenly spread: some lineages are highly species-rich, others are not. Though speciation research focuses on the former, understanding why lineages fail to diverge is crucial too. Parasites typically speciate faster than hosts, especially large and long-lived hosts, and become more species-rich. The research team found that all African lates perches, some of the largest freshwater fishes, host only a single monogenean flatworm: Dolicirroplectanum lacustre. I will further investigate this pattern to reveal phenotypic and genomic mechanisms underlying failure to diverge. I hypothesise that variability of a wide range of inland water habitats amplified by constraints on the host gills, forces D. lacustre into phenotypic plasticity preventing diversification. I will test this by contrasting morphological, physiological and genomic variability of host populations with those of the parasites. African lates perches' closest relatives occur in Indo-Pacific environments with more predictable conditions than in freshwater. These marine congeners harbour more monogenean species, presumably a result of a more stable environment. My comprehensive sample design, based on historical collections, therefore includes Indo-Pacific host and parasite congeners for comparison. Understanding an unexpected lack of diversification by integrating morphological, physiological and genomic diversity of hosts and their less species-rich parasite is a novel approach to speciation.

Keywords:BIODIVERSITY

Disciplines:Computational evolutionary biology, comparative genomics and population genomics, Phylogeny and comparative analysis, Speciation, Parasitology, Aquatic biology