Samantha McCarren will present the Department of Biological Sciences seminar with a talk about her PhD thesis entitled "Floral evolution of long-tubed Erica species"


The Cape Floristic Region, with its over 9,000 species of vascular plants, is an area of extraordinarily high diversity and endemism. About 69% of the plants are endemic and many genera show high rates of speciation. There are two contrasting (but non-exclusive) main hypotheses: The speciation might have been driven by heterogeneity of pollinators or by heterogeneity in the abiotic environment. Erica is a specifically suitable genus for studying speciation because of its extreme radiation with a diversity of flower morphologies, pollination systems and occurrence in a range of different habitats and soil types. I have already studied the role of UV in Erica species for their pollination and I have studied the role of corolla stickiness as a defence against nectar robbing. For my PhD, I aim to study the role of exserted anthers for pollen transfer and species co-occurrence. I also plan to research the benefits of being bird-pollinated by looking at pollen transfer efficiency. Further, I will look at the reproductive barriers between the sister species E. shannonii and E. ampullacea and I will use vegetation surveys to compare the distribution of bird- and insect-pollinated Erica species in relation to abiotic factors.  

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