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Photo of bee on a flowerToxic nectar and pollen: impacts on flower visitors and role in invasion success?

This project will investigate the ecological impacts of toxic nectar and pollen on flower-visiting insects, and the role toxins may play in invasion by exotic species. Nectar is produced by flowers as food for pollinating animals. However, nectar from some species contains chemicals which may be toxic to flower-visiting insects.
This project will examine the effects of toxic nectar from invasive Rhododendron on native insects and determine why toxic nectar is produced – is it to deter flower visitors that do not pollinate? We will also investigate which Rhododendron species have toxic nectar and how poisonous it is.

Rhododendron ponticum, an invasive species in Ireland, produces toxic nectar and pollen which appears to have little impact on the survival of bumblebees, the main pollinators in Ireland (link to In fact, R. ponticum may act as an important floral resource for these bees. However, other bees (e.g. honeybees) avoid Rhododendron flowers, presumably because they cannot tolerate the toxins.Work is funded by a 4-year SFI RFP grant based on an interdisciplinary collaboration, with Dr Geraldine Wright (link to, Dr Phil Stevenson (link to and TCD Research Associate Dr Mark Brown ( This grant will fund PhD student, Paul Egan (link to Paul’s page) who is based in the Botany Department. In addition, Erin Jo Tiedeken (link to Erin Jo’s page), an international student from the USA, has received an IRCSET PhD scholarship to work on the project.

We will assess the impacts of floral toxins on plant mutualists (pollinators) and antagonists (nectar thieves – insects which visit flowers in order to collect nectar, but who do not transfer pollen and act as pollinators) and explore the extent to which toxic nectar plays a role in invasion by non-native species. Jane in the field











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Last updated 4 April 2013