GELIFES Seminars - Emily Burdfield-Steel

Emily Burdfield-Steel (University of Amsterdam)

Chemicals and colours

Uncovering the chemical signals maintaining aposematic warning signal variation

Aposematic warning signals are expected to be under stabilising selection, leading to monomorphic signalling within and even across populations. However, there are many exceptions to this rule, perhaps one of the most heavily studied being the Wood Tiger Moth, which shows distinct colour polymorphism in males. Investigation into the possible mechanisms maintaining this polymorphism revealed that positive frequency dependent selection is indeed acting on these colour morphs, on both small and large scales. Our attempts to better understand both their chemical defences, and how these interact with their warning signals, revealed that these moths primarily use pyrazines to repel avian predators. We also found differences in chemical defences between the colour morphs, although these also did not explain how both morphs were able to co-exist. It wasn’t until we looked at the pheromone signals used by the females to attract mates that we discovered a possible answer to the question: why aren’t all wood tiger moths white? This result highlights the importance of considering all modes of communication when seeking to understand the selective forces acting upon a species. Finally, I will discuss some more recent work looking to understand how human activities can disrupt these different communication modes, and the potential effects on aposematic signalling.

Biosketch:
Emily did her PhD at the University of St Andrews on sexual selection and reproductive interference, before moving first to the University of Jyvaskyla in Finland, and then Macquarie University in Australia, to work on aposematism - aka the use of bright colours to signal chemical defences. She joined the University of Amsterdam in 2019 as an Assistant Professor, where her work focuses on chemical and visual communication in insects. She is interested in how intra- and inter-specific species communication shapes evolutionary processes.

Link to seminar