Professor Dr Bill S. Hansson

Research Priorities: Olfactory system, neuroethological chain of events, reciprocity between insects and host plants
Bill S. Hansson is a Swedish neuroethologist. He works in the field of evolutionary neuroethology, which investigates how neurobiological processes influence behaviours. He researches the evolution of olfactory functions using complete neuroethological chains of events, starting with molecules, genes and neurones, and up to reactions in the entire organism.
Bill S. Hansson and his team look at how habitat and available food resources influence the olfactory systems of arthropods. For this purpose they investigate different related species of fruit flies, with the understanding of how scents enter the brains of insects and how their smells influence their behaviour being key to such investigations. In this way he was able to prove that the olfactory system is crucial for many insects when it comes to survival and reproduction. He analysed, for example, how fruit flies and moths use scent-controlled behaviour to find food, mates, and places to lay eggs, as well as how they use scent signals to avoid enemies, pathogens and toxic environments.
Using the example of the connection between the tobacco hawk moth Manduca Sexta and the tobacco plant, Bill S. Hansson investigates in detail how the communication between insect and host plant works and how the host plant influences the moth’s olfactory function and behaviour. Thanks to its keen sense of smell the moth can find the flower even in complete darkness. When the flower is subjected to high ozone concentrations, however, the moth is not able to find its goal. This is because greenhouse gases such as ozone, nitrogen and carbon dioxide impair the pheromones transmitted between insects. Many pheromones have double bonds that are sensitive to ozone, for example, and can easily break apart. This negatively affects the insects’ communication abilities. Male fruit flies subjected to ozone even lose, for example, the ability to differentiate between male and female flies. This leads to the male flies often trying to court one another.
Bill S. Hansson is also interested in the transition from life in water to life on land for certain crab and insect species. He wants to discover how this transition influenced their olfactory structures and scent-driven behaviours.