Influence of diverse olfactory cues on social, foraging, and spatial behaviours of the bank vole

Olfaction mediates many aspects of the bank vole’s life. However, all the mechanisms are far from being fully understood. In the present context of habitat fragmentation, to study how olfactory cues can mediate its social processes, influence its active search for biotic resources and elicit its movements appears to be of major interest and is the main objective of this PhD-thesis. The research started with three behavioural experiments, performed under laboratory conditions. Bank voles were found to behave differently to scent marks according to the population of origin of the marker. They react more to odours from OPO conspecifics (i.e. members of an Other Population of Origin) than to odours from conspecifics belonging to their own population. A field enclosure experiment was then set up in order to study the ability of bank voles to distinguish between different artificial odours (i.e. extracted with methanol) sprayed on food. The results confirmed the attractiveness of OPO conspecific odours even extracted with methanol and tested in outdoor conditions. On the other hand, odours from terrestrial predators (i.e. weasel and red fox) were found to be strongly repulsive. The most attractive artificial olfactory marker (i.e. from OPO conspecific) and the most repulsive one (i.e. from weasel) were then tested on the spatial behaviour of voles. Both were used in a complex maze with attractive markers placed in pathways leading to the goal and repulsive markers placed in pathways to be avoided. Results obtained were inconclusive, none of the artificial marker showed an influence on movements of bank voles. As voles did not take heed of artificial markers while moving, we hypothesised that natural scented trails created by conspecifics, should direct the bank voles to the goal more efficiently than artificial markers did. However, the overall movements of bank voles were not significantly influenced by the presence of natural odours of conspecifics either. Original and convincing results were found on the use of olfaction in social and foraging contexts in bank voles. However, this four-year research did not come up with findings on whether and how olfactory cues can influence their spatial behaviour. The idea is worthwhile pursuing as proposed in the perspectives, and there is hope that in the future we may understand which elements elicit movements of bank voles for helping to counteract the impacts of habitat fragmentation on populations.(BIOL 3) -- UCL, 200