AbstractsBiology & Animal Science

Lyme disease is an infectious zoonotic disease caused by the spirochete bacterium Borrelia burgdorferi sensu lato. In North America, it has a number of vertebrate hosts including the white-footed mouse (Peromyscus leucopus). The disease is transmitted to other vertebrates, including humans, through the bite of an infected black–legged tick (Ixodes scapularis). In recent years there has been an increase in the incidence of Borrelia burgdorferi in southern Quebec, coinciding with the range expansion of the white-footed mouse and the black-legged tick in the region. This increasing distribution of reservoir and vector will undoubtedly favour the emergence and spread of Lyme disease in the parts of the province where they both become more abundant. As a generalist species, the white-footed mouse is favoured in fragmented landscapes like the Monteregie area, where it has been displacing the deer mouse (Peromyscus maniculatus), its local competitor. In this region we evaluated the effects of stress level, parasite load and some forest patch characteristics on white-footed mouse movement patterns. We found a negative effect of the adrenal gland size, a proxy for stress level, on the home range area and the movement rate of mouse individuals, suggesting that stressed mice cannot defend large home ranges. White-footed mouse population densities had a negative effect on the home range area and on the movement rate, consistent with higher competition rates and conflict avoidance behaviours in these sites. Population density also influenced the excursion (outside the forest patch) and exploration (outside the home range) rates, either directly or indirectly through its effect on home range area and movement rate. Finally, we found that the load of ticks had a negative effect on movement rate. P. leucopus densities and stress levels are good predictors of the movement patterns in this species and can be used to better understand its dispersal dynamics at the front of its distribution range. This will contribute to better predict the rate and pattern of Lyme disease expansion and identify high-risk areas for the disease. La maladie de Lyme, une zoonose infectieuse causée par la bactérie spirochète Borrelia burgdorferi sensu lato. En Amerique du Nord, cette maladie implique plusieurs hôtes vertébrés, dont la souris à pattes blanches (Peromyscus leucopus). La maladie est transmise à d'autres vertébrés, dont l'humain, par la morsure d'une tique à pattes noires (Ixodes scapularis) infectée. Ces dernières années ont vu l'incidence de Borrelia burgdorferi augmenter dans le sud du Québec, coïncidant ainsi avec l'extension des aires de distributions de la tique et de la souris dans la région. L'augmentation de la distribution du réservoir ainsi que du vecteur va indubitablement favoriser l'émergence et la propagation de la maladie dans les zones de la province où ces deux acteurs deviennent plus abondants. En tant qu'espèce généraliste, la souris à pattes blanches est favorisée dans les paysages fragmentés comme en Montérégie, où elle…