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Sheep tick (Ixodes ricinus). © INRA, CHAUBET Bernard

Tick-fighting tactics

Small mammals, ticks, and agricultural landscapes

How landscape features affect tick abundance.

Updated on 10/14/2016
Published on 04/01/2016

The transmission of tick-vectored diseases is shaped by ecological interactions among ticks, their pathogens, and their vertebrate hosts. Indeed, the relative abundances of these groups and the nature of their relationships depend on landscape features.

The ANR-funded OSCAR project, led by the Joint Research Unit BIOEPAR, has been studying the relationships among small mammal species and the tick Ixodes ricinus, which vectors a variety of zoonoses, within a wooded agricultural landscape. More specifically, researchers examined the mammals’ ability to serve as hosts for tick larvae. Two rodent species were common along grassland edges, namely the wood mouse and the bank vole.

The study showed that landscape structure, such as the amount of wooded area and hedgerow length, affected rodent abundance. For instance, dense networks of hedgerows and thickets increased wood mouse numbers, while more isolated habitats were better for bank voles. Overall, the wood mouse seems to be a better host for tick larvae and thus has a positive effect on tick abundance in the environment. In contrast, the host capacity of bank voles varies seasonally. One explanation could be that bank voles acquire immunity to ticks by the time they become adults and that only young voles, present in the autumn, can serve as good hosts for tick larvae. Regardless of host capacity, tick abundance was only weakly correlated with rodent abundance, likely because other factors are operating (e.g., climatic conditions and vegetation features). This work is part of a more general effort to examine the effect of biodiversity on the circulation of zoonotic diseases transmitted from wild reservoirs to humans and domestic animals.

These findings demonstrate that landscape features can influence tick abundance because they affect the abundance of different small mammal species. Because these mammals vary in their abilities to host pathogens, pathogen transmission is also affected by landscape characteristics. Further research is currently examining pathogen dynamics.

Collaborators: Alain Butet (research scientist, ECOBIO Joint Research Unit [CNRS and University of Rennes]) and Suzanne Bastian (assistant professor, BIOEPAR Joint Research Unit [INRA and Nantes-Atlantic National College of Veterinary Medicine, Food Science, and Engineering]) served as co-advisors to Grégoire Perez. Perez received a doctoral fellowship from the regional government of Brittany.

Reference: Perez, G., Bastian, S., Agoulon, A., Bouju, A., Durand, A., Faille, F., Lebert, I., Rantier, Y., Plantard, O., & Butet, A. (2016). Effect of landscape features on the relationship between Ixodes ricinus ticks and their small mammal hosts. Parasites & Vectors, 9.  DOI: 10.1186/s13071-016-1296-9

Scientific contact(s):

Associated Division(s):
Animal Health
Associated Centre(s):
Pays de la Loire

Find out more

ANR-funded OSCAR research project

Tick-related disease risks as a function of wooded-agroecosystem landscape features

This project is led by the Joint Research Unit BIOEPAR and brings together five research groups to study the ecology of hosts, vectors, and pathogens.
www6.inra.fr/oscar (link in French)