TEMPORAL CHANGES IN OLFACTORY PREFERENCE IN MURID RODENTS REVEALED BYLIVE-TRAPPING

We investigated the responses of the wood mouse (Apodemus sylvaticus) and bank vole (Clethrionomys glareolus) to odor in traps by examining the capture rate of live-traps with respect to their immediate trappin g, and therefore semiochemical, history. Both bank voles and wood mice preferred traps previously occupied by conspecifics. However, bank vo les showed no sexual bias to this preference, whereas wood mice exhibi ted a significant preference for traps that had been occupied by membe rs of the opposite sex. In accordance with current theories on their b reeding system, wood mice showed sexual differences, both in their rea ction to the odor of members of the same sex and in the temporal natur e of their reaction to conspecific odor. Wood mice also avoided traps that had previously held bank voles. The results indicate that live-tr apping data may reveal important semiochemical interactions between bo th heterospecific and conspecific animals and highlight the need for c aution, both in the deployment of traps and the analysis of data, when using such techniques for the enumeration of populations.