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Predation is a key factor in prey population dynamics and could impact population recovery. One common means employed to recover prey populations is that of translocations, but most fail owing to high predation during the early stages. We tested whether conditioned odor aversion can reduce predation during animal translocations by using the predation of the European rabbit Oryctolagus cuniculus by the red fox Vulpes vulpes as a case study. Following a before-after control-impact design (BACI), we deployed bait stations monitored using camera-traps in two zones to which rabbits were translocated. One week before the rabbits were released, microencapsulated levamisole was added to rabbit baits located in the treatment zones, along with vanilla essence as an odor cue. A total of 148 rabbits were distributed in artificial warrens with the odor cue and 68 of them were fitted with radio collars in order to determine their survival rates. The response to the treatment and translocation as regards subsequent rabbit abundance was evaluated using N-mixture models, while rabbit establishment was evaluated using a warren use index (WUI). The treatment decreased the proportion of baits consumed by foxes, but this decrease was partially compensated by other predators. WUI and rabbit population growth increased significantly more after translocations in the treatment zones than in the control zones. The short-term survival of translocated rabbits was also higher in the treatment zones than in the control zones. Our study showed that conditioned odor aversion reduced rabbit predation by foxes, and had a positive effect on rabbit population growth after translocation, since there was an increase in rabbit survival and warren establishment. This method could be used as a non-lethal tool for the recovery of a key prey when carrying out programs concerning the reintroduction of endangered predators or for other vulnerable species requiring translocations., La depredación es un factor clave en la dinámica de la población de presas y podría afectar a la recuperación de la población. recuperación de la población. Un medio habitual empleado para recuperar las poblaciones de presas es el de translocaciones, pero la mayoría fracasan debido a la elevada depredación durante las primeras etapas. En probamos si la aversión condicionada al olor puede reducir la depredación durante translocaciones de animales utilizando la depredación del conejo europeo Oryctolagus cuniculus por el zorro rojo Vulpes vulpes como caso de estudio. Siguiendo un diseño de control-impacto antes-después (BACI), desplegamos estaciones de cebo monitorizadas mediante cámaras-trampa en dos zonas a las que se trasladaron los conejos. Una semana antes de que los conejos fueran Una semana antes de la liberación de los conejos, se añadió levamisol microencapsulado a los cebos situados en las zonas de tratamiento, junto con esencia de vainilla. zonas de tratamiento, junto con esencia de vainilla como señal de olor. Un total de 148 conejos se distribuyeron en las madrigueras artificiales con la señal de olor y a 68 de ellos se les colocaron con radiocollares para determinar su tasa de supervivencia. La respuesta al tratamiento y la translocación en cuanto a la abundancia posterior de conejos se evaluó de conejos, mientras que el establecimiento de los conejos se evaluó mediante un índice de uso de la madriguera (WUI). índice de uso de la madriguera (WUI). El tratamiento redujo la proporción de cebos consumidos por zorros, pero esta disminución fue parcialmente compensada por otros depredadores. El WUI y el crecimiento de la población de conejos aumentó significativamente más después de las translocaciones en las zonas de tratamiento que en las zonas de control. La supervivencia a corto plazo de los conejos translocados conejos translocados fue también mayor en las zonas de tratamiento que en las de control. Nuestro estudio Nuestro estudio demostró que la aversión condicionada al olor redujo la depredación de los conejos por parte de los zorros, y tuvo efecto positivo en el crecimiento de la población de conejos tras la translocación, ya que se produjo un de la población de conejos tras la translocación, ya que se produjo un aumento de la supervivencia de los conejos y del establecimiento de madrigueras. Este método podría utilizarse como una herramienta no letal para la recuperación de una presa clave cuando se lleven a cabo programas de reintroducción de depredadores en peligro o para otras especies vulnerables que requieran translocaciones.

International audience; Previous work has shown that β-adrenergic and GABAergic systems in the basolateral amygdala (BLA) are involved in the acquisition of conditioned odor aversion (COA) learning. The involvement of α 2adrenoreceptors, however, is poorly documented. In a first experiment, male Long-Evans rats received infusions of 0.1 μg of the selective α 2antagonist dexefaroxan (Dex) in the BLA before being exposed to COA learning. In a second experiment, levels of norepinephrine (NE) were analyzed following Dex retrodialysis into the BLA. While microdialysis data showed a significant enhancement of NE release in the BLA with Dex, behavioral results showed that pre-CS infusion of Dex impaired, rather than facilitated, the acquisition of COA. Our results show that the NE system in the BLA is involved in the acquisition of COA, including a strong α 2-receptor modulation until now unsuspected. Supported by the recent literature, the present data suggest moreover that the processes underlying this learning are probably mediated by the balanced effects of NE excitatory/inhibitory signaling in the BLA, in which interneurons are highly involved.

International audience; The retrieval of odor-related memories shapes animal behavior. The anterior piriform cortex (aPC) is the largest part of the olfactory cortex, and it plays important roles in olfactory processing and memory. However, it is still unclear whether specific cellular mechanisms in the aPC control olfactory memory, depending on the appetitive or aversive nature of the stimuli involved. Cannabinoid-type 1 (CB1) receptors are present in the aPC (aPC-CB1), but their potential impact on olfactory memory was never explored. Here, we used a combination of behavioral, genetic, anatomical, and electrophysiological approaches to characterize the functions of aPC-CB1 receptors in the regulation of appetitive and aversive olfactory memory. Pharmacological blockade or genetic deletion of aPC-CB1 receptors specifically impaired the retrieval of conditioned odor preference (COP). Interestingly, expression of conditioned odor aversion (COA) was unaffected by local CB1 receptor blockade, indicating that the role of aPC endocannabinoid signaling is selective for retrieval of appetitive memory. Anatomical investigations revealed that CB1 receptors are highly expressed on aPC GABAergic interneurons, and ex vivo electrophysiological recordings showed that their pharmacological activation reduces miniature inhibitory post-synaptic currents (mIPSCs) onto aPC semilunar (SL), but not pyramidal principal neurons. COP retrieval, but not COA, was associated with a specific CB1-receptor-dependent decrease of mIPSCs in SL cells. Altogether, these data indicate that aPC-CB1 receptor-dependent mechanisms physiologically control the retrieval of olfactory memory, depending on odor valence and engaging modulation of local inhibitory transmission.