Source Odor, Intensity, and Exposure Pattern Affect Antipredatory Responses in the Subterranean Rodent Ctenomys talarum

BRACHETTA VALENTINA; SCHLEICH CRISTIAN; ZENUTO ROXANA

ETHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 122 p. 923 - 936

0179-1613

Predation is a strong selective force, and prey species may show specificadaptations that allow recognition, avoidance, and defense against predators.Facing a situation of predatory risk, anxiety constitutes a reaction ofadaptive value, allowing to evaluate the potential risk of this encounter aswell as to generate a physiological and behavioral response. Previous studiesin the subterranean rodent Ctenomys talarum revealed that exposure topredator odors (urine or fur) generates an anxiety state and inducesbehavioral changes. However, no differences between the responsesgenerated by both odor sources were observed, although fur odors mayindicate a higher level of predatory immanence. Therefore, the aim ofthis study was to evaluate the behavioral and physiological responses ofC. talarum to different intensities of predator odors (urine and fur) and tothe repeated exposition to the same odorous stimulus. When comparingthe highest behavioral effects elicited by both predatory odors onC. talarum, our study supports the assumption that fur odors are moreanxiogenic than urine, while the former provoked significant changes inthe distance traveled, the number of arm entries and time in transparentarms in the elevated plus maze; cat urine only caused slight changes onthose behavioral parameters. Furthermore, we also found that the intensityof natural predator odor presented to tuco-tucos has a role on theappearance of defensive behaviors, although an amount-dependent relationshipbetween predator odor and anxiety levels was not observed.Finally, while individuals exposed for 1 day to fur odor displayed an evidentanxiety state, those exposed repeatedly for 5 consecutive days didnot differ with the control group in their behavioral response, indicating aclear habituation to the predatory cue. In our intensity and habituationexperiments, we did not find differences in the measured physiologicalparameters among control individuals, exposed to different cues intensity(urine and fur odor) and exposed only once or for 5 days to fur odor.These results provide valuable evidence that the types of predatory odor,along with the frequency of exposition, are important determinants of theappearance, strength, and extinction of defensive behaviors in the subterraneanrodent C. talarum.