Of mice and cats: interspecific variation in prey responses to direct and indirect predator cues

Abstract: Prey behavioral responses to predation risk cues may vary between species; moreover, the strength of these behaviors may differ depending on risk cue. In northwestern Taiwan, we used the giving up density (GUD) framework supported with camera trap observations to test how two wild murid rodents that differ by up to fivefold in body size (striped field mouse, Apodemus agrarius, and lesser rice-field rat, Rattus losea) altered their foraging behavior depending on microhabitat characteristics (indirect predator cues) and exposure to predator odors (direct predator cues) of three felids: the native leopard cat (Prionailurus bengalensis), the introduced domestic cat (Felis catus), and the exotic bobcat (Lynx rufus). GUD was not affected by predator odors but rather by microhabitat type; rodents removed more seeds under the cover of vegetation compared to exposed food stations, which may reflect a proactive approach to avoiding high-risk areas in a heterogeneous environment. The smaller mouse, A. agrarius, spent more time foraging in experimental food patches compared to the larger rat, R. losea, irrespective of predator odor. Conversely, R. losea spent more time investigating stations and exhibiting vigilance compared to A. agrarius. Species-level differences are consistent with behavioral phenomenon that smaller, “faster” species confer more boldness compared to larger, “slower” species, which reinforces the connection between behavior and pace of life, and further elucidates how the behavior of different prey species may not be interchangeable in contexts of risk. Significance statement: In the wild, animals eat while trying not to be eaten. Therefore, preys often change their behavior in response to risk cues, but the intricacies of these behavioral shifts can be complex and vary between species. With the use of camera trap monitoring and experimental food patches, we were able to examine fine-scale species-specific behaviors and test for dissimilarities. Two species of wild rodents did not change their foraging behavior to the addition of predator odors, but we did observe an interspecific behavioral variation. The smaller, “faster” rodent species spent more time foraging, while the larger, “slower” species spent more time vigilant with more thorough investigation. These interspecific behavioral differences likely indicate the smaller species demonstrated more boldness, whereas the larger rodent was more cautious, which is consistent with the association between pace of life (POL) and behavior.