Daily activity patterns in agoutis (Dasyprocta spp) in response to relaxed predation.

Abstract

Animals' fitness is determined in a large proportion by the balance in energetic requirements maintained during daily activities, in response to environmental factors. Predation is a major environmental factor influencing the activity patterns of prey, and the deployment of adaptive responses to predation represents a significant cost to prey populations and communities. Experimental removal of predators to study the effect on activity patterns of prey is impractical for vertebrate species. However, islands are often deprived of predators and provide an excellent arena to study prey's responses in the absence of any cue related to predation risk. Here, we investigated whether natural absence of predators in islands has influenced the activity patterns of diurnal agoutis in Panama, by monitoring activity in three sites in each habitat type (predator-free vs predator). We predicted that agoutis in predator-free sites can expand their activity patterns towards the night, which is the period of highest predation risk, in sites with predators. One of our predator-free sites showed relative high activity at night, with no evidence of nocturnality in sites with predators. A clear pattern across our three predator-free sites was that agoutis started their daily activity earlier, before sunrise, which is a period with significant predation risk as well. Our study highlights the role that felids play in regulating agoutis' daily activity patterns and we discuss the implications of our finding. Finally, we also offer a review on agoutis' activity pattern in the Neotropics.