Plasticity in the timing of activity in the Red-rumped Agouti, Dasyprocta leporina (Mammalia: Rodentia), in the Atlantic Forest of southeastern Brazil

Laura Martins Magalhães,Ana Carolina Srbek-Araujo

doi:10.1590/1676-0611-bn-2018-0625

Abstract

Abstract Timing of activity is a consequence of adaptations to daily and seasonal changes in the environment and examining these patterns is important to better understand the temporal niches of the species. Here we examine temporal activity in the Red-rumped Agouti (Dasyprocta leporina) in two fragments of Atlantic Forest and those factors that influence the circadian rhythm in the study areas. Camera traps were used to gather data in two protected areas (one montane and other coastal) in the state of Espírito Santo, southeastern Brazil. A total of 49 photos were taken in the mountains and 152 in the coastal area. Activity patterns were diurnal and bimodal, and animals were active for 14-15 hours each day. Activity peaked in the morning soon after sunrise and then before and during dusk. Activity patterns were different in the two study areas (W = 6.77, p = 0.034). There was a longer peak in the morning in the coastal area, and a higher peak in the evening in the mountains, where activity starts later and becomes less intense earlier. The difference between activity patterns in the two locations suggests plasticity in agouti behavior. Because the two study areas are at about the same latitude, we suggest that the behavioral plasticity is due to different temperature regimes associated with a local effect of altitude and topography of the terrain on the incidence of solar rays inside the forest. The influence of other factors is also discussed. In addition to a better understanding of the temporal niche of the Red-rumped Agouti, the behavior patterns we describe here can be useful to optimize strategies for D. leporina conservation in southeastern Brazil once the species is more susceptible to poaching at times when animals are most active.

Highlights

Circadian rhythms are intervals of approximately 24 hours during which the vital biological processes that maintain organisms occur (Goldman 1999) and are part of the suite of adaptations of species to their environments
Agoutis had a total of about 14 hours of activity in the EBSL, most of which occurred during two peaks
The two intervals with the most activity, after sunrise and before and during dusk, are similar to the daily activity patterns of agoutis in different parts of the Americas (Oliveira & Bonvicino 2006, Lambert et al 2009, Norris et al 2010, Suselbeek et al 2014, Cid et al 2015, Ferreguetti et al 2018). This pattern differs from that observed in Ecuador (Blake et al 2012) and Panama (Duquette et al 2017), where the activity pattern was unimodal

Summary

Introduction

Circadian rhythms are intervals of approximately 24 hours during which the vital biological processes that maintain organisms occur (Goldman 1999) and are part of the suite of adaptations of species to their environments. Patterns of sleep-vigilance, variable body temperature, hormone and enzyme secretions and regulation of cell cycles (among others) are consequences of circadian rhythms (Kronfeld-Schor & Dayan 2003, Pita et al 2011) These patterns are due to as biological clocks that provide the organisms with the mechanisms to anticipate and prepare for daily changes that occur regularly in the environment (Goldman 1999). This is due to the fact that patterns of activity are molded by selective forces (e.g., ecological interactions) and evolutionary constraints (e.g., functional and morphological constraints, genetic variability), that are the basis of time partitioning among species and that, in turn, may allow or not species coexistence (Kronfeld-Schor & Dayan 2003)

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Conclusion