Seasonal variability in the diet and feeding ecology of black-and-white ruffed lemurs (Varecia variegata) in Ranomafana National Park, southeastern Madagascar.

Abstract

We characterized the diet and foraging ecology of the black-and-white ruffed lemur (Varecia variegata), a specialized frugivore, and investigated behavioral strategies exhibited in response to seasonal changes in resource availability. Behavioral data were collected from the same two adjacent communities across 29 months during two observation periods (2007-2008; 2017-2018) in Mangevo, a primary rainforest habitat in southeastern Madagascar. To analyze feeding in the context of energy maximization versus time minimization strategies, we used nonparametric tests to compare plant part constituents, dietary diversity, activity budgets, and canopy strata use between fruit-abundant versus fruit-lean seasons. Individuals dedicated ~30% of their time to feeding year-round, mostly in the middle canopy (11-20 m). Animals fed primarily on fruits (74% of diet), but frugivory decreased and folivory increased markedly during fruit-lean seasons. Abundant season dietary diversity (98 taxa, H' = 0.71-1.37) was greater than lean season diversity (70 taxa, H' = 0.56-1.06), which coincided with less traveling, more resting, and higher canopy use-though interannual variation was observed. Herein, we describe behavioral and dietary patterns that are concordant with a time minimizing behavioral strategy. Black-and-white ruffed lemur diets comprised lower taxonomic diversity, fewer fruits, and more leaves during fruit-lean months. Further, shifts toward less travel, more resting, and greater use of higher canopy levels during this time were most likely for thermoregulatory benefits.