Resumen de Switching between Food Patches Suggests a Need to Balance Nutrients while Foraging in Wild Black Howler Monkeys (Alouatta pigra)
Nicoletta Righini, Paul A. Garber, Jessica M. Rothman, Minerva S. Santillán Rivera, Antonio López Espinoza
Studies of feeding patch choice in primates have traditionally analyzed individual foraging decisions in relation to patterns of social foraging,dominance, and feeding competition. However, information on detailed ecological and nutritional characteristics of the patches also is neededto understand the basis of feeding patch preferences. In particular, recent models of nutritional ecology have stressed the importance of nutrientbalancing as a primary driver of individual foraging decisions. Here we investigated the behavioral and nutritional factors affecting feeding patchchoice in black howler monkeys (Alouatta pigra) during a 15-month field study in Campeche, Mexico. We collected 1300 hours of behavioral dataon 14 focal animals, including full-day follows of one individual/day recording all feeding activities. We carried out nutritional analyses of foodsfrom feeding trees and calculated daily nutrient intake. A total of 690 trees (i.e., patches) were visited throughout the study period. The time spentfeeding and the amount of food consumed differed significantly according to patch type. Individuals consumed more food in mature and immaturefruit patches than in mature leaf, young leaf, and flower patches. Protein intake rates (kJoule/min) were similar in young and mature leaf patches,and higher than in mature fruit, immature fruit, and flower patches, among which the rate was similar. In the majority of the cases (80.3%), thefocal animals left the feeding patch prior to satiation. On those occasions, resource mixing, or moving from one food type to another food type,accounted for 49.4% of the patch leaving events. The fact that black howler monkeys alternated feeding bouts between fruit and leaf patches, aswell as alternating bouts of higher and lower protein intake, suggest that this pattern could be dictated by the need to balance nutrients.
