Supplemented howler monkeys eat less wild fruits, but do not change their activity budgets

Abstract

Research on the influence of food supplementation on primate behavior has focused on terrestrial and semiterrestrial species. Its effects on highly arboreal species are poorly known. We assessed the influence of food supplementation on the feeding behavior and activity budget of four adult female and two adult male brown howler monkeys (Alouatta guariba clamitans) belonging to two groups (JA and RO) that inhabited periurban forest fragments in southern Brazil. We used the "focal-animal" method during 6-8 full days per month from March to August 2017 (916 h of observation) to record the behavior of the study subjects. The feeding events of the focal individual were recorded using the "all occurrences" method. The supplementation was unevenly distributed during the day and accounted for 5-6% of all feeding events of male and female howlers, respectively. JA always received fruit in a platform, whereas RO had access to fruits and processed foods on roofs and directly from humans. The mean biomass of wild foods ingested by each adult per day was >300% higher than the ingested biomass of supplemented foods (females: 395 vs. 109 g/day; males: 377 vs. 120 g/day), but the ingestion rate of supplemented foods was ca. 400% higher than that of wild foods (females: 17 vs. 4 g/min; males: 19 vs. 5 g/ min). The activity budgets of females and males were dominated by resting (66-72%) followed by feeding (18-14%), moving (12-11%), and socializing (2%). We found that food supplementation reduced the ingestion of wild fruits, but it did not affect the howlers' need to ingest a given amount of leaves per day and the time spent resting, feeding, moving, and socializing. K E Y W O R D SAlouatta guariba clamitans, anthropic food, behavioral flexibility, diet, human-wildlife interaction, provisioning

Female reproductive energetics in mantled howler monkeys (Alouatta palliata): A follow‐up study

“…Still, this dietary flexibility is constrained, as under highly folivorous diets individuals lose weight (Espinosa‐Gómez et al, 2013). Additionally, behavioral flexibility of howler monkeys may be constrained by their energy‐saving ecological strategy, as time‐budgets are conserved across a wide range of contexts (Back & Bicca‐Marques, 2019; Bicca‐Marques, 2003; Cristóbal‐Azkarate & Arroyo‐Rodríguez, 2007) and physiological stress increases when individuals are more active (Dias et al, 2017; Dunn et al, 2013). Thus, howler monkeys are an interesting model to explore the interaction between metabolic function and behavioral flexibility.…”

Wildlife is imperiled in peri-urban landscapes: threats to arboreal mammals

“…Species that cope with these peri-urban stressors can exploit food patches containing native and cultivated plants and human-provisioned or wasted foods in the matrix (e.g. Alouatta guariba clamitans: Chaves and Bicca-Marques, 2017;Corrêa et al, 2018;Back and Bicca-Marques, 2019;Cebus imitator: Mckinney, 2011;…”

“…Species that cope with these peri-urban stressors can exploit food patches containing native and cultivated plants and human-provisioned or wasted foods in the matrix (e.g. Alouatta guariba clamitans: Chaves and Bicca-Marques, 2017;Corrêa et al, 2018;Back and Bicca-Marques, 2019;Cebus imitator: Mckinney, 2011; Saguinus bicolor: Gordo et al, 2013). However, peri-urban primates are also exposed to the aforementioned intense vehicle traffic in roads and highways, powerline networks, dog attacks and human mistreatment while navigating between food patches (e.g.…”

“…Papio ursinus : Beamish and O’Riain, 2004; Pan troglodytes : Cibot et al, 2015; Chlorocebus pygerythrus : Chapman et al, 2016; Colobus angolensis and Cercopithecus mitis : Cunneyworth and Slade, 2021) and the Americas (e.g. Alouatta guariba clamitans : Chaves and Bicca-Marques, 2017; Corrêa et al, 2018; Back and Bicca-Marques, 2019; Cebus imitator : Mckinney, 2011; Saguinus bicolor : Gordo et al, 2013). However, peri-urban primates are also exposed to the aforementioned intense vehicle traffic in roads and highways, powerline networks, dog attacks and human mistreatment while navigating between food patches (e.g.…”

“…The brown howler monkey ( Alouatta guariba clamitans ) is a Vulnerable (Buss et al, 2019) endemic Atlantic Forest primate found in isolated forest patches immersed in peri-urban and rural landscapes of south and southeastern Brazil. The taxon’s ecology and behavior are well-known, particularly in south Brazil (Martins, 2006; Buss, 2012; Chaves and Bicca-Marques, 2013, 2017; Chaves et al, 2018; Corrêa et al, 2018; Back and Bicca-Marques, 2019). However, the lack of long-term data on the influence of peri-urban threats on its populations compromises our assessments of their conservation importance.…”