The Influence of Leaf Consumption on Time Allocation in Black Howler Monkeys (Alouatta pigra)

Abstract

The analysis of factors that determine variation in time budgets is important to understand the interactions between environment, behaviour and fitness. We tested the hypothesis that changes in the dietary patterns of black howler monkeys (Alouatta pigra) caused by a decrease in the availability of preferred foods are a main determinant of variation in time budgets. We predicted that individuals would trade off travel time for resting time (i.e., minimize energy expenditure) as the diet included more leaves. We conducted our study in the Mexican state of Campeche between 2005 and 2008, where we studied the behaviour of 28 adult males and 32 adult females belonging to 14 different groups for a total of 3,747.2 focal sampling hours. Study groups lived in forest fragments with variation in habitat quality. Individuals showed different rest:travel trade-offs in response to leaf consumption according to the quality of the forest fragments they lived in. Individuals that lived in high-quality fragments increased resting time under more folivorous regimes, whereas those living in low-quality fragments increased travel time. Our results suggest that howler monkeys living in low-quality fragments spend more time foraging to compensate for the low quality of the available resources.

Behavioral and physiological stress responses to local spatial disturbance and human activities by howler monkeys at Los Tuxtlas, Mexico

“…Therefore, even if behavioral flexibility allows coping with time‐budget adjustments without incurring fitness costs (Abrams & Schmitz, ), the long‐term impact of such human‐induced variation is less clear. It has been predicted, for instance, that under certain climate change scenarios, variation in time‐budgets may be insufficient to allow for survival (Lehmann, Korstjens & Dunbar, ), and that energy‐demanding time‐budgets may reduce the fecundity of howler monkeys living in small forest fragments (Rangel‐Negrín et al , ). Second, although the fitness consequences of glucocorticoid modulation in wildlife in response to anthropogenic disturbance are still unclear (Bonier et al , ; Boonstra, ; Beehner & Bergman, ), there is evidence that stress physiology may be critical for individual survival when facing unpredictable challenges (Romero & Wikelski, ).…”

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

“…On the other hand, similar to the exploitation of cultivated species (Chaves & Bicca‐Marques, ), food supplementation can also mitigate the seasonal variation in the availability of wild foods, characteristic of low‐quality habitat patches (Rangel‐Negrín, Coyohua‐Fuentes, Canales‐Espinosa, & Dias, ), thereby facilitating survival and increasing the reproductive success of supplemented animals (Kurita, Sugiyama, Ohsawa, Hamada, & Watanabe, ; Maréchal et al, ; Strum, ). The births of three infants soon after the end of the study in the winter (two in JA in August and one in RO in September; J. P. Back, pers.…”

Effects of variation in forest fragment habitat on black howler monkey demography in the unprotected landscape around Palenque National Park, Mexico

“…In a fragmented landscape, both resources (Heinrichs et al, 2015;Rangel-Negrín et al, 2018) and mating opportunities (Gros, Poethke & Hovestadt, 2009) may be subject to substantial spatiotemporal variation. Owing to differences in reproductive costs and investments (Trivers, 1972), ecological theory predicts that female mammals will often compete more over food resources, while males compete more over reproductive opportunities (Gros, Poethke & Hovestadt, 2009).…”

“…Black howlers are generally considered adaptable to habitat fragmentation. Groups are found in very small forest fragments (<2 ha; Rangel-Negrín et al, 2018 ; Klass, Van Belle & Estrada, 2020 ), and black howlers display considerable flexibility in their folivorous/frugivorous diet, which may allow them to persist in degraded habitat ( Dias et al, 2014 ; Bicca-Marques, Chaves & Pacheco Hass, 2020 ). However, they prefer tall trees (>15 m in height; Gonzalez-Kirchner, 1998 ), which may be rarer in small or secondary growth fragments.…”

“…However, they prefer tall trees (>15 m in height; Gonzalez-Kirchner, 1998 ), which may be rarer in small or secondary growth fragments. Moreover, studies have shown that residing in poorer quality habitat or smaller fragments can have negative impacts on their health and fitness ( Rangel-Negrín et al, 2018 ), and that some black howler demographic parameters (population growth, infant survival) are adversely affected by decreasing fragment sizes and increased habitat disturbance ( Rangel-Negrín et al, 2018 ).…”