Impact of forest fragment size on between-group encounters in lion-tailed macaques

Primate Infectious Disease Ecology: Insights and Future Directions at the Human-Macaque Interface

Global population expansion has increased interactions and conflicts between humans and nonhuman primates over shared ecological space and resources. Such ecological overlap, along with our shared evolutionary histories, makes human-nonhuman primate interfaces hot spots for the acquisition and transmission of parasites. In this chapter, we bring to light the importance of human-macaque interfaces in particular as hot spots for infectious disease ecological and epidemiological assessments. We first outline the significance and broader objectives behind research related to the subfield of primate infectious disease ecology and epidemiology. We then reveal how members of the genus Macaca, being among the most socioecologically flexible and invasive of all primate taxa, live under varying degrees of overlap with humans in anthropogenic landscapes. Thus, human-macaque interfaces may favor the bidirectional exchange of parasites. We then review studies that have isolated various types of parasites at human-macaque interfaces, using information from the Global Mammal Parasite Database (GMPD: http://www.mammalparasites.org/). Finally, we elaborate on avenues through which the implementation of both novel conceptual frameworks (e.g., Coupled Systems, One Health) and quantitative network-based approaches (e.g., social and bipartite networks, agent-based modeling) may potentially address some of the critical gaps in our current knowledge of infectious disease ecology at human-primate interfaces.

Prevalence of gastrointestinal parasites in lion-tailed macaque Macaca silenus in central Western Ghats, India

This study examines gastrointestinal parasites in the endangered lion-tailed macaque, which is sympatric with the bonnet macaque that has relocated from nearby towns or agriculture landscapes dominated by humans and livestock. One hundred and ninety-four fresh fecal samples from lion-tailed macaques were collected from a group located at Chiksuli in the central Western Ghats. Of these, 48.5% had at least one endoparasite taxon. The prevalence of endoparasites varied from 0 to 75.0%, and observed endoparasite taxa varied between 0 and 10 across different months. The prevalence of endoparasites decreased with increasing rainfall and with increasing average maximum temperature across months. Of the 17 endoparasite taxa, 11 were nematodes, two were cestodes, and four were protozoans. The prevalence of Ascaris sp. and Entamoeba coli was higher than the other taxa. The overall load, helminth load, and protozoan load did not differ between months. The overall endoparasite load was greater in immature macaques in all seasons. Helminth load was higher in adult males, especially in the summer. Comparing our findings with those from sympatric relocated bonnet macaques of Chiksuli (Kumar et al. in PLoS ONE 13(11):e0207495, 2018) and lion-tailed macaques of Anamalai Hills (Hussain et al. in PLoS ONE 8(5):e63685, 2013) revealed: (a) a much higher prevalence of endoparasites in lion-tailed macaques from fragments of Anamalai Hills than in lion-tailed and bonnet macaques of Chiksuli; (b) higher richness of endoparasites in both macaque species of Chiksuli than in Anamalai lion-tailed macaques; and (c) more similar composition of endoparasite taxa between the Chiksuli lion-tailed and bonnet macaques than with the Anamalai Hills lion-tailed macaques. We suggest a complete cessation of relocation of commensal animals to the wild habitat. If relocation is necessary, then individuals to be relocated should be thoroughly screened and treated to prevent transferring endoparasite infections to wild populations.

Flocking propensity by satellites, but not core members of mixed-species flocks, increases when individuals experience energetic deficits in a poor-quality foraging habitat

Mixed-species bird flocks are complex social systems comprising core and satellite members. Flocking species are sensitive to habitat disturbance, but we are only beginning to understand how species-specific responses to habitat disturbance affect interspecific associations in these flocks. Here we demonstrate the effects of human-induced habitat disturbance on flocking species' behavior, demography, and individual condition within a remnant network of temperate deciduous forest patches in Indiana, USA. Specifically, we characterized the following properties of two core species, Carolina chickadees (Poecile carolinensis) and tufted titmice (Baeolophus bicolor), across a secondary-forest disturbance gradient: foraging time budgets, home range size, fat scores, fledgling counts, survival rates, and abundance. We also report fat scores for two satellite species that flock with the core study species: white-breasted nuthatches (Sitta carolinensis) and downy woodpeckers (Dryobates pubescens). Finally, we assess mixed-species flock sizes and composition, in addition to avian predator call rates, across the disturbance gradient. Foraging time budgets and home range size were highest and fat scores were lowest for core species in the most-disturbed site. Fat scores of two satellite species followed the same pattern. Additionally, the number of tufted titmice fledglings and winter survival rate of Carolina chickadees were lowest at the most-disturbed site. These results suggest that core species in the most-disturbed site experienced energetic deficits. Moreover, cumulative calling rate of raptors was lowest at the most-disturbed site, and none of the individual raptor species call rates were higher at the most-disturbed site-suggesting that perception of predation risk does not contribute to these patterns. Surprisingly, the satellites continued associating with mixed species flocks through the breeding season at the most-disturbed site. Total flock size and interspecific association patterns were otherwise consistent across the gradient. The fact that satellites continued to flock with core species during the breeding season suggests foraging niche expansion resulting from mixed-species flocking is important in disturbed sites even beyond the winter season. Our study reveals mechanisms underlying flock composition of birds surviving in remnant forest and links the mechanisms to degradation of foraging habitat. These findings offer important insight into the relative impact potential of forest disturbance on mixed-species flocks in the North Temperate Zone.