DOI: 10.5061/dryad.9ghx3ffks
title: Allometry of behavior and niche differentiation among congeneric African antelopes

description: Size-structured differences in resource use stabilize species'
 coexistence in animal communities, but what behavioral mechanisms underpin
 these niche differences? Behavior is constrained by morphological and
 physiological traits that scale allometrically with body size, yet the
 degree to which behaviors exhibit allometric scaling remains unclear;
 empirical datasets often encompass broad variation in environmental
 context and phylogenetic history, which complicates the detection and
 interpretation of scaling relationships between size and behavior. We
 studied the movement and foraging behaviors of three sympatric, congeneric
 spiral-horned antelope species (Tragelaphus spp.) that differ in body
 mass—bushbuck (Tragelaphus sylvaticus, 26–40 kg), nyala (Tragelaphus
 angasii, 57–83 kg), and greater kudu (Tragelaphus
 strepsiceros, 80–142 kg)—in an African savanna ecosystem where
 (i) food was patchily distributed due to ecosystem engineering by
 fungus-farming termites and (ii) predation risk was low due to the
 extirpation of several large carnivores. Because foraging behavior is
 directly linked to traits that scale allometrically with size (e.g.,
 metabolic rate, locomotion), we hypothesized that habitat use and diet
 selection would likewise exhibit nonlinear scaling relationships. All
 three antelope species selected habitats near termitaria, hotspots of
 abundant, high-quality forage. Experimental removal of forage from termite
 mounds sharply reduced the use of those mounds by bushbuck, confirming
 that habitat selection was resource-driven. Strength of selection for
 termite mounds scaled negatively and nonlinearly with body mass, as did
 recursion (frequency with which individuals revisited locations), whereas
 home-range area and mean step length scaled positively and nonlinearly
 with body mass. All species disproportionately ate mound-associated plant
 taxa; nonetheless, forage selectivity and dietary composition, richness,
 and quality all differed among species, reflecting the partitioning of
 shared food resources. Dietary protein exhibited the theoretically
 predicted negative allometric relationship with body mass, whereas
 digestible-energy content scaled positively. Our results demonstrate
 cryptic size-based separation along spatial and dietary niche axes—despite
 superficial similarities among species—consistent with the idea that
 body-size differentiation is driven by selection for divergent
 resource-acquisition strategies, which in turn underpin coexistence.
 Foraging and space-use behaviors were nonlinearly related to body mass,
 supporting the hypothesis that behavior scales allometrically with size.
 However, explaining the variable functional forms of these relationships
 is a challenge for future research.
description: This dataset comprises multiple data types collected in Gorongosa
 National Park, Mozambique, from 2014-2016. These include metadata for each
 GPS-collared antelope and fecal sample; summary data on diet composition,
 diet quality, and food-plant availability; survey data on overstory plant
 canopy cover, basal area, and species identity; data on foliar nutrient
 content of plants growing on and off termite mounds; GPS data for each
 antelope and random locations used to assess habitat selection at
 landscape and home-range scales; termite mound coordinates digitized from
 LiDAR imagery; shapefiles with vegetation and lion-utilization layers;
 data from the forage-removal experiment; derived data on antelope home
 ranges, step lengths, site revisitation, and mound densities within home
 ranges, as used in analyses; Illumina data and unrarefied sequence count
 tables; and the local reference library used to identify fecal DNA
 sequences in DNA metabarcoding analyses.
description: Please see ReadMe file for additional information on data
 interpretation and usage.