Are larger primates less faunivorous? Consumption of arthropods by Amazonian primates does not fulfil the Jarman-Bell and Kay models

Abstract

Terrestrial arthropod groups, including insects, spiders, and millipedes, represent an important food resource for primates. However, species consumed and patterns and rates of arthropod-related feeding for most frugivorous primates are still poorly known. We examined stomach contents of 178 Amazonian primate specimens of nine genera and three families obtained from community-based collections voluntarily donated by subsistence hunters. Based on our results, we assessed whether consumption patterns followed the expected negative relationship between arthropod ingestion and body size as postulated in the Jarman-Bell and Kay models. We identified 12 consumed arthropod taxa, including insects (beetles, grasshoppers, ants, flies, caterpillars, praying mantises, and others), spiders and millipedes. Medium and large-bodied primates consumed a greater diversity (measured by Simpson’s diversity index) and richness of arthropods, but differed in terms of composition of taxa consumed. Cacajao, Sapajus and Cebus consumed proportionally more Orthoptera and Coleoptera compared to the other primate genera analyzed. We did not find significant correlations between richness and diversity of arthropods consumed and primate body mass. There was a slight tendency for the decrease in the relative content of arthropods in the diet with increased body mass in medium and large primates, which does not provide full support for the Jarman-Bell and Kay models. The study of arthropod consumption by arboreal primates in the wild remains challenging. Our study suggests that arthropods supply essential nutrients for frugivorous primates, and provides an alternative method to analyse faunal consumption patterns in primates.

Comparative gastrointestinal organ lengths among Amazonian primates (Primates: Platyrrhini)

“…This is unexpected, since observational studies in Cacajao indicate that 85% of their diet are immature seeds and unripe fruits (Bowler & Bodmer, 2011; Norconk et al, 2009), which would theoretically require cecal detoxification (Ayres, 1989; Rosenberger, 1992). Nonetheless, studies of stomach contents reported the consumption of high diversity of arthropods for Cacajao , comparable to the diets of Cebus and Sapajus , while Pithecia consumes comparatively a lower diversity of arthropods (Jesus, Castilla Torres, et al, 2022; Torres et al, 2022). Hence, the unexpected differentiation in the digestive morphology of Cacajao and its high similarity with cebines may be explained by the long small intestine related to the digestion of large amounts of animal matter.…”

“…The relatively larger stomach of Alouatta can store larger food volumes, consistent with their highly folivorous diet (~50%, Norconk et al, 2009) and longer food transit time (e.g., ~35 h for A. seniculus , Crissey et al, 1990). Cacajao , by contrast, presents the lowest stomach capacity relative to its body size, suggesting a diet composed mostly of highly digestible items, such as arthropods (e.g., Barnett et al, 2013; Jesus, Castilla Torres, et al, 2022; Torres et al, 2022) and seeds with lower fiber content (Norconk, 2020), and a short transit time (e.g., ~5 h for C. calvus , Milton, 1984).…”

“…The use of biological samples donated by subsistence hunters has provided relevant ecological (e.g., Mayor et al, 2015), reproductive (e.g., Andrade et al, 2018;El Bizri et al, 2018;Mayor et al, 2017), feeding (e.g., Jesus, Castilla Torres, et al, 2022;Torres et al, 2022) and parasitic (e.g., Conga et al, 2019;Gomez-Puerta et al, 2020;Jesus, Oliveira-Ramalho, et al, 2022) data affecting wildlife populations in these areas. These results have been transmitted to the participating communities in meetings and via educational materials.…”

“…Cacajao, by contrast, presents the lowest stomach capacity relative to its body size, suggesting a diet composed mostly of highly digestible items, such as arthropods (e.g., Barnett et al, 2013;Jesus, Castilla Torres, et al, 2022;Torres et al, 2022) and seeds with lower fiber content (Norconk, 2020), and a short transit time (e.g., $5 h for Milton, 1984).…”

Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys—A literature review

“…Woolly monkeys live in heterosexual groups of 12–40 individuals, forming subgroups that maintain auditory contact (Defler, 1989). In the wild, woolly monkeys have a diet based mainly on fruits, but leaves and arthropods also are included, especially in the diets of infants and nonpregnant females (Jesus et al, 2022; Stevenson et al, 1994; Torres et al, 2022). The ingestion of arthropods reduces conflict in the group during periods with lower fruit availability, because juveniles and nonlactating females feed on more insects, while dominant males and lactating females ingest fruits (Stevenson et al, 1994).…”