The Case for Omnivory: Intraguild Predation of Plant-Dwelling Arthropods by Large Mammalian Herbivores

Abstract

Intraguild predation (i.e., when two organisms that share resources, such as food and habitat, kill or eat one another) is a form of interspecific competition described by Polis et al. (1989) and observed by ecologists in various ecosystems between predators of overlapping niches. However, it has only recently been studied and substantiated in herbivores due to its cryptic nature (Berman & Inbar, 2022) and remains to be analyzed in wild LMH. Using DNA metabarcoding as a method of dietary analysis in DNA extracts of fecal samples of ten mammalian species collected from Gorongosa National Park (PNG) in Mozambique, this study evaluates occurrences of intraguild predation of plant-dwelling arthropods (PDA) by large mammalian herbivores (LMH) in evaluation of two competing hypotheses; (1) the obligate herbivore hypothesis which predicts no evidence for intraguild predation and (2) the coincidental IGP hypothesis which predicts incidental ingestion of PDA by LMH. Results do not support either hypothesis, but instead show evidence for non-incidental intraguild predation of PDA by LMH, with considerable variation by LMH species. Future work remains in quantifying PDA ingestion and expanding analysis to a wider range of LMH species in order to continue increasing awareness of LMH diets and nutritional needs.