Importance of environmental productivity and diet quality in intraguild predation

In the intricate network of ecological interactions, intraguild predation emerges as a fundamental community module incorporating omnivory. Classical equilibrium theory predicts the exclusion of the intraguild predator and prey at low and high environmental productivity, respectively, with the coexistence of both species occurring only at intermediate productivity levels. However, empirical studies challenge this theoretical prediction, particularly concerning the extinction of intraguild prey in highly productive environments. To address this enigmatic issue, Diehl (2003), Abrams and Fung (2010a) explore the impact of food quality and propose that low nutritional quality of the basal resource stabilizes omnivorous systems. Yet, the influence of intermediate consumer quality remains inadequately explored. This study employs analytical and numerical bifurcation studies to investigate the effects of the quality of two diet types. Various bifurcations, including supercritical and subcritical Hopf bifurcations, saddle-node bifurcations of periodic solutions, and transcritical bifurcations of periodic solutions are observed. These bifurcations are directly linked to the destinies of intraguild prey and predators. The results reveal that, in highly productive environments, it may not be the intermediate consumer but the omnivore that faces extinction. This discovery holds significant implications for the conservation and management of omnivorous systems.