Interaction between hunting strategy, habitat type and stratum drive intraguild predation and cannibalism

Abstract

Intraguild predation (IGP) is a common interaction between generalist predators when they competitively exploit similar resources and prey on each other. Theoretical models predict limitations for intraguild predator coexistence unless some mechanisms, such as the utilization of alternative prey (i.e. trophic niche partitioning) and cannibalism, increase the relative intraspecific clustering and interspecific segregation. As hunting strategies determine trophic niches of predators and their own vulnerability to predation, the hunting strategies may also determine the relative importance of cannibalism, predation, and exploitative competition and consequently the intensity of IGP. The importance of hunting strategies on the potential outcome of IGP and how habitat properties modify the interaction between hunting strategies remain poorly understood. Using published data on spider prey of spider predators, we first investigated how predation of a top-predator on a mesopredator is determined by the functional distance between both predators to understand how predation and exploitation are distributed in spider communities. Subsequently, we investigated the predation among spiders with particular hunting strategies to understand which strategies interact most frequently. We also investigated whether the interaction between hunting strategies was influenced by habitat type (forest, open (semi)natural habitat, agroecosystem) or by habitat stratum (ground versus vegetation). The hunting strategies of top-predators and mesopredators interacted to determine the relative capture proportions of conspecifics and hetero-specifics. This interaction was further modified by habitat type and stratum. Two mechanisms can reinforce coexistence in highly diverse spider communities. First, top-predators preyed most frequently on functionally distinct mesopredators, which indicates the overall intensity of IGP may be relaxed by a balanced Interaction between hunting strategy, habitat type and stratum drive intraguild predation and cannibalism

Pattern of seasonal variation in rates of predation between spider families is temporally stable in a food web with widespread intraguild predation

“…These channels appear only weakly connected via IGPrey, as just ~10% of direct spider-spider interactions involved spiders from the other channel. This pattern appears to contrast with a recent meta-analysis that documented much-higher rates (sometimes > 50%) of reciprocal predation between cursorial and web-spinning spiders [ 47 ]. This possible inconsistency merits some explanation.…”

An experimental framework for quantifying the degree of intraguild predation in omnivorous food webs in the field

“…One of such systems is agricultural systems, in which IGP occurs frequently (Polis et al, 1989;Rosenheim et al, 1995), and the food webs are generally less complex compared to most natural ecosystems. Furthermore, understanding the degree of IGP in agricultural field can provide useful implications for practitioners, for example, evaluating the effectiveness of biocontrol agents in pest control programs (M€ uller & Brodeur, 2002).…”

“…The framework can be implemented along environmental gradients or under different field treatments to investigate how various abiotic and biotic factors affect IGP interactions in a given food web type (e.g., arthropod food web). For instance, researchers can quantify and compare the degree of IGP across altitudes to examine whether omnivory patterns change with temperature, precipitation, or vegetation (Michalko et al., 2022). Moreover, besides the given spider top predator example, the framework applies to other generalist predators as well, provided that they are amenable to feeding trials and available for collection in the field.…”

“…Intraguild predation (IGP) is common in natural and humanmanaged ecosystems (Arim & Marquet, 2004;M€ uller & Brodeur, 2002;Polis & Holt, 1992) and has been documented across a wide range of predator taxa (Gagnon et al, 2011;Polis et al, 1989). IGP could substantially affect the abundance and distribution of interacting species, alter food web dynamics, and influence biodiversity and ecosystem functioning (Polis et al, 1989;Wang et al, 2019).…”

Importance of spider prey for development of a specialized araneophagous predator (Araneae: Palpimanidae)

“…https://doi.org/10.1636/JoA-S-22-017 Araneophagy, i.e., the capture and consumption of spider prey, is a common feeding strategy in many spider species (e.g., Michalko et al 2022). In several spider genera, such as Eriauchenius O. Pickard-Cambridge, 1881 (Archaeaidae), Ero C. L. Koch, 1836 and Mimetus Hentz, 1832 (both Mimetidae), Chorizopes O. Pickard-Cambridge, 1871 (Araneidae), Cyrba Simon, 1876 and Portia Karsch, 1878 (both Salticidae), and Lampona Thorell, 1869 (Lamponidae), araneophagy is the predominant feeding strategy (Peka´r & Toft 2015;Peka´r et al 2017).…”