How to evaluate the potential occurrence of intraguild predation

Abstract

Intraguild predation is the combination of exploitative competition and predation among potential competitors that use similar resources. It has the potential to shape population dynamics and community structure. Although there is much empirical evidence for the occurrence of intraguild predation in natural ecosystems, the study of its effects is mainly limited to short-term microcosm experiments. There is, therefore, certain skepticism about its actual significance in nature. A relevant concern is that there is no consensus regarding criteria to evaluate the possible occurrence of intraguild predation in short-term experiments, and methodological differences may therefore underlie apparent inconsistencies among studies. Our purpose here was to evaluate existing criteria to offer guidance for the design of experiments to determine whether two species may potentially engage in intraguild predation. The criteria are based on the condition that intraguild predators need to experience immediate energetic gains when feeding on the intraguild prey. Thus, a relevant experimental design must quantify predation but also fitness benefits of feeding on the other species, i.e. increases in reproduction, somatic growth, or survival.

The return of the trophic chain: fundamental vs realized interactions in a simple arthropod food web

“…For instance, Cancer productus, a crab native to the Northwest Pacific, consumes equal amounts of native oysters and of invasive drill oysters when each type of prey is offered alone, but when they are offered together crabs interact with the native oyster species only(Grason & Miner 2012). Therefore, if trophic links are not evaluated in presence of all species in the community, one may reach erroneous conclusions on the strength of the interaction(Guzmán et al 2016b;Fonseca et al 2017) and…”

Reciprocal intraguild predation and predator coexistence

“…Likewise, the oviposition by E. concordis was also significantly higher in the presence of juvenile I. zuluagai than without food (Figure b, GLM, χ 2 = 4.3, df = 1, p = 0.04). Together, this shows that the two species are involved in reciprocal intraguild predation (Fonseca et al., ).…”

“…Intraguild predation does not only involve killing individuals of the competing species, but also feeding on it (Polis et al., ), which can be observed directly, or can be inferred from increased survival, reproduction or development due to the feeding on the competitor (Fonseca et al., ). When this is not the case, the interaction should be classified as interspecific killing, an extreme form of interference competition (Fonseca et al., ). The previous experiment showed some indications that the IG‐predators benefitted from feeding on IG‐prey.…”

“…TA B L E 1 Co-occurrence of the predatory mites E. concordis and I. zuluagai on Jatropha curcas plants in the field that the two species are involved in reciprocal intraguild predation (Fonseca et al, 2017).…”

Asymmetric intraguild predation of Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) on a native Coccinellidae guild

“…However, a non-native predator would also interact with competitors and predators (top predators). As predator community dynamics are thought to be based on negative interactions, such as intraguild predation (IGP) (the killing and eating of species that use similar, often limiting, resources and are thus potential competitors - Polis et al (1989)), non-native predators growth rate would constrained by such interactions promoting coexistence (Polis et al, 1989;Hin et al, 2011;Fonseca et al, 2017). But, when the non-native predator did not suffer a negative effect from a native predator (enemy release hypothesis), either by absence or ineffectiveness of a top predator, or by a competitor it would not be controlled and the structure of this system could be destabilized (Crowder and Snyder, 2010;Björklund et al, 2016;Roy et al, 2016).…”