Intraguild Predation Among Aphid Predators: Characterization and Influence of Extraguild Prey Density

Abstract

Intraguild predation (IGP), a common interaction in invertebrates and vertebrates, affects the abundance and distribution of many species. Several parameters influence the magnitude and direction of IGP: feeding specificity, size, mobility, and aggressiveness of the protagonists, as well as extraguild prey density. Under laboratory conditions, we studied IGP among three species of aphid predators, Aphidoletes aphidimyza (Diptera: Cecidomyiidae), Chrysoperla rufilabris (Neuroptera: Chrysopidae), and Coleomegilla maculata lengi (Coleoptera: Coccinellidae), which commonly attack the potato aphid (extraguild prey) Macrosiphum euphorbiae (Homoptera: Aphididae). We characterized the levels and symmetry of IGP among the various stages of the predators in the absence of extraguild prey. The aphid specialist A. aphidimyza was more vulnerable to IGP than C. rufilabris and C. maculata, two generalist predators. The C. maculata/C. rufilabris interaction was symmetric (mutual IGP), whereas the C. maculata/A. aphidimyza and C. rufilabris/A. aphidimyza interactions were asymmetric, in favor of the coccinellid and the lacewing, respectively. Sessile and low mobility stages of all species were extremely vulnerable to IGP. Generally, the larger sized individual won confrontations. For similar sizes, lacewing larvae were superior to coccinellid larvae.We also tested whether IGP decreases when extraguild prey are introduced into the system. Data from five predator combinations revealed three types of responses: (1) an exponential decrease in IGP (lacewing instar I vs. coccinellid instar I); (2) a constant IGP (lacewing instar III vs. coccinellid instar I); (3) a constant IGP at low densities decreasing at high densities (lacewing instar III vs. gall midge old larva). Four theoretical scenarios are derived from these responses. Each is discussed according to the ecological attributes of the protagonists. This study shows that IGP is influenced by factors inherent to the predators and external factors such as extraguild prey density. The results are discussed further in the context of aphid biological control.

Spiny Prey, Fortunate Prey. Dorsal Spines Are an Asset in Intraguild Interactions among Lady Beetles

“…In the pupae, the dense hair cover acts as a protection against ants. The main threats to coccinellid larvae may come from species that exploit the same resources, such as heterospecific coccinellids (Agarwala and Dixon, 1992;Obrycki et al, 1998), syrphids (Hindayana et al, 2001), chrysopids (Sengonca and Frings, 1985;Lucas et al, 1998;Phoofolo and Obrycki, 1998), and pentatomids (Mallampalli et al, 2002;De Clercq et al, 2003). However, little predation has been directly observed toward H. axyridis larvae except by coccinellid larvae Ware and Majerus, 2008) or by the pentatomid bug Podisus maculiventris (Say) (De Clercq et al, 2003).…”

“…We choose to confront third H. axyridis larval instars and fourth C. septempunctata instars to provide these latter with an advantage in terms of body size (Wissinger, 1992;Snyder and Hurd, 1995;Lucas et al, 1998;Woodward and Hildrew, 2002). This unbalanced situation is not unrealistic as it occurs under field conditions because of the later arrival of H. axyridis, generating in this latter species an obvious need for maximal defenses against older IG-predators.…”

Mixed release of two parasitoids and a polyphagous ladybird as a potential strategy to control the tobacco whitefly Bemisia tabaci

“…One positive feature claimed for mixed releases is that employing multiple natural enemies with different feeding patterns could ensure continued suppression of a target pest throughout its lifecycle. However, natural enemy diversity could also result in limited or reduced pest control as a result of interactions including interspecific competition, guild predation, or super parasitism among multiple biological control agents10111213141516.…”

When Herbivores Eat Predators: Predatory Insects Effectively Avoid Incidental Ingestion by Mammalian Herbivores

“…Dropping off the plant is sometimes used by coccinellid larvae as a defense mechanism against intraguild predation by lacewings and other coccinellid beetles [36], [37]. This type of response is instar-specific, as smaller instar larvae are more easily captured and eaten and therefore drop to the ground more readily when an arthropod predator attempts to catch them [38].…”