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Article Dans Une Revue Ecological Entomology Année : 2019

Prey size and predator density modify impacts by natural enemies towards mosquitoes

La taille des proies et la densité des prédateurs modifient les impacts des ennemis naturels sur les moustiques

Résumé

Interactions between multiple predators can modify prey risk through its ontogeny and profoundly alter ecological community. Understandings of these biotic factors are important for robust quantifications of natural enemy effects on target species, yet their combined influence lacks investigation. 2. We used functional responses (FRs) to quantify the predatory impacts of Notonecta glauca water boatman; Ng) and Gammarus pulex (river shrimp; Gp) towards four different larval instars of Culex pipiens in container-style habitats. Using conspecific pairs of predators, we examined multiple predator effects (MPEs) of both predator species across larval prey size, and applied prey preference tests to examine prey selectivity across predator-prey body size ratios. 3. Both predators were able to feed on C. pipiens larvae across their larval ontogeny, however, Ng consumed significantly greater larvae than Gp. Functional responses of Ng were typically Type IIs, whilst Gp trended towards sigmoidal Type IIIs. Predation by pairs of Ng and Gp showed independent MPEs towards first, third and fourth instar (except predation by Gp at higher densities of fourth instar) stages, while for second instar stages Ng showed synergistic MPEs and Gp showed antagonistic MPEs. Both predators preferred late instar mosquitoes (Ng: fourth instar; Gp: third instar). These preferences reflected predator:prey weight-length ratios, showing that relative sizes of predators and prey are important factors in prey selectivity. 4. Our results demonstrate that multiple predator effects, combined with intraspecific prey preferences, may modulate trophic interactions within ecosystems. Therefore, such effects should be increasingly considered to further understandings of agent efficacies.

Dates et versions

hal-02609881 , version 1 (16-05-2020)

Identifiants

Citer

A. Dalal, R.N. Cuthbert, J.T.A. Dick, Arnaud Sentis, C. Laverty, et al.. Prey size and predator density modify impacts by natural enemies towards mosquitoes. Ecological Entomology, 2019, ⟨10.1111/een.12807⟩. ⟨hal-02609881⟩
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