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Preference for cannibalism and ontogenetic constraints in competitive ability of piscivorous top predators.

Byström P, Ask P, Andersson J, Persson L - PLoS ONE (2013)

Bottom Line: Occurrence of cannibalism and inferior competitive ability of predators compared to their prey have been suggested to promote coexistence in size-structured intraguild predation (IGP) systems.The literature survey showed that piscivorous top consumers generally selected conspecifics over interspecific prey, and that prey species are competitively superior compared to juvenile piscivorous species in the zooplankton niche.We suggest that the observed selectivity for cannibal prey over interspecific prey and the competitive advantage of prey species over juvenile piscivores are common features in fish communities and that the observed selectivity for cannibalism over interspecific prey has the potential to mediate coexistence in size structured intraguild predation systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden. par.bystrom@emg.umu.se

ABSTRACT
Occurrence of cannibalism and inferior competitive ability of predators compared to their prey have been suggested to promote coexistence in size-structured intraguild predation (IGP) systems. The intrinsic size-structure of fish provides the necessary prerequisites to test whether the above mechanisms are general features of species interactions in fish communities where IGP is common. We first experimentally tested whether Arctic char (Salvelinus alpinus) were more efficient as a cannibal than as an interspecific predator on the prey fish ninespine stickleback (Pungitius pungitius) and whether ninespine stickleback were a more efficient competitor on the shared zooplankton prey than its predator, Arctic char. Secondly, we performed a literature survey to evaluate if piscivores in general are more efficient as cannibals than as interspecific predators and whether piscivores are inferior competitors on shared resources compared to their prey fish species. Both controlled pool experiments and outdoor pond experiments showed that char imposed a higher mortality on YOY char than on ninespine sticklebacks, suggesting that piscivorous char is a more efficient cannibal than interspecific predator. Estimates of size dependent attack rates on zooplankton further showed a consistently higher attack rate of ninespine sticklebacks compared to similar sized char on zooplankton, suggesting that ninespine stickleback is a more efficient competitor than char on zooplankton resources. The literature survey showed that piscivorous top consumers generally selected conspecifics over interspecific prey, and that prey species are competitively superior compared to juvenile piscivorous species in the zooplankton niche. We suggest that the observed selectivity for cannibal prey over interspecific prey and the competitive advantage of prey species over juvenile piscivores are common features in fish communities and that the observed selectivity for cannibalism over interspecific prey has the potential to mediate coexistence in size structured intraguild predation systems.

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Attack rate (l s−1±1SE) of char (obtained from [31]) and ninespine stickleback when feeding on zooplankton (Daphnia sp.).
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pone-0070404-g003: Attack rate (l s−1±1SE) of char (obtained from [31]) and ninespine stickleback when feeding on zooplankton (Daphnia sp.).

Mentions: Comparison of zooplankton attack rate estimates of ninespine stickleback with previous estimates for small char, showed that ninespine stickleback was a more efficient zooplanktivore than char (ANCOVA, using body size as covariate, main effect F1,4 = 16.3, P = 0.016) (Fig. 3).


Preference for cannibalism and ontogenetic constraints in competitive ability of piscivorous top predators.

Byström P, Ask P, Andersson J, Persson L - PLoS ONE (2013)

Attack rate (l s−1±1SE) of char (obtained from [31]) and ninespine stickleback when feeding on zooplankton (Daphnia sp.).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3716608&req=5

pone-0070404-g003: Attack rate (l s−1±1SE) of char (obtained from [31]) and ninespine stickleback when feeding on zooplankton (Daphnia sp.).
Mentions: Comparison of zooplankton attack rate estimates of ninespine stickleback with previous estimates for small char, showed that ninespine stickleback was a more efficient zooplanktivore than char (ANCOVA, using body size as covariate, main effect F1,4 = 16.3, P = 0.016) (Fig. 3).

Bottom Line: Occurrence of cannibalism and inferior competitive ability of predators compared to their prey have been suggested to promote coexistence in size-structured intraguild predation (IGP) systems.The literature survey showed that piscivorous top consumers generally selected conspecifics over interspecific prey, and that prey species are competitively superior compared to juvenile piscivorous species in the zooplankton niche.We suggest that the observed selectivity for cannibal prey over interspecific prey and the competitive advantage of prey species over juvenile piscivores are common features in fish communities and that the observed selectivity for cannibalism over interspecific prey has the potential to mediate coexistence in size structured intraguild predation systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden. par.bystrom@emg.umu.se

ABSTRACT
Occurrence of cannibalism and inferior competitive ability of predators compared to their prey have been suggested to promote coexistence in size-structured intraguild predation (IGP) systems. The intrinsic size-structure of fish provides the necessary prerequisites to test whether the above mechanisms are general features of species interactions in fish communities where IGP is common. We first experimentally tested whether Arctic char (Salvelinus alpinus) were more efficient as a cannibal than as an interspecific predator on the prey fish ninespine stickleback (Pungitius pungitius) and whether ninespine stickleback were a more efficient competitor on the shared zooplankton prey than its predator, Arctic char. Secondly, we performed a literature survey to evaluate if piscivores in general are more efficient as cannibals than as interspecific predators and whether piscivores are inferior competitors on shared resources compared to their prey fish species. Both controlled pool experiments and outdoor pond experiments showed that char imposed a higher mortality on YOY char than on ninespine sticklebacks, suggesting that piscivorous char is a more efficient cannibal than interspecific predator. Estimates of size dependent attack rates on zooplankton further showed a consistently higher attack rate of ninespine sticklebacks compared to similar sized char on zooplankton, suggesting that ninespine stickleback is a more efficient competitor than char on zooplankton resources. The literature survey showed that piscivorous top consumers generally selected conspecifics over interspecific prey, and that prey species are competitively superior compared to juvenile piscivorous species in the zooplankton niche. We suggest that the observed selectivity for cannibal prey over interspecific prey and the competitive advantage of prey species over juvenile piscivores are common features in fish communities and that the observed selectivity for cannibalism over interspecific prey has the potential to mediate coexistence in size structured intraguild predation systems.

Show MeSH
Related in: MedlinePlus