INTRAGUILD PREDATION DRIVES EVOLUTIONARY NICHE SHIFT IN THREESPINE STICKLEBACK

Intraguild predation—competition and predation by the same antagonist—is widespread, but its evolutionary consequences are unknown. Intraguild prey may evolve antipredator defenses, superior competitive ability on shared resources, or the ability to use an alternative resource, any of which may alte...

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Bibliographic Details
Published in:Evolution 2012-06, Vol.66 (6), p.1819-1832
Main Authors: Ingram, Travis, Svanbäck, Richard, Kraft, Nathan J. B., Kratina, Pavel, Southcott, Laura, Schluter, Dolph
Format: Article
Language:English
Subjects:
Animals
Benthic invertebrates
Biological Evolution
Biomass
Character displacement
Comparative analysis
Cottus asper
Diet
Ecological competition
Ecological genetics
Evolution
Food webs
Gasterosteus aculeatus
geometric morphometrics
mesocosm experiment
Mortality
omnivory
Plankton
Predation
Predators
Predatory Behavior
Sculpin
Smegmamorpha - anatomy & histology
Smegmamorpha - genetics
Smegmamorpha - growth & development
Smegmamorpha - physiology
Zooplankton
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Summary:Intraguild predation—competition and predation by the same antagonist—is widespread, but its evolutionary consequences are unknown. Intraguild prey may evolve antipredator defenses, superior competitive ability on shared resources, or the ability to use an alternative resource, any of which may alter the structure of the food web. We tested for evolutionary responses by threespine stickleback to a benthic intraguild predator, prickly sculpin. We used a comparative morphometric analysis to show that stickleback sympatric with sculpin are more armored and have more limnetic-like body shapes than allopatric stickleback. To test the ecological implications of this shift, we conducted a mesocosm experiment that varied sculpin presence and stickleback population of origin (from one sympatric and one allopatric lake). Predation by sculpin greatly increased the mortality of allopatric stickleback. In contrast, sculpin presence did not affect the mortality of sympatric stickleback, although they did have lower growth rates suggesting increased nonpredatory effects of sculpin. Consistent with their morphology, sympatric stickleback included more pelagic prey in their diets, leading to depletion of Zooplankton in the mesocosms. These findings suggest that intraguild prey evolution has altered food web structure by reducing both predation by the intraguild predator and diet overlap between species.
ISSN:0014-3820
1558-5646
1558-5646
DOI:10.1111/j.1558-5646.2011.01545.x