Keywords :
Feeding habit; Diet; Prey selection; Capture; Predation; Predatory performance; Trophic polyphenism; Resource partitioning; Trophic specialization; Size-selective predation; Gape size; Functional morphology; Mouth opening; Labial folds; Plankton; Fairy shrimp; Metamorphosis; Heterochrony; Facultative paedomorphosis; Polyphenism; Polymorphism; Lac de la cabane; Alpine newt; Mesotriton alpestris; Triturus alpestris; Ichthyosaura alpestris; Triton alpestre; Amphibien; Succès prédateur
Abstract :
[en] The feeding performances of two heterochronic morphs of the Alpine newt Triturus alpestris were investigated in laboratory experiments. Although both morphs are able to feed in the aquatic habitat, the hydrodynamics of prey capture differ between morphs. In paedomorphs water sucked with prey is expelled behind the mouth through gill bars. In metamorphs, water is expelled by the mouth as gill slits are closed. Feeding performance was better in paedomorphs than in metamorphs when foraging on aquatic crustaceans, but paedomorphs were less successful when foraging on terrestrial invertebrates caught at the water surface. These differences in prey capture success related to prey type allow the two morphs to use specific resources in their aquatic habitat. These results are consistent with previous studies that showed diet differentiation between morphs in natural populations. Such resource partitioning is a factor favouring the maintenance of facultative paedomorphosis in natural populations.
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