کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1975696 1060647 2010 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Stable isotopes document mainland–island divergence in resource use without concomitant physiological changes in the lizard Liolaemus pictus
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Stable isotopes document mainland–island divergence in resource use without concomitant physiological changes in the lizard Liolaemus pictus
چکیده انگلیسی

Shifts in feeding ecology are believed to promote island–mainland divergence. The lizard Liolaemus pictus has several different subspecies on Chilean islands and mainland. These subspecies inhabit contrastingly different habitats both in different islands and mainland, which suggests the potential for habitat related dietary variation. We investigated the dietary habits of L. pictus by both stomach content analyses and by nitrogen stable isotope analyses (δ15N), which we used as a proxy variable for trophic level. We also compared the morphology of the digestive tract and the activity of intestinal digestive enzymes of mainland and island lizards. We hypothesized differences in diet and trophic level among populations and that these differences would predict the expression of the morphological and biochemical features of the digestive tract. More specifically, we predicted shorter intestines and higher levels of peptidases in more insectivorous than in more frugivorous/herbivorous lizards. The diet of L. pictus was characterized by the consumption of a wide diversity of food types, including fruit and insects, in all populations. Stable isotopes revealed higher trophic level, and hence probably higher protein intake, in mainland than in island populations, but contrary to our prediction, they had shorter intestines and higher relative activity of intestinal peptidases than mainland lizards. Furthermore, the proportion of fruit items in the stomach content was higher in the population that exhibited the lowest tropic level. These results suggest that morphological and physiological differences among populations of L. pictus are not correlated with feeding ecology, suggesting that the lizard's first responses to the selective pressure represented by a diet shift are behavioral.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology - Volume 156, Issue 1, May 2010, Pages 61–67
نویسندگان
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