Abstract
Divergent natural selection is often believed to be the driving force behind phenotypic differentiation in characters related to resource acquisition, leading to trophic polymorphism in fishes. Here we use variation in the fatty acid composition of adipose and muscle tissues to look at differences in resource use by two recently described sympatric morphs of Percichthys trucha, a common freshwater fish of the Andean and Patagonian regions of South America. Because dietary fatty acids are often stored in carnivorous animals with little modification after consumption, they can be used to infer information about dietary habits of individuals. We found that the two morphs differed in the overall composition of fatty acids in both adipose and muscle tissue, but that there were some differences in how the morphs differed in lakes from the northern vs southern part of the range. Furthermore, we found that certain fatty acids were correlated with diet as determined by gut content analysis. Consumption of anisopteran larvae was highly correlated with 14:0 in adipose and muscle tissue; and higher levels of longer chain unsaturated fatty acids (i.e. 20 and 22 carbons) were correlated with the presence of fish and also amphipods in the diets. Taken together, the results suggest that there are marked differences in the foraging ecology of the two morphs of P. trucha inhabiting southern Andean lakes. (C) 2000 The Linnean Society of London.
| Original language | English |
|---|---|
| Pages (from-to) | 599-616 |
| Number of pages | 18 |
| Journal | Biological Journal of the Linnean Society |
| Volume | 69 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2000 |
Bibliographical note
Funding Information:We thank Miguel Battini and Amalia Denegri (Universidad Nacional del Comahue) for logistical support while conducting much of the fieldwork. Fieldwork was also all the more enjoyable with the contributions by Violeta Ruzzante and Pascal and Sacha Walde Ruzzante. We especially thank Claudio Chehébar and Pablo Martinez of the ‘Dirección Técnica de Parques Nacionales’ for permission to collect native fish within the Parques Nacionales Nahuel Huapi and Lanín. We also acknowledge the laboratory assistance of Shelley Lang. S.J.W. was supported by an Organization of American States fellowship while conducting the fieldwork. Funds for the fieldwork were provided by an NSERC (Canada) grant to S.J.W., and by Universidad Nacional del Comahue, CONICET (Argentina) and Agencia Nacional de Promoción Científica y Tecnológica (ANPCYT, Argentina) grants. Funds for laboratory work and analyses were provided by NSERC (Canada) operating and equipment grants to S.J.I.
ASJC Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
