INVESTIGADORES
CUSSAC Victor Enrique
artículos
Título:
Trophic polymorphism, habitat and diet segregation in Percichthys trucha (Pisces: Percichthyidae) in the Andes
Autor/es:
RUZZANTE, D.E.; S.J. WALDE; V.E. CUSSAC; P.J. MACCHI; M.F. ALONSO
Revista:
BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY
Referencias:
Año: 1998 vol. 65 p. 191 - 214
ISSN:
0024-4066
Resumen:
Divergent natural selection affecting specific trait combinations that lead to greater efficiency
in resource exploitation is believed to be a major mechanism leading to trophic polymorphism
and adaptive radiation. We present evidence of trophic polymorphism involving two benthic
morphs within Percichthys trucha, a fish endemic to temperate South America. In a series of
lakes located in the southern Andes, we found two morphs of P. trucha that could be
distinguished on the basis of gill raker length and five other morphological measures, most
of which are likely associated with the use of food resources. The differences were consistent
across all lakes examined, and were correlated with habitat use and diet. Individuals with
longer gill rakers were more abundant in the littoral zone (littoral morph) while the short
gill-raker morph was more abundant at 10m depth and deeper (deep benthic morph). Both
morphs fed primarily on benthic invertebrates, but the littoral morph fed more on larval
Anisoptera than did the deep benthic morph. Phenotypic correlations among traits were
high for the littoral morph, but low and non-significant for the deep-benthic morph. We
suggest that gill raker length may influence the relative efficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.ffecting specific trait combinations that lead to greater efficiency
in resource exploitation is believed to be a major mechanism leading to trophic polymorphism
and adaptive radiation. We present evidence of trophic polymorphism involving two benthic
morphs within Percichthys trucha, a fish endemic to temperate South America. In a series of
lakes located in the southern Andes, we found two morphs of P. trucha that could be
distinguished on the basis of gill raker length and five other morphological measures, most
of which are likely associated with the use of food resources. The differences were consistent
across all lakes examined, and were correlated with habitat use and diet. Individuals with
longer gill rakers were more abundant in the littoral zone (littoral morph) while the short
gill-raker morph was more abundant at 10m depth and deeper (deep benthic morph). Both
morphs fed primarily on benthic invertebrates, but the littoral morph fed more on larval
Anisoptera than did the deep benthic morph. Phenotypic correlations among traits were
high for the littoral morph, but low and non-significant for the deep-benthic morph. We
suggest that gill raker length may influence the relative efficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.Percichthys trucha, a fish endemic to temperate South America. In a series of
lakes located in the southern Andes, we found two morphs of P. trucha that could be
distinguished on the basis of gill raker length and five other morphological measures, most
of which are likely associated with the use of food resources. The differences were consistent
across all lakes examined, and were correlated with habitat use and diet. Individuals with
longer gill rakers were more abundant in the littoral zone (littoral morph) while the short
gill-raker morph was more abundant at 10m depth and deeper (deep benthic morph). Both
morphs fed primarily on benthic invertebrates, but the littoral morph fed more on larval
Anisoptera than did the deep benthic morph. Phenotypic correlations among traits were
high for the littoral morph, but low and non-significant for the deep-benthic morph. We
suggest that gill raker length may influence the relative efficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.P. trucha that could be
distinguished on the basis of gill raker length and five other morphological measures, most
of which are likely associated with the use of food resources. The differences were consistent
across all lakes examined, and were correlated with habitat use and diet. Individuals with
longer gill rakers were more abundant in the littoral zone (littoral morph) while the short
gill-raker morph was more abundant at 10m depth and deeper (deep benthic morph). Both
morphs fed primarily on benthic invertebrates, but the littoral morph fed more on larval
Anisoptera than did the deep benthic morph. Phenotypic correlations among traits were
high for the littoral morph, but low and non-significant for the deep-benthic morph. We
suggest that gill raker length may influence the relative efficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.fferences were consistent
across all lakes examined, and were correlated with habitat use and diet. Individuals with
longer gill rakers were more abundant in the littoral zone (littoral morph) while the short
gill-raker morph was more abundant at 10m depth and deeper (deep benthic morph). Both
morphs fed primarily on benthic invertebrates, but the littoral morph fed more on larval
Anisoptera than did the deep benthic morph. Phenotypic correlations among traits were
high for the littoral morph, but low and non-significant for the deep-benthic morph. We
suggest that gill raker length may influence the relative efficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.fficiency of suction feeding for the
two morphs. This is the first evidence of trophic polymorphism in fishes from temperate
South America.