Caracterización trófica de Orestias (Teleostei: Cyprinodontidae) en el Parque Nacional Lauca

Abstract

RESUMENLos peces muestran una amplia diversidad de comportamientos alimentarios, algunas veces asociados con morfologías específi cas, las cuales pueden refl ejar adaptaciones para usar los recursos dependiendo de su hábitat. En los sistemas acuáticos aislados, los peces son un buen modelo de estudio para entender las relaciones trófi cas. Este estudió evaluó la dieta de cinco especies de Orestias, las cuales habitan ocho sitios diferentes en la Región de Arica y Parinacota, Parque Nacional Lauca. Se analizaron 177 estómagos pertenecientes a las especies Orestias chungarensis, O. laucaensis, O. parinacotensis, O. piacotensis y Orestias cf agassii. Para los análisis se utilizaron descriptores cuantitativos de número de items presa y frecuencia de ocurrencia. Se analizó la riqueza, diversidad y abundancia de presas por especies y localidad, se evaluó la amplitud y sobrelapamiento de dieta y mediante un análisis de correspondencia (DCA) se analizó la composición dietaria.En general, la dieta de Orestias consistió en zooplancton y macroinvertebrados asociados a las macrófi tas como son Cladocera (Chydorus, Daphnia, Alonella), Ostracoda (Cyprinotus). Amphipoda (Hyalella), Mollusca (Biomphalaria) e Insecta (Chironomus). La variación en la riqueza de presas y amplitud de dieta observado entre las poblaciones de Orestias sería el refl ejo de una estrategia oportunista de las especies, consumiendo las presas de mayor frecuencia, no observándose diferenciación trófi ca entre ellas. PALABRAS CLAVES:Altiplano, alopatría, dieta, peces, simpatría. ABSTRACTFish exhibit a wide diversity of feeding behaviors, sometimes associated with specifi c morphologies, which may refl ect adaptations to exploit the resources depending upon where they live. In isolated aquatic systems, fi sh provide a good model to study species trophic relationships. The present study evaluates the diet of fi ve species of Orestias which inhabit eight different sites of the Arica and Parinacota Region,Lauca National Park, Chile. We analyzed 177 stomachs of Orestias chungarensis, O.laucaensis, O.parinacotensis, O. piacotensis and Orestias cf agassii. For the analyses we used quantitative descriptors of number of prey items and frequency of occurrence. We analyzed the richness and abundance of prey,diet overlap by species and by location. We analyzed diet composition using an analysis of correspondence (DCA). The diet of Orestias consisted of zooplankton and macroinvertebrates associated with macrophytes such as Cladocera (Chydorus, Daphnia, Alonella), Ostracoda (Cyprinotus). Amphipoda (Hyalella), Mollusca (Biomphalaria) and Insecta (Chironomus). The variation in prey richness and diet amplitude observed among the studied populations of Orestias may refl ect an opportunist trophic strategy of these species, consuming the prey species which are most frequent, thus no showing trophic differentiation among them.

Pattern of genetic differentiation of an incipient speciation process: The case of the high Andean killifish Orestias

“…The short time since the events that originated this process has not allowed a complete lineage sorting among these populations in spite of the morphological differences that have been described and that motivated the description of different nominal species. In spite of the genetic and phylogeographic differentiation detected in this study, up to now there is no evidence of reproductive isolation among the groups and they do not appear to have developed ecological specialization, at least not at the trophic level [ 43 ]. There are also indications that individuals of these groups could maintain contact in the Parinacota wetland by sporadic migrations.…”

“…Recent trophic studies of Orestias in the LNP watersheds showed low prey richness and dietary range, which was related to the reduced size and shallow depth of these systems, with mostly microinvertebrates inhabiting the macrophyte belt. Thus, the local populations of Orestias showed similar dietary habits associated with prey availability [ 42 , 43 ].…”

Seasonal and depth variations in diet composition and dietary overlap between three native killifish of an emblematic tropical-mountain lake: Lake Titicaca (Bolivia)

“…Lower values than 0.60 are considered as a specialized diet using a low resource number, and values above 0.60 as a generalist (Krebs, 1999). Pianka’s symmetric index (1974) was measured to estimate the niche overlap in the diet composition between each species, depth and season (Guerrero et al , 2015). It is considered a biologically significant overlap when the value of this index exceeds 0.6 (Pianka, 1974).…”

Trophic Ecology of Endemic Andean Killifish (Orestias Species Complexes): A Review

“…Finally, the results of diet of five species of Orestias which inhabit eight different sites of the Arica and Parinacota Region, Lauca National Park, Chile. Show a pooled diet [39].…”