Variaciones espaciales y ontogenéticas en la dieta de un plecóptero de amplia distribución Claudioperla tigrina Klapálek (Plecoptera: Gripopterygidae)
Revista e Biología Tropical
Organization for Tropical Studies
Año: 2016 vol. 65
Spatial and ontogenetic variations in the diet of a widely distributed stoneflyClaudioperla tigrina Klapálek (Plecoptera: Gripopterygidae). Dietary information gives insight into several ecological processes acting on lotic ecosystems. This work aims: 1) identify immature Claudioperla tigrina dietary habits from samples collected in a wide altitudinal and latitudinal gradient in Argentina; 2) assigned to the functional feeding group (FFG) of C. tigrina from gut content analysis and the study of the morphology of mouthparts; 3) evaluate differences in diet in the sites studied. Nymph studied include different developmental stages (four size classes) and were collected along a wide spatial range of northwestern Argentina. The ingested material was extracted from the foregut and midgut by using ventral dissection of thorax. Dietary profiles were analyzed through the estimation of parameters Dirichlet-multinomial distribution. ANOVAS´s were made for each food item according to the sites. Multidimensional Scaling was used to identify sites with similar dietary profiles. Mouthparts are similar in the different size classes, except for an increase of the sclerotization with age. Mouthparts do not greatly diverge from a typical chewing groundplan, presenting relatively short labial and maxillar palps, and strong, sclerotized and denticulated mandibles and maxillae. Our results showed that the nymphs of C. tigrina ingest two or more food items (MOPGCPOM, FPOM, invertebrates and algae), suggesting that it has a flexible diet. The diet changes in relation to body size, in the early stages finer particles are consumed, while in the final stages the particles are larger. Dominant dietary item is gross coarse particulate organic particulate matter, with signals of shredding during ingestion. Significant differences in the quantity of secondary items were found, that may relate with environmental offer availability in the different ecoregions analyzed. The FFG of Claudioperla tigrina is primarily shredder, with a secondary assignation to collector-gatherer (of fine particulate organic matterFPOM) in Yungas Forest and Humid Grasslands, but to predator in High Andes. FFG classification of C. tigrina and the definition of their role of processing organic matter is an important step for future studies of food webs and other methodologies based on functional groups.