SPATIAL AND TEMPORAL DISTRIBUTION OF TWO <i>Anacroneuria</i> SPECIES (PLECOPTERA: PERLIDAE) IN A NEOTROPICAL RIVER OF COLOMBIA

Ecological studies on habitat use patterns on the distribution of Plecoptera species facilitate understanding its population dynamics. Our objective was to determine the distribution and abundance of Anacroneuria caraca Stark, 1995 and A. marta Zúñiga and Stark, 2002 in different microhabitats in the Gaira River during an annual hydrological cycle. Species were identified according to a nymph-adult association based on the male genitalia of mature and pre-emergent nymphs. Univariate analyses were performed to compare the abundance of the two species during the samplings and microhabitats. The greatest abundance of both species and the greatest number of pre-emergent nymphs were observed during the dry season and the beginning of the rainy season. Differences were not found in species abundances between samplings or microhabitats (p > 0.05); however, A. marta presented the highest abundance in the study. Regarding microhabitats, the highest abundance was recorded in the leaf litter with 638 individuals, while similar values were observed in the slow current pool and riffle with 194 and 294 individuals, respectively. This study showed that the leaf litter microhabitat is one of the most important Gaira River niches to both studied species. Additionally, the similar abundance of the two species in the leaf litter may suggest the availability of sufficient resources (food and refuge) and the superposition of niches between them.