Aspectos morfológicos e ecológicos do protista ciliado Rhabdostyla Chironomi Kahl, 1933 (Ciliophora, Peritrichia) epibionte de larvas de quironomídeos em um córrego urbano do sudeste do Brasil

Abstract

In the present study, both taxonomy and morphology aspects of the epibiont ciliate Rhabdostyla chironomi found in São Pedro stream (Juiz de Fora-MG), as well some ecological aspects of this epibiotic relationship between the peritrich and chironomid larvae from genus Chironomus gr. decorus. The present dissertation is divided into four parts. In the first one, a population ciliates from genus Rhabdostyla was isolated and investigated in vivo and using techniques of silver impregnation and scanning electron microscopy, being identify as a population of the the poorly know peritrich ciliate R. chironomi. In the second, was analyzed the spatial and temporal pattern of occurrence of R. chironomi as epibiont on Chironomus gr. decorus trough collections in the period of one year at five sampling stations at São Pedro Stream. Statistical analyses showed correlation between the prevalence of infestation and as rainfall, food availability and host abundance, besides the temporal and spatial heterogeneity of the ciliate. In the third one, was evaluated the influence of organic pollution in the distribution of R. chironomi on chironomid larvae, trough two experiments, the first one, made in five sampling stations, over a year of study and the second, was one collection in eight sampling stations in the same stream. The prevalence of infestation showed spatial heterogeneity occurring at stations with a higher degree of organic enrichment. In the fourth part, was investigated the colonization sites of R. chironomi as epibiont on chironomid larvae and also, quantified the colonization intensity of this relationship. All 26.104% of epibionts ciliates exclusively colonized the ventral tubules of the chironomid larvae. The colonization intensity ranged from one to 67 individuals per host, with mean intensity of 4.86 (± 1.5348) of which 91.03% had between one to ten ciliates.