Copépodos Notodiaptomus sp. Kiefer (Crustacea, Calanoida) naturalmente infectados com metacestódeos no reservatório do Juqueri, São Paulo, Brasil / Copepods Notodiaptomus sp. Kiefer (Crustacea, Calanoida) naturally infected by metacestodes in the Juqueri reservoir, São Paulo, Brazil

ABSTRACT

The aim of this work was to identify the components of zooplankton that act as intermediate hosts of cestodes. One hundred and ninety four copepods of the suborder Calanoida, 317 copepods of the suborder Cyclopoida and 4240 cladocerans were collected in the Juqueri reservoir, in the state of São Paulo, from January to August, 2003. Only Copepods Calanoida of the genus Notodiaptomus sp. Kiefer were found to be infected and contained two distinct forms of metacestodes. The metacestodes, denominated Met 1 (order Proteocephalidea) and Met 2 (order Cyclophyllidea), had the following rates of prevalence and mean intensities of infection Met 1 - 2.06 percent and 64 larvae/copepod and Met 2 - 0.52 percent and one larvae/copepod. The positive copepods were collected at the margins of the reservoir during the day. This finding suggest that parasitism may lead to a change in the behavior of the copepods and make them more susceptible to predation in shallow water.

RESUMO

Este trabalho teve o objetivo de identificar os componentes do zooplâncton que atuam como hospedeiros intermediários de cestódeos. Foram examinados 194 copépodos da subordem Calanoida, 317 copépodos da subordem Cyclopoida e 4240 cladóceros coletados no reservatório do Juqueri, Estado de São Paulo, entre janeiro e agosto de 2003. Apenas copépodos Calanoida do gênero Notodiaptomus sp. Kiefer encontravam-se positivos, sendo relatada duas formas morfológicas distintas de metacestódeos. Os metacestódeos, denominados Met 1 (Proteocephalidea) e Met 2 (Cyclophyllidea) apresentaram as seguintes prevalências e intensidades médias de infecção Met 1 - 2,06 por cento e 64 larvas/copépodo e Met 2 - 0,52 por cento e uma larva/copépodo. Os copépodos positivos foram coletados na região litorânea do reservatório durante o dia, o que leva a crer que o parasitismo pode modificar o comportamento dos copépodos tornando-os mais acessíveis à predação.