<b>Fauna structure of water mites associated with <em>Eichhornia azurea</em> in two lakes of the upper Paraná floodplain, Mato Grosso do Sul State, Brazil</b> - DOI: 10.4025/actascibiolsci.v27i4.1268

Abstract

The density and distribution of mites in different sections of the stolon of Eichhornia azurea were studied monthly for 13 months in two upper Paraná River floodplain lakes. The fluviometric variation and consequent changes in the concentrations of dissolved oxygen in the shallow water phase were shown by PCA. DCA showed the mites distribution in the plant sections, forming 5 groups: group A formed by Centrolimnesia, group B formed by Unionicola, Koenikea, Neumania, Piona and nymphs, group C by Arrenurus and group E formed by Hydrodroma and Hydrozetes. The mites of groups A, C, and E presented high density in the apical and intermediary sections; therefore, the specimens were less tolerant of the low concentrations of oxygen. Groups B and D were represented by specimens adapted to the bottom and tolerant of hypoxic conditions, where high density in the basal segment was registered. The rise in the water level favored the occurrence of mites in agglomerations on Eichhornia azurea in function of the depletion of oxygen in deep areas of the lakes and through the increase of hosts and prey. Temporal variation in mite density was related to the density of available prey, while vertical variation in the segment was diet specific and some specimens were tolerant to hypoxic conditions