Microalgae trapped by carnivorous bladderworts (Utricularia, Lentibulariaceae): analysis, attributes and structure of the microalgae trapped

摘要

Utricularia species capture small prey in traps. The prey spectrum of aquatic Utricularia species includes a large variety of organisms (e.g. copepods, cladocerans, crustacea, rotifers, algae). This study focuses on selected attributes (species richness, density, biovolume, C and N contents) of microalgae captured inside the traps of aquatic Utricularia spp.. A total of 850 traps of four aquatic bladderwort pecies (Utricularia australis, U. foliosa, U. gibba and U. vulgaris) from tropical (Ivory Coast) and temperate (Canada, Germany) regions has been investigated concerning the algae captured. In total, 302 microalgal taxa have been identified with Bacillariophyceae, Chlorophyceae and Charophyceae being most species rich. The number of microalgae species captured was different among the Utricularia spp. It was relatively low inside the traps of U. gibba and U. foliosa from tropical Africa, with the greatest species diversity observed within the Charophyceae (Desmidiaceae). The highest microalgae density, biovolume, C and N contents were observed within the traps of U. gibba/IC. There are considerable differences in the amount and composition of algae trapped among the Utricularia spiecies. The amount of microalgae captured does not relate to trap size parameters (length, height and volume).