Selective predation of thecamoeba sphaeronucleolus (greeff, 1891) on filamentous algae in natural conditions

Abstract

Predation of algae by amoebae has been commonly reported in laboratory, but scarcely studied in natural ecosystems. Feeding selectivity and behavior of Thecamoeba sphaeronucleolus was studied from samples taken from a small eutrophic pond. Mougeotia sp. (77%) and Phormidium autumnale (12%) were the dominant algal species. P. autumnale was the most extensively predated algae by T. sphaeronucleolus, although both major algal species were similar in size. Cyanobacteria cell-wall structure and trichome flexibility, together with the capacity for gliding movement seem important to explain this selective predation. The two specific mechanisms for filaments ingestion by this amoeba are described. © 1994, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.