The invertebrate colonization during decomposition of Eichhornia azurea was observed in a lateral lake in the mouth zone of Paranapanema River into Jurumirim Reservoir in two periods of the year. The litter bags method was used for measuring the decomposition rate as well as to evaluate the invertebrates colonization. Forty-two litter bags, measuring 15 × 20 cm in size and 2 mm mesh net, were incubated "in situ". Six litter bags (three for colonization and three for decomposition measurements) were removed after the 1 st , 3 rd , 7 th , 14 th , 28 th , 56 th and 72 nd days of incubation. After each day, the material was carefully cleaned for detritus removal and invertebrate sampling. The biological material was fixed with 4% formaline and then sorted and identified. The remaining plant material was dried in an oven (at 60 o C) and weighed. A fast material loss occurred during the first 24 hours and the decomposition rate was higher during the rainy season than in the dry season. A peak on invertebrate density (110 ind.g.DW -1 ) on the remaining detritus of Eichhornia azurea was recorded in the 56 th day of dry season, when the polyphenol concentration of plant detritus was 0.57 UDO.g.DW -1 . In the rainy season, higher density was found in the 28 th day of incubation, when the polyphenol concentration was 4.36 UDO.g.DW -1 . Apparently, the reduction in the polyphenol concentration was followed by an increase in invertebrate densities. The majority of the species observed in the detritus belongs to the collector group that was dominant after the 7 th and 14 th days in the rainy and dry seasons, respectively.Key words: decomposition, colonization, invertebrate, Eichhornia azurea, lake.
RESUMO Decomposição de Eichhornia azurea e colonização por invertebradosA colonização por invertebrados durante o processo de decomposição de Eichhornia azurea foi examinada em duas épocas do ano na zona de desembocadura do Rio Paranapanema,