Chironomids colonization on Nymphaea ampla L. detritus during a degradative ecological succession experiment in a Brazilian coastal lagoon

GONÇALVES JR., J.F.^{1 , 2}; ESTEVES, F.A.² & CALLISTO, M.¹

¹ Present address: Federal University of Minas Gerais, ICB, Dep. General Biology, Lab. Ecology of Benthos, P.O. Box. 486, 30.161-970, Belo Horizonte, MG, Brazil. e-mail jfjunior@icb.ufmg.br

² Federal University of Rio de Janeiro, CCS, IB, Dep. Ecology, Lab. of Limnology, P.O. Box 68020, 21941- 590, Rio de Janeiro, RJ, Brazil.

ABSTRACT: The objective of this study was to evaluate the colonization of Chironomidae larvae assemblage throughout the process of degradative ecological succession of detritus of Nymphaea ampla L. The experiment was performed at the littoral zone of the Jurubatiba coastal lagoon, Parque Nacional da Restinga de Jurubatiba, Macaé, State of Rio de Janeiro, Brazil. The colonization was followed through 16 days of an “in situ” experiment. During this 16 days period the detritus decomposed c. 90%. Nine genera from the Tanypodinae and the Chironominae were identified and Rheotanytarsus had the highest density (590 ind/100g DW). The predominant functional trophic group found among the Chironomidae genera was the collector-gatherers. The role of the Chironomidae larvae on the processes of aquatic macrophyte decomposition and degradative ecological succession of N. ampla was discussed. It was observed that the unstable substrate colonization leads to a decrease in density and diversity of the Chironomidae larvae.

Key-words: aquatic macrophytes, Chironomidae, detritus, decomposition, Nymphaea ampla .