Colonization by Chironomidae Larvae in Decomposition Leaves ofEichhornia azureain a Lentic System in Southeastern Brazil

Lidimara Souza Da Silveira,Roberto Da Gama Alves,Danielle Pinheiro Lobo,Guilherme Augusto Da Silveira,Renato Tavares Martins,Richard Michael Grazul

doi:10.1673/031.013.2001

Lidimara Souza Da Silveira, Roberto Da Gama Alves + Show 4 more

Open Access

https://doi.org/10.1673/031.013.2001

Copy DOI

Abstract

The objective of this study was to analyze the colonization of Chironomidae (Diptera) larvae during the decomposition of Eichhornia azurea (Swartz) Kunth (Commelinales: Pontederiaceae) leaves in a lake in southeastern Brazil in two seasons of the year. The experiment was conducted from September to November 2007 and February to April 2008. In each period, 21 litter bags were used, each containing 10 g of dried leaves. Three bags were removed after 2, 5, 8, 12, 25, 45, and 65 days of colonization. The decomposition rate of the E. azurea leaves was rapid in both seasons, with no significant difference between them. The Chironomidae showed higher density than the other invertebrates. Goeldichironomus, Tonytarsus, and Corynoneura were the most abundant genera of Chironomidae. The invertebrate density increased during the experiment, differing within days but not between seasons. The faunal composition differed between the decomposition phases (initial and final), but did not differ between the seasons (dry and wet). The taxa Ablabesmyia, Caladomyia, Chironomus, Goeldichironomus, and Parachironomus were the most closely related to the final days of the experiment. Litter was the main food item found in the gut contents of the organisms of all the genera analyzed, both at the beginning and end of the decomposition. We believe that the feeding activity combined with the high larval density is an important factor contributing to the rapid decomposition of the E. azurea leaves. In conclusion, the succession process along the detritus chain of E. azurea was more important in structuring the assemblage of Chironomidae larvae than seasonal variations.

Highlights

The macrophyte Eichhornia azurea (Swartz) Kunth (Commelinales: Pontederiaceae) is widely distributed in Neotropical regions, including throughout Brazil (Barret 1978; Alves dos Santos 1999)
There was no difference in mass loss between stations (ANCOVA, F1,41 = 3.16; p = 0.08), and the decomposition rate was 0.023 d-1 in the dry season and 0.018 d-1 in the wet season
The decomposition of the E. azurea leaves was rapid in both seasons, according to the classification of Petersen and Cummins

Summary

Introduction

The macrophyte Eichhornia azurea (Swartz) Kunth (Commelinales: Pontederiaceae) is widely distributed in Neotropical regions, including throughout Brazil (Barret 1978; Alves dos Santos 1999). Aquatic plants play a fundamental role in various ecological processes, with the decomposition of their biomass being one of the main routes for cycling organic matter (Azevedo et al 2008). Macrophytes are important sources of litter (Pieczyfiska 1986), utilized as food and shelter by aquatic invertebrates (Gonçalves et al 2000). The decomposition process depends on many factors, but invertebrates are a key component of this process, playing important roles such as leaf litter fragmentation, which increases the area available for decomposing microorganism's colonization, and increasing the nutritional content of the litter by depositing their excreta on the leaf fragments (Graça 2001). The role of shredding invertebrates, especially in tropical regions, is still not very clear (Mathuriau and Chauvet 2002; Gonçalves et al 2006)

Objectives

Methods

Results

Conclusion