The aquatic macrofauna of water-filled bamboo (Poaceae: Bambusoideae: Guadua) internodes in a Peruvian lowland tropical forest
Biotropica
1996
Journal Article
28
2
228-242
aquatic insects bamboo community ecology helicopter damselfly mosquitos phytotelmata tree-holes ecology food Pakitza inventories predation abundance invertebrates Parque Nacional del Manu Guadua Poaceae Bambusoideae aquatic habitats small spatial scales Madre de Dios Bibliography
In the lowland tropical forest at Pakitza, Peru, bamboo (Guadua weberbaueri Pilger) internodes with lateral perforations contain a diverse aquatic fauna. We found a community of 29 species dominated by Diptera, primarily mosquitos, and an undescribed helicopter damselfly (Mecistogaster). Although most studies of bamboo concern broken or cut culms filled with rainwater, the water in the live bamboo internodes that we studied was supplied by plant secretions. This results in an aquatic habitat that persists even during the pronounced local dry season. The lateral openings typically consist of closely-spaced rows of parallel slots and are possibly formed by the activities of ovipositing female katydids (Leiobliastes laevis Beier) and secondarily enlarged by various means. Succession in this community was found to follow the steps in development of the lateral opening; with increases in the average number of species and individuals, and percent of the total fauna present, as the opening size increased. We explored patterns of community structure by descriptive statistical analyses and constructed a tentative food web diagram of this simple aquatic ecosystem. Pairwise comparisons of ranked abundances of aquatic insects failed co show correlation, but internodes that contained a predator had higher average simple diversity of mosquito species than chose without, indicating a possible ''Paine effect.'' While species counts and counts of total individuals were not significantly correlated with type of lateral perforation, counts of individuals of all taxa per internode were correlated with size of lateral perforation. Number of mosquito species was signifcantly correlated with volume of water held in the internodes.