Succession of the richness, abundance and species composition of frugivorous insects in Psidium guajava (L.)

Abstract

The maintenance of species diversity is a comple xphenomenon whose determinant factors can act in many spatial scales from local habitats to the regional level. We analyzed the habitat use by frugivorous insects in three categories of Psidium guajava fruits. We found 2,140 individuals of 22 morphospecies, of which Diptera (6 spp.), Hymenoptera (6 spp.), and Coleoptera (5 spp.) were the richest orders. Diptera was the most abundant order, with 93% of the total collected individuals (1,986 ind.). The greatest richness occurred in the fruits on the litter: 19 spp., contrasting with 7 spp. in ripe fruits and 2 spp. in unripe fruits on the tree. Diversity was significantly higher in fruits on the litter. Similarity was greatest between unripe and ripe fruits on the tree (0. 50). Abundance (r2 = 0.08; r = 0.29, p = 0.00) show a positive and significant relation with total volume of the all fruit categories Abundance (Log10) in unripe fruits correlated positive and significantly with total diameter of these fruits (r2 = 0.12; r = 0.35, p = 0.04). Variations in invertebrate richness, abundance, diversity, and density in the three fruit categories suggest different community establishment restriction levels. The physical and biological change gradients in the P. guajava fruits represent a heterotrophic succession. The temporal and spatial position of the fruits promotes variations in their physical and chemical properties. This variation in resource quality creates microhabitat heterogeneity and makes the presence and co-existence of many species of frugivorous invertebrates possible.Key words: diversity, microhabitat heterogeneity, heterotrophic succession, Psidium guajava