DISTRIBUTIONAL PATTERNS OF SPECIES, INDIVIDUALS AND BIOMASS IN NATURAL COMMUNITIES

Abstract

The main goal of this essay is to examine whether, despite the great number of insect species and the enormous number of individuals in a community, we may observe any kind of regularities or if there are internal constraints that could be placed on models of distributional pattern. More than 25.000 individual insects distributed in 1,000 species of the Orders Coleoptera. Homoptera, Heteroptera and Lepidoptera were collated in a tropical region (Restinga de Marica, State of Rio de Janeiro). Six community variables were examined: 1) number of species, 2) number of individuals, 3) body size. 4) species diversity. 5) ecological succession, and 6) turnover rate of biomass. The results from this analysis were compared to data from other, both tropical and temperate communities. Two results are most important: 1) the distribution of biomass in body size classes varies gradually through the year (seasonally), and 2) The number of species and individuals in the small body size classes is strongy environment (temperature) controlled. The pattern of these data on the body size characteristic from Marica has the merit of reconciling, series of apparent discrepancies in recently published results from other systems.

Starting from the concept of ecological succession, the idea of a general tendency of natural systems to reduce the rate of biomass turnover is advanced. We term this the Macunaima tendency.