[Natural microbial control of crickets populations (Orthoptera: Gryllotalpidae: Scapteriscus borellii): regulation of populations aggregated in time and space].

From 1983 through 1988, a total of 1,762 collections, containing 31,312 individuals of the mole cricket, Scapteriscus borellii, were made, principally in the State of São Paulo, Brazil. Collections were found to fit a negative binomial distribution both as whole and when divided into monthly collections. In these collections, an iridovirus, a entomogenous nematode, and the fungi Metarhizium anisopliae, Beauveria bassiana, Paecilomyces sp., and Entomophtora sp., were found to be agents of natural mortality, although usually as endozootics and relatively rarely as epizootics and panzootics. As a group, these diseases were also distributed in a binomial negative. These data suggest that the temporal and spatial aggregations of the mole crickets, produced by high rates of migration among suitable habitats, are adaptations to outbreaks of epidemics, which also serve as mole cricket population regulators. These ideas are develop and derived from simple mathematical models of population change.