Distribution and Turnover Rate of a Population of Atta cephalotes in a Tropical Rain Forest in Costa Rica

A population of Atta cephalotes was surveyed in 1989 and 1991 at the La Selva Biological Station in Costa Rica. Nests were mapped along trails that passed through old growth forest. Estimates of basic demographic parameters were examined in relationship to general soil categories, suggesting that colony mortality and natality is related to soil type. Results indicated that the population is increasing at a rate of 22 percent per annum. Based on initial nest size data and on demographic parameters, a complete forest soil turnover time of 200 to 300 yr was estimated. The significance of these results for plant community dynamics are discussed.