Life Table and Demographic Parameters of the Neotropical Apple Snail Asolene platae (Caenogastropoda, Ampullariidae)

Abstract

Apple snails are regarded as invasive or potentially problematic species but some species may be under threat. Life tables are a useful tool to understand the growth potential of freshwater snail populations. Our aim was to estimate the demographic parameters of the Neotropical apple snail Asolene platae (Maton, 1811) to allow a quantitative comparison with invasive apple snails like Pomacea canaliculata (Lamarck, 1822). Life tables were calculated for three laboratory cohorts bred at 25 °C. Life expectancy rises abruptly up to 32-37 months after a period of high post-hatching mortality of one month. The reproductive value peaked at 15-19 months for two cohorts and at 33 months in the other one. The net reproductive rates (R0), generation times (GT) and intrinsic rates of increase (r) were as 55.86 hatchlings, 25.7 months, and 0.188 individuals per individual per month on average, respectively. Among freshwater snails there is a clear inverse relationship between r and GT while R0 has a minor positive influence. The values of GT and r for A. platae are among the highest and lowest, respectively, calculated for freshwater snails at 24-26 °C. These low values of r under optimum conditions indicate a relatively low potential of A. platae populations to increase in new habitats or to recover from disturbances.