Reproductive Ecology of the Freshwater Snail, Pila globosa, Considering Environmental Factors in a Tropical Freshwater Swamp Forest

Abstract

The apple snail Pila globosa is a widely distributed mollusc in tropical freshwater ecosystems, where it plays a crucial ecological role. This study examined the morphometric features, condition indices, and reproductive traits of P. globosa to gain insights into its population structure in the Ratargul Freshwater Swamp Forest, Bangladesh. Water quality parameters were recorded, and various morphometric measurements were analysed, including their correlations and seasonal variations. The mean values for shell length, shell weight, shell width, spiral length, base length, aperture length, aperture width, and soft tissue wet weight were 4.64 ± 0.97 cm, 38.29 ± 15.27 g, 3.56 ± 0.74 cm, 2.32 ± 0.51 cm, 3.33 ± 0.74 cm, 3.46 ± 0.64 cm, 2.01 ± 0.45 cm, and 18.05 ± 11.39 g, respectively. Linear regression analyses revealed strong correlations among length–length and length–weight parameters, indicating consistent growth patterns. Monthly frequency distributions showed distinct variations in shell size and form. The sex ratio was 1:1.23 (male–female), not significantly different from parity. Histological analysis during the rainy season revealed reproductive activity, including mature ova, previtellogenic and vitellogenic oocytes, and spermatogonia and spermatids. These findings enhance understanding of the species’ biology and its interaction with environmental conditions, offering valuable data for the conservation and management of freshwater mollusc populations in wetland ecosystems.