Apple Snail

This is a large freshwater gastropod mollusk characterized by a globose, heavy shell with deeply channeled sutures separating the whorls. Shell coloration is highly variable, ranging from bright yellow and golden shades to greenish-brown, frequently adorned with dark spiral bands. Adult specimens commonly measure between 1.5 and 3 inches (approx. 40 to 75 millimeters) in shell height, with exceptional individuals exceeding 4.7 inches (120 millimeters). It possesses a concentric, horny operculum that provides a tight seal. Its anatomical highlights include a remarkably long, contractile respiratory siphon and a dual breathing system utilizing both gills and a functional lung.

Geographical distribution: This species is native to the temperate and tropical regions of South America, specifically throughout the Amazon River and Río de la Plata basins, spanning Argentina, Brazil, Paraguay, Uruguay, and Bolivia. However, through accidental releases and intentional introductions for aquaculture, it has successfully invaded Southeast Asia, the southern United States (including Florida and Texas), parts of Europe, and several Pacific islands, where it is recognized as a major pest.

Habitat: It colonizes a vast range of lentic and slow-moving freshwater ecosystems, including swamps, marshes, shallow lakes, irrigation ditches, and flooded rice paddies. The species exhibits an extraordinary tolerance to low dissolved oxygen levels and fluctuating temperatures. During dry spells, it survives by burying itself into the moist substrate, undergoing aestivation for several months until wet conditions return.

Feeding: It functions as a highly voracious, generalist herbivore that primarily consumes macrophytes, algae, and organic detritus. Equipped with a strong, abrasive radula, it easily grinds down aquatic vegetation, which can lead to the complete devastation of aquatic plant communities in non-native habitats, altering nutrient cycling and destabilizing local ecosystems.

Behavior: It exhibits predominantly crepuscular and nocturnal activity patterns, resting submerged or buried during the day to avoid predators. Its amphibious nature allows it to breathe atmospheric oxygen by extending its siphon above the water line while remaining submerged. When threatened, it rapidly retracts its soft body into the shell, sealing the aperture securely with its operculum.

Reproduction: This is a dioecious species with separate sexes and internal fertilization. After mating in the water, the female crawls out of the aquatic medium at night to deposit her eggs. The egg clutches are distinctive, consisting of bright pink to coral-red clusters containing 200 to 600 eggs, which are cemented to emergent vegetation, rocks, or concrete walls to protect them from aquatic predators. Incubation lasts approximately 10 to 15 days, after which the hatchlings drop directly into the water.

Conservation status: Within its native South American range, the species is widespread and classified as Least Concern (LC). Conversely, from a global perspective, it is listed among the 100 of the world´s worst invasive alien species by the IUCN, posing severe threats to agricultural economies and native freshwater biodiversity.