Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Non-native apple snails: systematics, distribution, invasion history and reasons for introduction.


The freshwater snail family Ampullariidae includes nine extant genera. Species of Pomacea in particular, but also species of Pila and Marisa, have become invasive where they have been introduced. Introduction of Pomacea spp. to Asia around 1980, initially to Taiwan, followed by their rapid range expansion and development as serious agricultural pests, especially of wetland rice, led to a dramatic increase in research not only in the means to control them but also in the basic systematics necessary to identify them. Ampullariid systematics has always been confused but the advent of molecular approaches, combined with modern morphological study, including extensive study of type material, determined that the two key invasive species in Asia, as well as in the USA and elsewhere, are Pomacea canaliculata and Pomacea maculata. Additional introduced species, both in Asia and elsewhere, include Pomacea scalaris (Taiwan), Pomacea diffusa (Sri Lanka, Australia, USA) and Marisa cornuarietis (Caribbean islands, Spain, USA). Pila scutata may have been transported widely in Asia but its native or introduced status in many Asian countries is not clear; however, it has been introduced to and is established in Hawaii. The main reasons for introduction of these species have included introduction as a human food resource, as a domestic aquarium snail, for biocontrol of other snails that act as vectors of the parasites causing schistosomiasis, and for control of aquatic weeds.