Invasive Biology of Apple Snails

Pomacea spp., commonly known as apple snails, are freshwater gastropods native to South America that have become globally invasive pests. Two species in particular, P. canaliculata and P. maculata, have spread via aquaculture, the pet trade and inadvertent human transport. Their high fecundity, desiccation-resistant egg masses deposited above the waterline, and generalist feeding habits enable rapid colonisation of rice paddies, wetlands and riparian habitats. These snails exert profound ecological impacts by over-grazing submerged vegetation, altering nutrient cycling and displacing native invertebrates. Economically, they cause substantial yield losses in rice and taro cultivation and can serve as vectors for zoonotic pathogens. Physiologically, apple snails possess a dual respiratory system combining a gill and an air-filled lung cavity, affording resilience to hypoxia and drought. Immune defences in kidney and lung tissues act as barriers against parasites and microbial infections, while perivitelline egg proteins confer protection against predation and digestion. Genetic studies have elucidated multiple introduction pathways and contrasting haplotype diversity among invasive populations. Predictive arrival and establishment models, based on climatic tolerance and water chemistry, guide surveillance and management. Integrated control strategies range from manual collection and biocontrol with predators to wetland modifications and regulatory measures, yet eradication remains elusive. Continued interdisciplinary research is essential to refine risk assessment, develop targeted mitigation and safeguard both natural and agricultural freshwater systems.

Research from Nature Portfolio

Recent studies have refined our understanding of the geographic origins and dispersal routes of invasive apple snails. Comprehensive phylogeographic analyses of mitochondrial DNA sequences across native and introduced ranges have demonstrated that populations of P. canaliculata in East Asia derive predominantly from Argentine lineages, indicating multiple introduction events. Conversely, invasive P. maculata populations in China trace back to a single genetic lineage, consistent with a one-time introduction. These insights resolve long-standing taxonomic ambiguities, clarify species distributions, and underpin more effective biosecurity policies to prevent further spread.

Invasive Biology of Apple Snails publication trend

The graph below shows the total number of articles in invasive biology of apple snails across all publications each year (not limited to Nature Index journals).

Technical terms

Phylogeography: Study of the historical processes shaping the geographic distribution of genetic lineages within and among species.

Mitochondrial COI gene: Mitochondrial cytochrome c oxidase subunit I region commonly used as a molecular marker for species identification and phylogenetic analysis.

Haplotype: A group of alleles at adjacent locations on a chromosome inherited together as a unit, often used to trace lineage relationships.

MaxEnt modelling: A presence-only species distribution modelling technique based on the principle of maximum entropy to predict potential habitat suitability.

Hemocyte: Circulating immune cell in molluscs involved in phagocytosis and nodulation during defence responses.

References

1. Distribution and the origin of invasive apple snails, Pomacea canaliculata and P. maculata (Gastropoda: Ampullariidae) in China. Scientific Reports (2018).
2. The identity, distribution, and impacts of non-native apple snails in the continental United States. BMC Ecology and Evolution (2007).
3. Climate and pH Predict the Potential Range of the Invasive Apple Snail (Pomacea insularum) in the Southeastern United States. PLOS ONE (2013).
4. Assessment of the kidney and lung as immune barriers and hematopoietic sites in the invasive apple snail Pomacea canaliculata. PeerJ (2018).
5. The Role of the Proteinase Inhibitor Ovorubin in Apple Snail Eggs Resembles Plant Embryo Defense against Predation. PLOS ONE (2010).
6. Cryptic diversity: Two morphologically similar species of invasive apple snail in Peninsular Malaysia. PLOS ONE (2018).
7. Functional and evolutionary perspectives on gill structures of an obligate air-breathing, aquatic snail. PeerJ (2019).
8. Biological control of golden apple snail, Pomacea canaliculata by Chinese soft-shelled turtle, Pelodiscus sinensis in the wild rice, Zizania latifolia field. Scientia Agricola (2012).