The best known of the Florida predatory snails is the rosy wolfsnail, Euglandina rosea (Férussac, 1821), which was exported to Hawaii and other areas (Mead 1961) in vain attempts to control the giant African snail, (Achatina fulica Bowdich, 1821). A Mediterranean snail, the decollate snail, Rumina decollata (Linnaeus, 1758), is much heralded today (Fisher et al. 1980) in California as an effective biological control agent of the brown garden snail, Cornu aspersum (Müller, 1774). Relatively little is known of the other three species of snail-eating snails, two of which are less than 10 mm long. All of these Florida predaceous snails are easy to identify and the following account summarizes what is known of their distributions, identification and habits.
Distribution: In the United States: Alabama, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina and southeastern Texas. It is widespread in Florida, including the Keys. It is widespread, but usually found singly in hardwood forests, roadsides and urban gardens (Hubricht 1985).
Comments: This snail was chosen as a possible biological control agent of the giant African snail. Live specimens were sent to Hawaii in 1955 (Mead 1961). Although feeding in Achatina was observed, as well as on the Asian tramp snail, Bradybaena similaris (Férussac, 1821) and native tree snails (Hart 1978), no real control was achieved. The snail reproduced rapidly in Hawaii and, by 1958, 12,000 snails were harvested for release in other Hawaiian Islands, New Guinea, Okinawa, Palau Islands, Philippines and the Bonin Islands. Chiu and Chou (1962) gave details of the biology of Euglandina in Taiwan. Individuals live up to 24 months and adults lay 25 to 35 eggs in a shallow pocket in the soil. These hatch after 30 to 40 days. In Taiwan, Euglandina consumed as many as 350 Achatina during its lifetime. Euglandina rosea is now considered invasive in Hawaii as it has caused the extinction of eight native snail species.
Distribution: Native to the Mediterranean area, but introduced widely in the United States, Bermuda and Mexico. It is widespread, but localized, in the Sun Belt from California east to Florida and north along the Atlantic coast to Pennsylvania. Very localized populations in Florida are known from Pensacola (Dundee 1970), Miami, Key Vaca and Marathon.
Comments: This snail was long considered a minor plant pest (Brantlinger 1953), although recognized as omnivorous. In California (Fisher et al. 1980), studies showed this snail is an effective predator of half-grown brown garden snails in particular and, like the brown garden snail, prospered only in cultivated habitats with frequent irrigation. It is thought that rodents limit the feral spread of the snails. Decollate snails will feed on new sprouts, old leaves, especially those in contact with the soil, and fallen bruised fruit. Their value in controlling the brown garden snail is considered to outweigh their minor pest attributes in California. These snails are ground dwellers, living among leaves, and sometimes burrowing in the upper one inch of soil (Fisher et al. 1980).
Distribution: Southern Canada to the Gulf States and west to eastern Nebraska and Oklahoma (Hubricht 1985). In Florida, it is presently known only from counties bordering the Apalachicola River.
Comments: Found in humid hardwood forests, living in leaf litter at tree bases, or under rotting logs. Pilsbry (1946) states that this family is rapacious, but Hubricht (1985) found this species feeding on dead shells more often than living snails, suggesting that this species may be using other snails as a source of lime rather than as prey. In Florida, these snails, especially juveniles, could be confused with the smaller, introduced species of Oxychilus. However, the much broader and open umbilicus of Haplotrema is distinctive.
Distribution: Introduced from Orient (Burch 1962) or southern Africa (Dundee 1974). Widespread in the Caribbean region. In the United States, apart from Florida, it is also known from Louisiana, Mississippi, South Carolina, and Texas (Dundee 1974). It is also found in Brazil, Nicaragua, Australia (Northern Territory), and the Pacific area.
Comments: This snail is apparently an effective predator of Subulina octona (Bruguière, 1798) (Mead 1961) and pupillids (Dundee and Baerwald 1984). In Florida, the presence of four apertural teeth is diagnostic except for some tiny species of Pupillidae which are distinguished by their ovate or pupate shapes.
Distribution: Collected only from the Florida Keys and the Miami area. The subspecies Varicella g. gracillima (Pfeiffer 1851) occurs in Western Cuba (Pilsbry 1946).
Comments: These snails live under leaf litter, logs and rocks, usually in hardwood hammocks. No studies have been made of their biology, but Burch (1962) implied they are predatory on other snails.
Authors: Kurt Auffenberg and Lionel A. Stange, Florida Department of Agriculture and Consumer Services, Division of Plant Industry; T.R. Fasulo, University of Florida
Originally published as DPI Entomology Circular 285. Updated for this publication.
Photographs:Paul M. Choate, Lyle J. Buss and John Slapcinsky, University of Florida; Bill Frank, www.jaxshells.org;
Drawing: FDACS-Division of Plant Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-251
Publication Date: November 2001. Latest revision: July 2011.
Copyright 2001-2011 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
E. rosea
E. rosea top view
E. rosea reverse view
R. decollata top view
R. decollata reverse view
H. concavum
H. concavum
H. bicolor
V. gracillima floridana