''Euglandina rosea'', the rosy wolfsnail or cannibal snail, is a species of medium-sized to large predatory air-breathing land snail, a carnivorous terrestrial

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family Spiraxidae.MolluscaBase eds. (2020). MolluscaBase. Euglandina rosea (Férussac, 1821). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1289331 on 2020-11-09 This species is a fast and voracious predator, hunting and eating other snails and slugs.Clifford, Kavan T., Liaini Gross, Kwame Johnson, Khalil J. Martin, Nagma Shaheen, and Melissa A. Harrington. (2003)."Slime-trail Tracking in the Predatory Snail, Euglandina Rosea." Behavioral Neuroscience 117.5:1086-095. The rosy wolfsnail was introduced into

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

in 1955 as a biological control for the invasive African land snail, '' Lissachatina fulica''.Gerlach, Justin. (1994). “THE ECOLOGY OF THE CARNIVOROUS SNAIL EUGLANDINA ROSEA.” Diss. Wadham College, Oxford. This snail is responsible for the

extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

of an estimated eight native snail species in Hawaii.Kurt Auffenberg & Lionel A. Stange (November 2001). "Snail-eating snails of Florida, Gastropoda". University of Florida. EENY251. Retrieved October 7, 2012. This has caused the snail to be added to the IUCN's top 100 most invasive species.

Description

The rosy wolfsnail lives around 24 months. The snail takes 30–40 days to hatch and is then considered young (before sexual maturity). Sexual maturity begins between 4 and 16 months after hatching. The snail is relatively fast moving at about 8 mm/s. The snail has a light grey or brown body, with its lower tentacles being long and almost touching the ground. The shell has usual dimensions of 76 mm long and 27.5 mm in diameter. The shape of the shell tapers to a point at both ends (

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

) with a narrow oval- to crescent-shaped opening and a shortened axis of the spiral shell near the opening (truncated columella). The shell has a brownish pink color. The full-grown adult snail ranges in size from 7–10 cm in length.

Ecology

This species is found naturally in the Southern United States, usually in hardwood forests and urban gardens.Hubricht L. (1985). "Distributions of the native land mollusks of the eastern United States". Fieldiana: Zoology (new series) No. 24: i-viii, 1-191. It is a fast and voracious predator, hunting and eating other snails and slugs. The smaller prey species are ingested whole or sucked out of their shells. This gives it the nickname "the cannibal snail". Rosy wolfsnails use slime trails to track their prey and potential mates, resulting in rosy wolfsnails following these trails more than 80% of the time they are alive. The rosy wolfsnail prefers to consume smaller snails because these are quicker and easier to eat.Cook, Anthony. (1989). "Factors Affecting Prey Choice And Feeding Technique In The Carnivorous Snail Euglandina Rosea Ferussac." Journal of Molluscan Studies 55.4: 469-77. Euglandina rosea drawing

The rosy wolfsnail is specialized for carnivory, its buccal mass being totally contained within a beak-like

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

that can be extended, thus allowing the toothed

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

to be ejected past the mouth and into the snail's prey. The radula is enlarged and has teeth specialized into elongated cones. The four main mammalian predators for the rosy wolfsnail are rats,

tenrec A tenrec () is a mammal belonging to any species within the afrotherian family Tenrecidae, which is endemic to Madagascar. Tenrecs are a very diverse group, as a result of adaptive radiation, and exhibit convergent evolution, some resemble hed ...

s, pigs, and

mongoose A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family has two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to southern Europe, A ...

s. The rats consume the snail by chewing the top of the shell off. The tenrecs crack the shell into large pieces. The pigs have a tendency to crush the shell completely. The mongooses attack the body of the snail. Cannibalism among adults has also been seen in the rosy wolfsnail. However, this has only been observed in captive populations and appears to be a rare occurrence. Diseases affect the survival of the rosy wolfsnail, as well. One disease known to affect the snail is caused by the pseudomonad bacterium ''

Aeromonas hydrophila ''Aeromonas hydrophila'' is a heterotrophic, Gram-negative, rod-shaped bacterium mainly found in areas with a warm climate. This bacterium can be found in fresh or brackish water. It can survive in aerobic and anaerobic environments, and can ...

''. Infection occurs by ingesting the bacteria, if they contaminate the snail's food, or by contact with another individual that is infected. This causes reduced digestive function, resulting in emaciation even when food is abundant. This finally results in a slow death by starvation. The rosy wolf snail is a

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

and is

oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

. The courtship rituals for the snail begin with one following the trail of another snail. The pursuing snail then mounts the rear side of the shell of the snail it was following. Following this mounting, a head-waving display ensues, where the pursuing snail vigorously shakes its head for 15 minutes. This ultimately ends with a short period of inactivity, where the mounted snail turns its head to face its own shell. Following this,

copulation Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for sexual pleasure, reproduction, or both.Sexual inte ...

occurs, with the one snail still mounted on the shell of the other, the two heads are brought together, and then twisted around each other's necks, enabling genital contact. This copulation then lasts up to four hours. An adult snail lays 25–35 eggs in a shallow pocket of soil and the eggs hatch after 30–40 days. The snail has been known to go into

hibernation Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is mos ...

during winter and emerge in April/May.

Distribution and habitat

The rosy wolfsnail is native to the Southeastern United States, including Florida and Georgia. Other species of the genus are native to South and Central America.

As an invasive species

The rosy wolfsnail has become an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

in many areas outside its native range, including in Hawaii. These predatory snails were originally introduced to Hawaii in an attempt to eliminate another invasive species, the giant African land snail, '' Lissachatina fulica''. The introduction occurred in 1955, when specimens were collected from Florida and sent to Hawaii. During the same year, 616 individuals were released on Oahu. In 1958 12,000 were taken from Oahu and introduced onto eight other Pacific islands. This did not, however, reduce the populations of ''A. fulica'', but rather caused a decline in native snail populations. The

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

vigorously attacked the endemic O'ahu tree snail. As a result, many tree snail species were hunted to extinction within the first year. These predatory snails continue to represent a threat to the local snail fauna.Claire Régnier, Benoît Fontaine & Philippe Bouchet (2009). "Not knowing, not recording, not listing: numerous unnoticed mollusk extinctions". Conservation Biology. 23 (5): 1214–1221. doi:10.1111/j.1523-1739.2009.01245.x. PMID 19459894. Of all known mollusk extinctions since 1500, about 70% are from islands, and an estimated one-third of these were caused by introduced ''E. rosea''. These prey snails were at an increased risk of predation-caused extinction because of their extremely low reproduction rates. The rosy wolfsnail has caused the extinction of an estimated eight native snail species in Hawaii. Due to this, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

(IUCN) has placed the rosy wolfsnail on the list of the top 100 worst invasive alien species in the world.

Control strategies

One strategy to protect native snails from the predatory rosy wolfsnail has been to breed the native tree snails in captivity, then introduce the small population into a predator-proof patch of forest. This forest patch consists of a galvanized iron barrier; at the base of the iron barrier, a plastic trough was attached and filled with salt and then a pair of electric wires connected to a battery. This created a protected enclosure with both chemical and electrical defenses. The enclosure allows the native snails to breed in a safe location, but does not allow them to travel outside of the protected area. Other forms of control for the rosy wolfsnail have been investigated. The three main methods of control being used or discussed are collection and chemical and biological control. The use of collection has not been extensively used because it is too labor-intensive and time-consuming. Chemical poisoning has been used extensively in many areas, though it is not very effective in controlling the ''E. rosea'' population.

Biological control Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or o ...

has been a favored option.

Policy and laws

The rosy wolfsnail is now legally considered to be a "noxious species in French Polynesia". This means that live individuals cannot be brought to the islands.Meyer, Jean-Yves. (1998)."Observations on the Reproductive Biology of Miconia Calvescens DC (Melastomataceae), an Alien Invasive Tree on the Island of Tahiti (South Pacific Ocean)1." Biotropica 30.4: 609-24. The IUCN states that the introduction of the rosy wolfsnail to non-native habitats is now formally discouraged.

References

External links

*
Featured Creatures website': ''Euglandina rosea''
— University of Florida, Institute of Food and Agricultural Sciences—IFAS''.

* ttp://islandbiodiversity.com/euglandina.htm Euglandina and Partula - biology and news {{Authority control Spiraxidae Molluscs of North America Fauna of the Southeastern United States Gastropods described in 1821