Zachrysia provisoria (Cuban brown snail)

Pictures

Picture	Title	Caption	Copyright
Title Adult Caption Zachrysia provisoria (Cuban brown snail); adult. Copyright ©Lyle J. Buss/University of Florida-2010	Adult	Zachrysia provisoria (Cuban brown snail); adult.	©Lyle J. Buss/University of Florida-2010
Title Adult Caption Zachrysia provisoria (Cuban brown snail); adult. Copyright ©Lyle J. Buss/University of Florida-2010	Adult	Zachrysia provisoria (Cuban brown snail); adult.	©Lyle J. Buss/University of Florida-2010
Title Adult Caption Zachrysia provisoria (Cuban brown snail); adult. Note coin for scale. Copyright ©Lyle J. Buss/University of Florida-2010	Adult	Zachrysia provisoria (Cuban brown snail); adult. Note coin for scale.	©Lyle J. Buss/University of Florida-2010
Title Adult Caption Zachrysia provisoria (Cuban brown snail); adult. Note mm scale. Copyright ©Lyle J. Buss/University of Florida-2010	Adult	Zachrysia provisoria (Cuban brown snail); adult. Note mm scale.	©Lyle J. Buss/University of Florida-2010
Title Egg cluster in soil Caption Zachrysia provisoria (Cuban brown snail); egg cluster in soil. Adults burrow several cm deep in loose soil to deposit the eggs. Copyright ©Lyle J. Buss/University of Florida-2011	Egg cluster in soil	Zachrysia provisoria (Cuban brown snail); egg cluster in soil. Adults burrow several cm deep in loose soil to deposit the eggs.	©Lyle J. Buss/University of Florida-2011
Title Egg cluster, post hatching. Caption Zachrysia provisoria (Cuban brown snail); egg cluster, most post hatching. Copyright ©Lyle J. Buss/University of Florida-2010	Egg cluster, post hatching.	Zachrysia provisoria (Cuban brown snail); egg cluster, most post hatching.	©Lyle J. Buss/University of Florida-2010
Title Hatchling Caption Zachrysia provisoria (Cuban brown snail); hatchling. Note scale. Copyright ©Lyle J. Buss/University of Florida-2010	Hatchling	Zachrysia provisoria (Cuban brown snail); hatchling. Note scale.	©Lyle J. Buss/University of Florida-2010
Title Adult, showing epiphragm Caption Zachrysia provisoria (Cuban brown snail); adult, showing epiphragm lifted (a) and closed (b). This structure is produced to retard desiccation and is only present under dry conditions. Copyright ©Lyle J. Buss/University of Florida-2010	Adult, showing epiphragm	Zachrysia provisoria (Cuban brown snail); adult, showing epiphragm lifted (a) and closed (b). This structure is produced to retard desiccation and is only present under dry conditions.	©Lyle J. Buss/University of Florida-2010

Identity

Preferred Scientific Name

• Zachrysia provisoria Pfeiffer, 1858

Preferred Common Name

• Cuban brown snail

Summary of Invasiveness

Z. provisoria is a terrestrial snail, native to Cuba, that has expanded its range to many of the Caribbean Islands. Although long established in the Bahamas and USA (Florida), in the early 2000s it was detected on several islands in the Lesser Antilles, Jamaica and the Cayman Islands. Z. provisoria is a generalist, feeding on many different plants. It is mostly regarded as a pest of horticultural plants rather than food crop plants. It hitch-hikes readily, and is often detected in horticultural shipments originating from Florida. It has also been detected in shipments from Guatemala, Costa Rica, Haiti and the Dominican Republic, where it is not known to be established (Robinson and Fields, 2004). Thus, its range may be greater than generally acknowledged. An assessment of its invasiveness ranked it an intermediate threat among potential mollusc invaders (Cowie et al., 2009).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Mollusca
•             Class: Gastropoda
•                 Subclass: Pulmonata
•                     Order: Stylommatophora
•                         Suborder: Sigmurethra
•                             Superfamily: Helicoidea
•                                 Family: Camaenidae
•                                     Genus: Zachrysia
•                                         Species: Zachrysia provisoria

Notes on Taxonomy and Nomenclature

The gastropod genus Zachrysia is in the superfamily Helicoidea which is a large and diverse group of land snails. Its family assignment to the Camaenidae is under review because molecular studies support the separation of the Australasian Camaenidae sensu stricto from the the species that, like Zachrysia, originate from the Americas (Bouchet and Rocroi, 2005; Wade et al., 2007). Z. provisoria was originally described as Helix provisoria. It greatly resembles Z. auricoma (Férussac) and Z. trinitaria (Gundlach in Pfeiffer, 1858), so many reports in the literature are suspect.

Description

Z. provisoria is a globose, medium-sized snail, typically measuring 25 to 30 mm in diameter at maturity. The shell consists of 4-5 rapidly expanding whorls. It lacks an umbilicus (a hollow cone-shaped space found within the whorls of a coiled mollusc shell, visible from below). Regular, strong, curved ribs are found on the upper surface of the shell, though the lower surface is less well sculptured. The margin (lip) of the aperture (opening) and columella is typically white, in sharp contrast with the brown (yellowish-brown to dark brown) shell. The aperture margin may be slightly thickened and expanded (flared), but not markedly. There is only a slight expansion of the columella wall basally rather than a sharp tooth (Auffenberg and Stange, 1993).

Distribution

This species is native to Cuba and probably reached the Bahamas late in the 19th century (Pilsbry 1928; Diesler and Abbott, 1984). It has since been detected on a variety of Caribbean islands. It has also been detected in shipments from Guatemala, Costa Rica, Haiti and the Dominican Republic, where it is not known to be established (Robinson and Fields, 2004). Thus, its range may be greater than generally acknowledged.

Based on a report by Clapp (1919), Z. provisoria is assumed to have been established in Florida for many years. Presently, Z. provisoria is regularly intercepted in horticultural shipments from Florida. Most of the current geographic range inhabited by Z. provisoria has been attained only recently.

Its status in Central America is uncertain. There is an unconfirmed report of it occurring in India (Pandey and Dhar, 2013), which would be it first occurrence outside the Western Hemisphere.

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Introductions

Risk of Introduction

Z. provisoira has considerable potential for spread to other tropical and sub-tropical locations. It will burrow into soil, so often escapes detection in potted plants. Ornamental plants produced in Florida are regularly shipped to other states in the coastal regions of southern USA and to California, where this species could likely establish. Similarly, its introduction to some Caribbean islands is attributed to horticultural plants shipped from Florida.

It has also been detected in shipments from Guatemala, Costa Rica, Haiti and the Dominican Republic, where it is not known to be established (Robinson and Fields, 2004).

Habitat

Pilsbry (1928) reported that Zachrysia spp. generally inhabit humid forests of Cuba, though displaying no particular habitat preference. 

Habitat List

Biology and Ecology

Reproductive biology

In Florida, Z. provisoria deposits eggs during the warm and humid summer. Snails burrow into the soil under cool and dry conditions in autumn and early spring, emerging in the late spring with the onset of rainy weather to complete their development and/or mate and deposit eggs for a new generation. So far as is known, there is one generation per year. Eggs are deposited in the soil, in loose clusters of 8-20. The hard, calcareous eggs are white, oval, 5-6 mm long and 4-5 mm wide.

Nutrition

Z. provisoria eats a large number of plants, but prefers some over others. Diet strongly affects growth rate. Many weeds seem to be suitable for growth of snails, including wild poinsettia, Poinsetia heterophylla (Euphorbiaceae); common ragweed, Ambrosia artemisiifolia (Asteraceae); Asiatic hawksbeard, Youngia japonica (Asteraceae), and Florida beggarweed, Desmodium tortuosum (Fabaceae) (Capinera, 2012). However, Z. provisoria is mainly known as a pest of ornamental crops.

Activity patterns

Zachrysia spp. are active whenever conditions are suitably humid, and inactive when it is dry.

Climate

Notes on Natural Enemies

The only known natural enemies are vertebrates, particularly birds and rats.

Means of Movement and Dispersal

Z. provisoira burrows into soil, so can be accidentally transported via the trade in potted plants and horticultural crops. It hitch-hikes readily, and is often detected in horticultural shipments.

Pathway Causes

Pathway Vectors

Economic Impact

Presently Z. provisoria is mostly an occasional pest, though its nocturnal feeding means that some damage it causes may overlooked or misattributed. Some ornamental plant growers in southern Florida estimate that they would lose 25% of their crops were they not applying molluscides regularly (Robinson and Fields, 2004). In Barbados Z. provisoria is reported to be a more important pest than the giant African snail, Lissachatina fulica (Ciomperlik et al., 2013).

Z. provisoria is known mostly as a pest of ornamental crops, affecting plants such as bougainvillea, crepe myrtle, hibiscus, ti plant, impatiens, orchids, bromeliads, ornamental asparagus, begonia, ornamental cactus, aroids (Araceae) and cut flowers. Also affected are citrus crops, brassica crops, peppers, sweet potato, starfruit, mango and others. Z. provisoria climbs trees readily and can damage tree foliage and remove bark from stem tissue (Robinson and Fields, 2004).

Social Impact

Z. provisoria is a host of rat lungworm (Angiostrongylus cantonensis), which can infect humans, so it presents some potential health risks.

Risk and Impact Factors

Impact mechanisms

• Herbivory/grazing/browsing
• Interaction with other invasive species
• Pest and disease transmission

Impact outcomes

• Altered trophic level
• Damages animal/plant products
• Host damage
• Negatively impacts agriculture
• Negatively impacts animal health
• Negatively impacts human health
• Negatively impacts trade/international relations

Invasiveness

• Benefits from human association (i.e. it is a human commensal)
• Capable of securing and ingesting a wide range of food
• Gregarious
• Highly mobile locally
• Proved invasive outside its native range
• Tolerant of shade

Likelihood of entry/control

• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field
• Difficult/costly to control
• Highly likely to be transported internationally accidentally

Detection and Inspection

Zachrysia snails are easily spread via transported potted plants, as the snails can burrow into soil during the day, thereby escaping detection.

Because Z. provisoria generally feeds at night, damage caused by it can be overlooked or misattributed. Thus, examination of plants in the evening, especially after rainfall, in advised. These snails can be quite large, and will rest above-ground, so they are easier to detect than some molluscs.

Similarities to Other Species/Conditions

Outside of its native Cuba, Z. provisoria could be confused with Z. trinitaria (Pfeiffer, 1858) and Z. auricoma havanensis (Pilsbry, 1928). At maturity, Z. trinitaria is easily distinguished by its larger size (up to 45 mm) and finer ridges on the upper surface.

Z. auricoma overlaps Z. provisoria in size, and requires dissection to differentiate these species. However, Z. auricoma, unlike other Zachrysia spp., inhabits much more open, xeric environments, probably because it has an exceptionally hard, calcareous epiphragm, with which it seals its shell.

Prevention and Control

Snails generally seek shelter from sunlight, so can be found in dense vegetation. Removal of unnecessary vegetation is a useful cultural management method. Also, because they favour high humidity, reduction in irrigation is advised. Sanitation, particularly the removal of debris or objects that can provide shelter for snails, is advised. Movement of snails onto benches, pots, tree trunks and similar sites can be reduced by ringing the site with copper metal. Similarly, copper-based fungicides such as copper hydroxide repel snails.

Snails generally are controlled using chemical toxicants that are incorporated into bait. The most common and generally most effective toxicant is metaldehyde. It works both by ingestion and by contact. Addition of carbamates to the metadehyde may provide additional toxicity, but rarely of an appreciable benefit. Metaldehyde is quite toxic to pets and wildlife.

In more recent times, iron-based toxicants have begun to replace metaldehyde as the active ingredient in toxic baits. Iron phosphate has been thoroughly studied and is quite effective, though perhaps less so than metaldehyde. The other iron-based toxicant, sodium ferric EDTA, is less well known, but generally comparable to iron phosphate in efficacy. These two toxicants must be ingested to be effective. From the perspective of causing snail mortality, the iron-based products act more slowly that metaldehyde products. However, snails cease feeding soon after ingesting the iron-based products, so damage is minimized despite the lingering survival of the snails (Capinera, 2012). The iron-based products are reported to be less of a threat to pests and wildlife.

Routine treatment of production areas with toxicants will greatly reduce the likelihood of plant infestation by Z. provisoria, as well as inadvertent transport via plants.

Gaps in Knowledge/Research Needs

Biological suppression of Z. provisoria is poorly developed. Natural enemies and pathogens of snails are poorly known.

References

Auffenberg K, Stange LA, 1993. The Camaenidae (Mollusca: Pulmonata) of Florida. Entomology Circular (Gainesville), No. 356. 2 pp.

Auffenberg K, Stange LA, Capinera JL, White J, 2011. Pleurodontid snails of Florida, Caracolos marginella (Gmelin) Zachrysia provisoria (L. Pfeiffer), Zachrysia trinitaria (L. Pfeiffer), (Gastropoda: Pleurodotidae). Featured Creatures, EENY 118. http://entnemdept.ifas.ufl.edu/creatures/misc/pleurodontidae_snails.htm

Bertrand A, 2001. Notes on terrestrial molluscs of Saint Martin (Lesser Antilles). (Notes sur les mollusques terrestres de Saint-Martin (Petites Antilles).) Documents Malacologiques, 2:35-37.

Bouchet P, Rocroi JP, 2005. Classification and nomenclator of gastropod families. Malacologia, 47(1/2):397 pp.

Capinera JL, 2013. Cuban brown snail, Zachrysia provisoria (Gastropoda): damage potential and control. Crop Protection, 52:57-63. http://www.sciencedirect.com/science/journal/02612194

Ciomperlik MA, Robinson DG, Gibbs IH, Fields A, Stevens T, Taylor BM, 2013. Mortality to the giant African snail, Lissachatina fulica (Gastropoda: Achatinidae), and non-target snails using select molluscicides. Florida Entomologist, 96(2):370-379. http://www.fcla.edu/FlaEnt/

Clapp GH, 1919. Cuban mollusks colonized in Florida. The Nautilus, 32:104-105.

Cowie RH, Dillon RT, Robinson DG, Smith JW, 2009. Alien non-marine snails and slugs of priority quarantine importance in the United States: a preliminary risk assessment. American Malacological Bulletin, 27:113-132.

Deisler JE, Abbott RT, 1984. Range extensions of some introduced land mollusks in the Bahama Islands, with first reports for four species. The Nautilus, 98:12-17.

Maceira D, Miquel SE, Espinosa J, Virgillito M, Lauranzón B, 2013. Exotic land molluscs and first date of punctidae family (Mollusca: Gastropoda Pulmonata) and the species Paraloma servilis in Cuba. (Moluscos terrestres exóticos y primera cita de la familia punctidae (Mollusca: Pulmonata Gastropoda) y de su especie Paraloma servilis para Cuba.) Solenodon, 11:95-102.

Pandey RK, Dhar A, 2013. Snail infestation on mulberry (Morus alba) in high water table area of Kathua (Jammu and Kashmir) during monsoon season. The Silkworm, 24 October. http://silkwormmori.blogspot.com/2013/10/snail-infestation-on-mulberry-morus.html

Pilsbry HA, 1928. Studies on West Indian mollusks: The genus Zachrysia. Proceedings of the Academy of Natural Sciences of Philadelphia, 80:581-606.

Robinson DG, Fields HA, 2004. Program and Abstracts of the 70th Annual Meeting of the American Malacological Society, Sanibel Island, Florida, 30 July-4 August 2004, Bailey-Matthews Shell Museum, Sanibel, Florida, 73. DOI: 10.13140/2.1296 [ed. by Leal, \J. H.].

Rosenberg G, Muratov IV, 2005. Status report on the terrestrial Mollusca of Jamaica. Proceedings of the Academy of Natural Sciences of Philadelphia, 155:117-161.

Stange LA, 2006. Snails and slugs of regulatory significance to Florida. http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Pest-Alerts/Pest-Alerts-Snails-Slugs-Of-Regulatory-Significance-To-Florida

Wade CM, Hudelot C, Davison A, Naggs F, Mordan PB, 2007. Molecular phylogeny of the helicoid land snails (Pulmonata: Stylommatophora: Helicoidea), with special emphasis on the Camaenidae. Journal of Molluscan Studies, 73:411-415.

Principal Source

Draft datasheet under review

Contributors

13/04/15 Original text by:

John Capinera, University of Florida, USA

Distribution Maps

• = Present, no further details
• = Evidence of pathogen
• = Widespread
• = Last reported
• = Localised
• = Presence unconfirmed
• = Confined and subject to quarantine
• = See regional map for distribution within the country
• = Occasional or few reports

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