''Tarebia granifera'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

(in the aquarium industry) the quilted melania, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

freshwater snail Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs t ...

with an operculum, an

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

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

Thiaridae Thiaridae, common name thiarids or trumpet snails, is a family of tropical freshwater snails with an operculum, aquatic gastropod mollusks in the superfamily Cerithioidea.MolluscaBase eds. (2021). MolluscaBase. Thiaridae Gill, 1871 (1823). Acce ...

.MolluscaBase eds. (2020). MolluscaBase. Tarebia granifera (Lamarck, 1816). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=397189 on 2020-12-02 This snail is native to south-eastern Asia, but it has become established as 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 multiple other areas. Thiara granifera 011

Subspecies

Subspecies of ''Tarebia granifera'' include: * ''Tarebia granifera granifera'' (Lamarck, 1822) * ''Tarebia granifera mauiensis'' Brot, 1877

Description

A detailed account of the anatomy of ''Tarebia granifera'' was given by

R. Tucker Abbott Robert Tucker Abbott (September 28, 1919 – November 3, 1995) was an American conchology, conchologist and malacology, malacologist. He was the author of more than 30 books on malacology, which have been translated into many languages. Abbot ...

in 1952 Tucker Abbott R. (1952). "A study of an intermediate snail host (''Thiara granifera'') of the Oriental lung fluke (''Paragonimus'')". ''

Proceedings of the United States National Museum The Smithsonian Contributions and Studies Series is a collection of serial periodical publications produced by the Smithsonian Institution, detailing advances in various scientific and societal fields to which the Smithsonian Institution has made ...

'' 102
71
116. together with notes on its biology and bionomics. A dissection guide was provided by Malek (1962).Malek E. A. (1962). ''Laboratory Guide and Notes for Medical Malacology''. 1–154. Burgess Publishing Company, Minneapolis. The maximum height of adult shells of this species from South Africa is from 18.5 mm to 25.1 mm, while in Puerto Rico they can reach up to 35 mm. Two color forms of ''Tarebia granifera'' exist, one has a pale brown

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk ...

and a dark

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

(see photo on the right) and in the other the shell is entirely dark brown to almost black (see photo on the left). Intermediate forms exist.

Distribution

Indigenous distribution

The indigenous distribution of this species includes the general area of these countries:

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

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 ...

, southern

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Society Islands The Society Islands ( , officially ; ) are an archipelago in the South Pacific Ocean that includes the major islands of Tahiti, Mo'orea, Moorea, Raiatea, Bora Bora and Huahine. Politically, they are part of French Polynesia, an overseas country ...

,''Tarebia granifera'' (Lamarck, 1822)
Last modified 3 August 2005, accessed 27 December 2007, Internet Archive

List of non-marine molluscs of Taiwan, Taiwan,Chen K-J. (2003). "A preliminary study on the reproductive ecology of the freshwater snail ''Tarebia granifera'' (Lamarck, 1822) (Prosobranchia: Thiaridae) in Jinlun River, South Eastern Taiwan". MSc thesis, National Sun Yat Sen University, Taiwan. 56 pp.

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

.Ukong S., Krailas D., Dangprasert T. & Channgarm P. (2007). "Studies on the morphology of cercariae obtained from freshwater snails at Erawan waterfall,

Erawan national park Erawan National Park () is a protected area in Western Thailand, in the Tenasserim Hills of Kanchanaburi Province. Founded in 1975, it was the 12th national park of Thailand. History The establishment of the national park was declared in the R ...

, Thailand". '' The Southeast Asian Journal of Tropical Medicine and Public Health'' 38(2): 302–312
PDF

Nonidigenous distribution

''Tarebia granifera'' has become invasive on at least three continents: North and South America and Africa. Initial introductions were presumably via the aquarium trade. Americas: * This species occurs in several states of the U.S.: Florida, Texas,

and

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

. (2008). ''Tarebia granifera''. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Revision Date 4 February 2009. * Many Caribbean islands: **

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

Chaniotis B. N., Butler J. M., Ferguson F. F. & Jobin W. R. (1980). "Bionomics of ''Tarebia granifera'' (Gastropoda: Thiaridae) in Puerto Rico, an Asian vector of ''Paragonimiasis westermani''". '' Caribbean Journal of Science'' 16: 81–89
PDF
**

Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...

– along with ''

Physella acuta ''Physella acuta'' is a species of small, left-handed or sinistral, air-breathing freshwater snail, an Aquatic animal, aquatic gastropod mollusk in the family Physidae. Common names include European physa, tadpole snail, bladder snail, and acute ...

'' it is the most common freshwater snail in Cuba ** The Dominican Republic **

Saint Lucia Saint Lucia is an island country of the West Indies in the eastern Caribbean. Part of the Windward Islands of the Lesser Antilles, it is located north/northeast of the island of Saint Vincent (Saint Vincent and the Grenadines), Saint Vincent ...

Martinique Martinique ( ; or ; Kalinago language, Kalinago: or ) is an island in the Lesser Antilles of the West Indies, in the eastern Caribbean Sea. It was previously known as Iguanacaera which translates to iguana island in Carib language, Kariʼn ...

since 1991 * Central America: Mexico * El Hatillo Municipality, Miranda, Venezuela Africa: *

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

The ''Tarebia granifera'' was reported from South Africa (and Africa) for the first time in 1999 in northern

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

though it was probably introduced sometime prior to 1996. In the 10 years since its discovery it has spread rapidly, particularly northwards, into

Mpumalanga Mpumalanga () is one of the nine provinces of South Africa. The name means "East", or literally "The Place Where the Sun Rises" in the Nguni languages. Mpumalanga lies in eastern South Africa, bordering Eswatini and Mozambique. It shares bor ...

province, the

Kruger National Park Kruger National Park () is a national park in South Africa covering an area of in the provinces of Limpopo and Mpumalanga in the country's northeast. It extends from north to south and from east to west. The administrative headquarters are i ...

and

Eswatini Eswatini, formally the Kingdom of Eswatini, also known by its former official names Swaziland and the Kingdom of Swaziland, is a landlocked country in Southern Africa. It is bordered by South Africa on all sides except the northeast, where i ...

. This spread will doubtless continue into northern South Africa, Moçambique, Zimbabwe and beyond. It has not been possible to calculate the rate of dispersal. Asia: *

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

(non-indigenous)

Ecology

Habitat

In the South Africa, the snail has colonized different types of habitat, from rivers, lakes and irrigation canals to concrete lined reservoirs and ornamental ponds. It reaches high densities, up to 21 000 m², and is likely to impact on the entire indigenous

benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone. The South African indigenous thiarids '' Thiara amarula'', ''

Melanoides tuberculata The red-rimmed melania (''Melanoides tuberculata''), also known as the Malayan livebearing snail or Malayan/Malaysian trumpet snail (often abbreviated to MTS by aquarists), is a species of freshwater snail with an operculum, a parthenogenetic, ...

'', and '' Cleopatra ferruginea'' are considered particularly vulnerable. Most localities in South Africa (93%) lie below an altitude of 300 m above sea level where an estimated area of 39 500 km² has been colonized. The only known localities outside this area are the Umsinduzi River in

Pietermaritzburg Pietermaritzburg (; ) is the capital and second-largest city in the province of KwaZulu-Natal, South Africa after Durban. It was named in 1838 and is currently governed by the Msunduzi Local Municipality. The town was named in Zulu after King ...

and its confluence with the

Umgeni River The Umgeni River or Mgeni River () is a river in KwaZulu-Natal, South Africa. It rises in the "Dargle" in the KZN Midlands, and its mouth is at Durban, some distance north of Durban's natural harbour. It is generally agreed its name means "the ...

which lie closer to 500 m.

(1952) noted that on

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

Island, ''Tarebia granifera'' occurred in streams and rivers at 983 m altitude but that these watercourses were consistently above 24 °C indicating that temperature may be an important determinant of distribution. ''Tarebia granifera'' also occurs in several estuaries along the KwaZulu-Natal coast. Prominent among these is the dense population (±6038 m²) found at a

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

of 9.98‰ (28.5% sea water) in Catalina Bay, Lake St Lucia,

iSimangaliso Wetland Park iSimangaliso Wetland Park is situated on the east coast of KwaZulu-Natal, South Africa, about north of Durban by road. It is South Africa's third-largest protected area, spanning of coastline, from the Mozambique, Mozambican border in the n ...

, KwaZulu-Natal. These records show that ''Tarebia granifera'' is able to colonize

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

and moderately saline habitats and reach high densities there. From observations in

it was suggested that snails could survive temporarily saline conditions for several weeks by burying themselves in the

substratum Substrata, plural of substratum, may refer to: *Earth's substrata, the geologic layering of the Earth *''Hypokeimenon'', sometimes translated as ''substratum'', a concept in metaphysics *Substrata (album), a 1997 ambient music album by Biosphere * ...

, emerging when fresh water returned. In common with other Thiaridae, ''Tarebia granifera'' is primarily a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

species and in South Africa has been collected on a variety of substrata in both natural and artificial waterbodies, e.g. sand, mud, rock, concrete bridge foundations and the concrete walls and bottoms of reservoirs, irrigation canals and ornamental ponds. Many of these habitats were vegetated and the associated vegetation included many types of emergent

monocotyledons Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are flowering plants whose seeds contain only one embryonic leaf, or cotyledon. A monocot taxon has been in use for several decades, but with various ranks and ...

(e.g. ''

Cyperus papyrus ''Cyperus papyrus'', better known by the common names papyrus, papyrus sedge, paper reed, Indian matting plant, or Nile grass, is a species of aquatic plant, aquatic flowering plant belonging to the sedge family Cyperaceae. It is a Hardiness (pla ...

'', ''

Scirpus ''Scirpus'' is a genus of grass-like species in the sedge family Cyperaceae many with the common names club-rush, wood club-rush or bulrush. They mostly inhabit wetlands and damp locations. Description ''Scirpus'' are rhizomatous perennial herbs ...

'' sp., ''

Typha ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrushStreeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ' ...

'' sp., ''

Phragmites ''Phragmites'' () is a genus of four species of large perennial plant, perennial reed (plant), reed Poaceae, grasses found in wetlands throughout temperate and tropical regions of the world. Taxonomy The World Checklist of Selected Plant Famili ...

'' sp.) and

dicotyledons The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...

(e.g. ''

Ceratophyllum demersum ''Ceratophyllum demersum'', commonly known as hornwort (a common name shared with the unrelated Anthocerotophyta), rigid hornwort, coontail, or coon's tail, is a species of flowering plant in the genus ''Ceratophyllum''. It is a submerged, free-f ...

'', ''

Potamogeton crispus ''Potamogeton crispus'', the crisp-leaved pondweed, curly pondweed, curly-leaf pondweed or curled pondweed, is a species of aquatic plant (hydrophyte) native to Eurasia but an introduced species and often a noxious weed in North America. Descr ...

'', ''

Nymphaea nouchali ''Nymphaea nouchali'', often known by its synonym ''Nymphaea stellata'', or by common names blue lotus, star lotus, red water lily, dwarf aquarium lily, blue water lily, blue star water lily or manel flower, is a water lily of genus ''Nymphaea' ...

''). Where densities are high, ''Tarebia granifera'' may also occur on marginal, trailing vegetation and the floating Common Water Hyacinth ''

Eichhornia crassipes ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. It favours turbulent water and tolerates current speeds up to 1.2m.s⁻¹ and possibly greater. This habitat range is similar to that recorded for ''Tarebia granifera'' in Puerto Rico. The major interest in ''Tarebia granifera'' outside Asia today is its invasive ability and its impact on indigenous benthic communities in colonized waterbodies. The pollution tolerance value is 3 (on scale 0–10; 0 is the best water quality, 10 is the worst water quality).Young S.-S., Yang H.-N., Huang D.-J., Liu S.-M., Huang Y.-H., Chiang C.-T. & Liu, J.-W. (2014). "Using Benthic Macroinvertebrate and Fish Communities as Bioindicators of the Tanshui River Basin Around the Greater Taipei Area – Multivariate Analysis of Spatial Variation Related to Levels of Water Pollution". ''

International Journal of Environmental Research and Public Health The ''International Journal of Environmental Research and Public Health'' is a peer-reviewed open access scientific journal that was established in 2004 and is published by MDPI. The editor-in-chief is Paul B. Tchounwou. The journal covers all asp ...

'' 11(7): 7116–7143. . Typically half or more of these snails were buried in the

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

s and were not visible from the surface. This was also noticed in aquaria where they actively buried themselves in sand. Exact proportion of population of ''Tarebia granifera'' that is buried at any time is not known. There is also not known how long can snails remain buried. ''Tarebia granifera'' will die at the temperature 7 °C in aquaria, but they do not live in water temperature under 10 °C in the wild.

Dispersal

It is probable that dispersal of ''Tarebia granifera'' from one waterbody or river catchment to another occurs passively via birds, notably

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

, which eat them and void them later, perhaps in another habitat. Evidence for this comes from the finding of many small ''Tarebia granifera'' 5–7 mm in height and still containing the soft parts in unidentified bird droppings from the bank of the Mhlali River, South Africa. Even though the shell of ''Tarebia granifera'' is thick, most of these juveniles had been partially crushed with only a few still intact. Both the intact and damaged specimens could have been alive when passed and perhaps survived had they been deposited in water. None was large enough to have been reproductively mature (see below) and would have needed to survive in any new habitat for several months before reproducing. Passive dispersal may also occur via weed on boats and boat trailers and via water pumped from one waterbody to another for industrial and irrigation purposes. In the Nseleni River juvenile ''Tarebia granifera'' were commonly found with another invasive snail, ''

Pseudosuccinea columella ''Pseudosuccinea columella'', the American ribbed fluke snail, is a species of air-breathing freshwater snail, an Aquatic animal, aquatic pulmonate gastropod mollusk in the family Lymnaeidae, the pond snails. This snail is an intermediate host f ...

'', on floating clumps of water hyacinth ''Eichhornia crassipes'' which provide a vehicle for rapid downstream dispersal. Once established in a particular waterbody ''Tarebia granifera'' is likely to disperse actively, both up and downstream in the case of flowing systems, as far as environmental factors like current speed and food availability will allow. The snail's tolerance of turbulent, flowing water was demonstrated by Prentice (1983). who reported it migrating upstream on the Caribbean island of

at a rate of 100 m month⁻¹ in streams discharging up to 50 L.s⁻¹. In KwaZulu-Natal it has been collected in water flowing at up to 1.2 m.s⁻¹ which is likely to exceed the current speeds of at least the lower and middle reaches of many rivers and streams in South Africa making these watercourses open to colonization. The sole of ''Tarebia granifera'' is proportionally small when compared to other thiarids and smaller snails with their higher coefficients were less able to grip the substratum in the face of moving water and so did not disperse as effectively as larger ones.

Density

In Florida, Tucker Abbott (1952) recorded a

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

of ''Tarebia granifera'' 4444 m⁻² which falls within the range of densities measured with a Van Veen grab in a number of sites in northern KwaZulu-Natal, where densities were measured from 843.6 ±320.2 m⁻² to 20764.4 ±13828.1 m⁻². The site with such high density was non-flowing, devoid of rooted vegetation but it was shaded by trees ('' Barringtonia racemosa'') and by floating ''

habitat heterogeneity Homogeneity and heterogeneity are concepts relating to the uniformity of a substance, process or image. A homogeneous feature is uniform in composition or character (i.e., color, shape, size, weight, height, distribution, texture, language, inc ...

and food availability. Despite the high densities recorded in the Nseleni River, indigenous invertebrates were still present in the sediments including: bivalve '' Chambardia wahlbergi'',

chironomid Chironomidae , commonly known as non-biting midges or chironomids , are a family of Nematoceran flies with a global distribution. They are closely related to the families Ceratopogonidae, Simuliidae, and Thaumaleidae. Although many chironomid s ...

oligochaetes Oligochaeta () is a subclass of soft-bodied animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadril ...

(tubificids) and burrowing

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

were also found but in low numbers. The low densities of ''Tarebia granifera'' reported for the Mhlatuze River, South Africa may have been influenced by nearby

sand mining Sand mining is the extraction of sand, mainly through an open pit (or sand pit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds. Sand is often used in manufacturing, for example as an abrasive or in conc ...

activities or, more likely, high flows and mobile sediments, but they nevertheless approach those recorded by Dudgeon (1980)Dudgeon D. (1980). "The effects of water level fluctuations on a gastropod community in the rocky marginal zone of Plover Cove reservoir, Hong Kong". '' International Journal of Ecological and Environmental Sciences'' 8: 195–204. for ''Tarebia granifera'' in its native

(18–193 m⁻²). Little is known of the long term population fluctuations of ''Tarebia granifera'' and findings seem to be contradictory. Studies in Cuba (Yong et al. (1987), Ferrer López et al. (1989), Fernández et al. (1992)) indicate that the snail lives for more than a year though maximum densities were recorded at different times of the year in different habitats. Using a

catch per unit effort In fisheries and conservation biology, the catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species' true abundance. A decr ...

netting technique, Yong et al. (1987) and Ferrer López et al. (1989) found highest densities in summer when temperatures reached their maximum whereas Fernández et al. (1992) found highest densities in November (late autumn) when temperatures reached their minimum. Fernández et al. (1992) also suggested that ''Tarebia granifera'' density was positively correlated with Ca²⁺ concentrations and negatively with NH₄ concentrations. Recent surveys by Vázquez et al. (2010) of

Pinar del Río Province The Pinar del Río Province is one of the 15 provinces of Cuba. It is at the western end of the island of Cuba. The capital and largest city is Pinar del Río (191,081 pop. in 2022). Geography The Pinar del Río province is Cuba's westernmost p ...

, Cuba have reported population densities of ''Tarebia granifera'' of 85 individuals/m², well above those of its endemic relatives (5 individuals/m²).

Feeding habits

''Tarebia granifera'' feeds on algae,

diatoms A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

Life cycle

''Tarebia granifera'' is both

parthenogenetic Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...

and

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...

, although males have been reported. These are characteristics which are undoubtedly key to its success as an invader. For example, no males have been found amongst hundreds dissected from KwaZulu-Natal, it is probable that a few are present. Males were found in most (6/7) populations examined in

but were generally uncommon at up to 22.7% of the population (mean 4.6%). Live sperm were present in the testes of these males but the

genitalia A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting ...

were apparently non-functional. R. Tucker Abbott (1952) failed to find sperm in the gonads of male ''Tarebia granifera'' from Florida. Most ''Tarebia granifera'' are therefore clones of the female parent.

Embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

s develop in a brood pouch. This pouch is a compartmentalized structure lying immediately above the

oesophagus The esophagus (American English), oesophagus (British English), or œsophagus ( archaic spelling) ( see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), colloquially known also as the food pipe, food tube, or gullet, ...

and develops only after the snail has reached maturity. Its size expands as the number of embryos increases. ''Tarebia granifera'' has 1–77 embryos in its brood pouch. Tucker Abbott (1952), Chaniotis et al. (1980) and WHO (1981)W.H.O. (1981). "Data sheet on the biological control agent ''Thiara granifera'' (Lamarck)".

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

, Geneva, VBC/BCDS/81.17. cite the same statistic that females can give birth to one juvenile every 12 hours. Young snails emerge through a birth pore on the right side of the head. The newborn shell is <1–2 mm in height with between 1.5 and 4.8 whorls. The size of juveniles at birth is 0.7–2.1 mm. According to Chen (2003) these newborns have a high survival rate in the field. Attainment of

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

in ''Tarebia granifera'' is generally indicated by the size of the smallest snail observed to give birth rather than a histological assessment of the development of the gonad and associated reproductive structures. Appleton & Nadasan (2002) estimated onset of maturity at 10–12 mm shell height but unpublished data suggest a height closer to 8 mm in line with other published studies. Tucker Abbott (1952) estimated sexual maturity at between 5.5 and 8.0 mm at different stations over a short stretch of river in Florida. Chaniotis et al. (1980) gave a similar estimate of 6.0–7.0 mm from a cohort of laboratory-bred snails in Puerto Rico. Appleton et al. (2009) extrapolated data by Yong et al. (1987),Yong M., Sanchez R., Perera G., Ferrer R. & Amador O. (1987). "Seasonal studies of two populations of ''Tarebia granifera''". ''

Walkerana ''Walkerana'' is a genus of frogs in the family Ranixalidae. The genus is endemic to the Western Ghats in the states of Kerala and Tamil Nadu, India. It was erected in 2016 to host three species of ''Indirana'' that represented a genetically an ...

'' 2: 159–163. Ferrer López et al. (1989) Ferrer López J. R., Perera de Puga G. & Yong Cong M. (1989). "Estudio de la morfometría de los 4 poblaciones de ''Tarebia granifera'' en condiciones de laboratorio". '' Revista Cubana de Medicina Tropical'' 43: 26–30. and by Fernández et al. (1992) Fernández L. D., Casalis A. E., Masa A. M. & Perez M. V. (1992). "Estudio preliminar de la variación de ''Tarebia granifera'' (Lamarck), Río Hatibonico, Camagüey". '' Revista Cubana de Medicina Tropical'' 44: 66–70. and they resulted that sexual maturity is reached at an age of about five months. Reported variation in maturation period varies from 97 to 143 days (3.2–4.8 months) under the laboratory conditions to 6–12 months, also from laboratory data. It is difficult to relate shell size at the onset of maturity to age since the size structure of populations vary over time and from one locality to another. Dissection of ''Tarebia granifera'' showed

blastula Blastulation is the stage in early animal embryonic development that produces the blastula. In mammalian development, the blastula develops into the blastocyst with a differentiated inner cell mass and an outer trophectoderm. The blastula (fr ...

stage embryos in the brood pouches of snails as small as 8 mm shell height. Small numbers of shelled embryos, including

veliger A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod taxono ...

s, were found in snails of 10–14 mm but became more plentiful in snails >14 mm and especially those >20 mm. Importantly, unshelled embryos (blastula,

gastrula Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of Cell (biology), cells), or in mammals, the blastocyst, is reorganized into a two-layered or three-layered e ...

and

trochophore A trochophore () is a type of free-swimming planktonic marine larva with several bands of cilia. By moving their cilia rapidly, they make a water eddy to control their movement, and to bring their food closer in order to capture it more easily. ...

stages) were not found in snails >16 mm and the numbers of shelled embryos themselves decreased in the largest snails, >24 mm. This suggests that differentiation of germinal cells in the ovary and their subsequent arrival in the brood pouch as blastulae is not a continuous process over a breeding season but occurs as one or more 'cohorts' or 'pulses' which stop before the birth rate of young snails reaches its maximum. So it seems that while the first birth may occur in snails as small as 8 mm, these are few and most juveniles are born to snails >14 mm. The size of the shell of the parent at peak release of juveniles is 24.0 mm. The

reproductive biology Reproductive biology includes both sexual and asexual reproduction. Reproductive biology includes a wide number of fields: * Reproductive systems * Endocrinology * Sexual development (Puberty) * Sexual maturity * Reproduction * Fertility H ...

of ''Tarebia granifera'' needs to be investigated in detail before its

population dynamics Population dynamics is the type of mathematics used to model and study the size and age composition of populations as dynamical systems. Population dynamics is a branch of mathematical biology, and uses mathematical techniques such as differenti ...

can be properly interpreted from quantitative sampling.

Parasites

''Tarebia granifera'' serves as the first

intermediate host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

for a variety of

trematodes Trematoda is a class of flatworms known as trematodes, and commonly as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is a moll ...

in its native south east Asia. Amongst these are several species of the family

Heterophyidae Heterophyidae is a family of intestinal trematodes in the order Plagiorchiida. Description: " Tegument covered by spines. Oral sucker not armed or armed by circumoral spines. Pharynx presented. Genital synus presented. Ventral and genital s ...

some of which have been reported as opportunistic infections in people, and another, '' Centrocestus formosanus'' (Nishigori, 1924), is an important gill parasite of fish. ''Tarebia granifera'' also serves as intermediate host for the philopthalmid eyefluke '' Philopthalmus gralli'' Mathis & Ledger, 1910 which has recently (2005) been reported affecting

ostrich Ostriches are large flightless birds. Two living species are recognised, the common ostrich, native to large parts of sub-Saharan Africa, and the Somali ostrich, native to the Horn of Africa. They are the heaviest and largest living birds, w ...

es ''

Struthio camelus The common ostrich (''Struthio camelus''), or simply ostrich, is a species of flightless bird native to certain areas of Africa. It is one of two extant species of ostriches, the only living members of the genus '' Struthio'' in the ratite group ...

'' on farms in Zimbabwe. The snail host implicated in this outbreak was ''Melanoides tuberculata'' but the rapid spread and high population densities achieved by ''Tarebia granifera'', which appears to be replacing ''Melanoides tuberculata'' in South Africa, may exacerbate the problem in the future. For many years ''Tarebia granifera'' was believed to be an intermediate host for the Asian lungfluke ''

Paragonimus westermani ''Paragonimus westermani'' (Japanese lung fluke or oriental lung fluke) is the most common species of lung fluke that infects humans, causing paragonimiasis. Human infections are most common in eastern Asia and in South America. Paragonimiasis ...

'' (Kerbert, 1878), but Michelson showed in 1992 that this was erroneous.Michelson E. (1992). "''Thiara granifera'': a victim of authoritarianism?" '' Malacological Review'' 25: 67–71.

Other interspecific relationships

''Tarebia granifera'' have been associated with the disappearance of two indigenous benthic gastropod species from rivers in

and have displaced the vegetation-associated pulmonate ''

Biomphalaria glabrata ''Biomphalaria glabrata'' is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails. ''Biomphalaria glabrata'' is an intermediate snail host for the trematode '' S ...

'' from streams and ponds on several Caribbean islands.Samadi S., Balzan C., Delay B. & Pointier J.-P. (1997). "Local distribution and abundance of thiarid snails in recently colonized rivers from the Caribbean area". ''Malacological Review'' 30: 45–52. Although the responsible mechanism is not understood, this has led to suggestions that it could be useful as a

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

agent in snail control operations within integrated

schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever is a neglected tropical helminthiasis, disease caused by parasitism, parasitic Schistosoma, flatworms called schistosomes. It affects both humans and animals. It affects ...

control programmes. They probably also

compete Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, individ ...

for space and resources (e.g. food) with indigenous infaunal and epifaunal invertebrates, especially where its densities are high. Under such conditions it is likely to alter the structure and

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

of the entire benthic communities of invaded habitats and perhaps the vegetation-associated communities as well. Anecdotal reports and observations suggest that in

the indigenous thiarid ''

'' is becoming less common and pressure from the spread of ''Tarebia granifera'', particularly at high densities, is a possible explanation. Like ''Tarebia granifera'', ''Melanoides tuberculata'' is parthenogenetic and ovoviviparous, grows to a similar size, are similar in size at first birth and juvenile output. Data from several habitats where the species occur sympatrically show however that in all such situations ''Tarebia granifera'' becomes numerically dominant. ''Tarebia granifera'' is likely to impact on another South-African indigenous thiarid, the poorly known '' Thiara amarula'' in the saline St. Lucia estuary system. Studies on the ecological impact of ''Tarebia granifera'' are urgently needed.

Human importance

In addition to its role as intermediate host for several economically important trematode species, ''Tarebia granifera'' has colonized

water reservoir A reservoir (; ) is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupt ...

s, dams and ponds on the premises of three large industrial plants in northern KwaZulu-Natal and been pumped out of at least one of them, blocking

water pipe Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water deliv ...

s and damaging equipment. This generally happens when snail densities are high and the damage is due to individuals being crushed so that pieces of shell and soft tissue are carried into machinery. Details of the nature and extent of this damage and the costs incurred are not available. There is no doubt that ''Tarebia granifera'' is able to pass unharmed through

pumps A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic or pneumatic energy. Mechanical pumps serve in a wide range of applications such ...

, probably as juveniles.

References

This article incorporates CC-BY-3.0 text from references.Appleton C. C., Forbes A. T.& Demetriades N. T. (2009). "The occurrence, bionomics and potential impacts of the invasive freshwater snail ''Tarebia granifera'' (Lamarck, 1822) (Gastropoda: Thiaridae) in South Africa". ''

Zoologische Mededelingen ''Zoologische Mededelingen'' was a peer-reviewed open access scientific journal publishing papers and monographs on animal systematics. The publisher was the National Museum of Natural History Naturalis in the Netherlands. The first issue appeared ...

'' 83. http://www.zoologischemededelingen.nl/83/nr03/a04Vázquez A. A. & Perera S. (2010). "Endemic Freshwater molluscs of Cuba and their conservation status". ''

Tropical Conservation Science Mongabay (mongabay.com) is an American conservation news web portal that reports on environmental science, energy, and green design, and features extensive information on tropical rainforests, including pictures and deforestation statistics f ...

'' 3(2): 190–199
HTMPDF

Subspecies

Description

Distribution

Indigenous distribution

Nonidigenous distribution

Ecology

Habitat

Dispersal

Density

Feeding habits

Life cycle

Parasites

Other interspecific relationships

Human importance

References

Further reading