Search

The widespread Pomacea canaliculata and Pomacea maculata in North America and Asia have caused significant adverse effects on the local ecological environment and residents' health. Timely knowledge of the distribution of eggs from the two Pomacea spp. in a certain region can effectively reduce the cost of treatment and improve prevention effectiveness. Most of the existing methods are only able to identify eggs from the two Pomacea spp. or detect them in specific but not natural environments while they cannot achieve good results in the face of a complex real-world scene. This letter proposes a model for detecting eggs from the two Pomacea spp. based on dynamic convolution and multiscale feature fusion. The model can identify and locate the eggs of the two Pomacea spp. effectively. At the same time, we combined the proposed model with scale invariant feature transform (SIFT) algorithm to design a system for counting eggs of the two Pomacea spp., which can automatically identify the eggs in the actual natural environment and alleviate duplicate counting caused by image acquisition. Besides, we also built a dataset of 20,000 images of Pomacea canaliculata eggs and Pomacea maculata eggs from unmanned aerial vehicle (UAV) aerial photography. Experimental results showed that the proposed deep learning model has a better performance than others, and the proposed computer vision system can be successfully applied to support Pomacea spp. disease management.

Invasive species threaten biodiversity, ecosystem functions, and human health around the world. Accurate and reliable species delineation and identification are prerequisites for any effort to control the introduction of new species and the spread of those already introduced. The advent of DNA assisted taxonomic tools has fueled the development of diverse and innovative approaches often touted as simple, inexpensive, and universally applicable for addressing impediments to rapid identification of non-native species. Ampullariidae (apple snails) are a family of freshwater snails with at least five species that have been introduced outside their native range and a prime example of how taxonomic uncertainty may hamper our understanding of invasion biology. Matsukura et al. (Appl Entomol Zool 43(4):535–540, 2008) and Cooke et al. (Conserv Genet Resour 4(3):591–593, 2012) developed species-specific PCR primers as rapid, simple, and inexpensive approaches to distinguishing among and identifying the most notorious and widespread invasive apple snails, Pomacea canaliculata and Pomacea maculata, and a third species in the aquarium trade, Pomacea diffusa. Neither approach was evaluated within the context of the overall genetic diversity of the target species, or with consideration for the species diversity within the family. To evaluate both shortcut approaches, the primers were tested for their utility in delineating and identifying the target species and other closely related taxa, including 24 apple snails representing 21 species. The results indicate that the primers are of limited taxonomic utility, and fail to consistently identify the target taxa, or congenerics. More importantly, use of these primers without additional data leads to misidentifications, potentially endangering native biodiversity and allowing novel introduced species to go undetected.

Pomacea species, also known as apple snails, are highly invasive freshwater organisms now occurring in Central and North America, Asia and Europe. Species misidentification within the genus has hampered efforts to manage their spread and impact, and thus Pomacea maculata have received much less attention that P. canaliculata. Species Distribution Models are well suited for a global screening for suitable regions for the establishment of apple snails. Here, a global distribution model for the distribution of P. maculata based on an extensive database allowed us to identify current and future potential receptor freshwater ecoregions (FEOws) and to set priorities for the development of early warning strategies under climate change scenarios. Model performance was adequate, predicting accurately most invaded FEOWs across the world. Performing a global balance for climate change scenarios, and considering only FEOWs with medium and high ecoregional susceptibility (ES), the potential native distribution of P. maculata is reduced in ca. 945,701 km2, while the exotic potential distribution area increases in 1,118,111 km2. To minimize risks of future invasions, uninvaded FEOWs with both high values of ES and a predicted increase in environmental quality for the establishment of P. maculata were identified across the globe. The development of early warning schemes aiming to detect the initial phase of invasions may provide a unique opportunity for control of this highly invasive species before a much damage to the socio-ecological system is inflicted.

maculata Pomacea maculata Perry, 1810. New type material ��� neotype (Hayes et al. 2012: 730): NHMUK 1854.12. 4.313. Remarks. Hayes et al. (2012: 730) designated the same specimen as the neotype of gigas Spix, insularum d���Orbigny and maculata Perry, thereby rendering them objective synonyms., Published as part of Cowie, Robert H., 2015, The recent apple snails of Africa and Asia (Mollusca: Gastropoda: Ampullariidae: Afropomus, Forbesopomus, Lanistes, Pila, Saulea): a nomenclatural and type catalogue. The apple snails of the Americas: addenda and corrigenda, pp. 1-92 in Zootaxa 3940 (1) on page 62, DOI: 10.11646/zootaxa.3940.1.1, http://zenodo.org/record/288204, {"references":["Perry, G. (1810 - 1811 a) Arcana; or the museum of natural history. Stratford, London, 84 pls. [un-numbered], associated text.","Hayes, K. A., Cowie, R. H., Thiengo, S. C. & Strong, E. E. (2012) Comparing apples with apples: clarifying the identities of two highly invasive Neotropical Ampullariidae (Caenogastropoda). Zoological Journal of the Linnean Society, 166 (4), 723 - 753. [December issue] http: // dx. doi. org / 10.1111 / j. 1096 - 3642.2012.00867. x"]}

13 pages, 4 figures, 1 table, supplementary information https://doi.org/10.1007/s10750-022-04996-5.-- Data availability: The isotopic values generated from this study are available on request from the corresponding author, The only wetland in Europe colonized successfully by the apple snail Pomacea maculata Perry, 1810, is the Ebro Delta (Spain). After 10 years, it has become widespread there, despite significant eradication attempts. In spite of its great negative ecological and economic impacts, its incorporation into food webs can result in an abundant potential resource for native and exotic predators. We identified the potential predators, including fishes, amphibians, crustaceans, birds, turtles and mammals in natural conditions using stable isotopic analyses (δ13C and δ15N). Six predator species, three native (two birds and one frog) and three invasive (one crustacean, one turtle and one mammal), were confirmed to consume apple snails. None of the 10 fish species analyzed consumed apple snails, although some have been previously observed consuming this snail under laboratory conditions. This study emphasizes the need to assess the consumption of apple snail, as well as other invasive organisms, by potential predators in natural conditions to confirm the establishment of new trophic relationships and to understand whether these potential predators actually act as biological control agents in nature, This work was funded by SEO/BirdLife and Forestal Catalana. JN was supported by Spanish National Program Ramón y Cajal (RYC-2015-17809). MV was supported by a predoctoral fellowship of the FPU program of the Spanish Government (FPU18/01775), With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

Special issue Ocean Noise: From Science to Management.-- 15 pages, 8 figures, Global change is the origin of increased occurrence of disturbance events in natural communities, with biological invasions constituting a major threat to ecosystem integrity and functioning. The apple snail (Pomacea maculata) is a freshwater gastropod mollusk from South America. Considered one of the 100 most harmful invasive species in the world, due to its voracity, resistance, and high reproductive rate, it has become a global problem for wetland crops. In Catalonia, it has affected the rice fields of the Ebre Delta since 2010 with significant negative impact on the local economy. As a gastropod mollusc it possesses statocysts consisting of a pair of sacs, one located on each side of the foot, that contain multiple calcium carbonate statoconia. This study shows the first ultrastructural images of pathological changes in the sensory epithelium of the statocyst of apple snail adults with an increase in the severity of the lesions over time after exposure to low frequency sounds. Sound-induced damage to the statocyst could likely result in an inhibition of its vital functions resulting in a potential reduction in the survival ability of the apple snail and lead to an effective mitigation method for reducing damage to rice fields, With the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S)

The most noxious apple snails (Pomacea canaliculata and P. maculata) native to South America, currently has two distinct invaded ranges in China and the United States. Whether the environmental niches of the two closely related species have changed or remained stable (niche conservatism hypothesis) during the invasion process has become an important issue in forecasting their potential geographic distributions. For each Pomacea snail, two ecological niche models (ENMs, employing BIOMOD2) were generated based on bioclimatic variables and occurrence records in: (1) the native range; (2) the different invasive range. Conservation of ecological niche between the native and invasive snail populations were then tested by principal component and niche dynamics analysis. According to all models, precipitation contributed most to distribution of P. maculata, whereas low temperature was another most influential factor for spread of P. canaliculata. Niche conservatism were indicated by niche similarity tests and high niche stability for both Pomacea snails during their invasions in two regions. Niche expansions of P. canaliculata were relatively larger than unfilling values, whereas niche expansions of P. maculata were lower than unfillings. High niche unfilling for P. maculata in the United States revealed a great potential for further expansion in this region. We discuss the possible roles of physiological tolerances, genetic variation, residence time and hybridization in shaping niche changes for Pomacea snails during their invasion processes. Findings of this work can improve the understanding of potential mechanisms for niche differentiation and provide a theoretical basis for forecasting the invasion potential of Pomacea snails.

This study was focused on molluscicidal effect and feeding deterrent activity of saponin from five different plant materials; Andrographis paniculata, Entada spiralis, Ficus deltoidea, Furcraea selloa and Ipomoea batatas. Crude plant extracts were prepared from plant powders using methanol. The crude extracts were then tested on Pomacea maculata using five different concentrations (5, 10, 15, 20 and 25 ppm, respectively) against niclosamide (control). After 72 h of exposure, the highest percentage of mortality of 80% was achieved from 15 ppm of F. selloa. Two analyses were conducted to observe the feeding deterrent activity and after 24 h, both analyses demonstrated the feeding deterrent activity in both crude extracts (F. selloa and E. spiralis) similar in niclosamide.

Herein we provide direct evidence for the consumption of Pomacea maculata (Giant Applesnail) eggs by ants in the genus Crematogaster. The observations were made during removal of snail egg masses at the Hudson Woods Unit of the Texas Mid-Coast National Wildlife Refuge, TX. We observed acrobat ants (Crematogaster sp.) removing snail eggs from an egg mass and carrying eggs back to their nest. While predation on Pomacea applesnail eggs has been reported elsewhere, to our knowledge this is the first time that it has been observed in North America.

Temnocephala iheringi Haswell, 1893 was recorded in Marisa planogyra Pilsbry, 1933 and Pomacea maculata Perry, 1810. Also, Temnocephala amatoi sp. nov. was described from Pomacea scalaris (d’Orbigny, 1835). The mollusks were collected from temporary ponds at Ypiranga Farm, Poconé, Mato Grosso, Brazil. The new species differs from six other species of Temnocephala Blanchard, 1849 epibionts on molluks by having the following combination of characters: 1. a short and curved cirrus; 2. a narrow introvert with approximately 22 longitudinal rows of spines with 13 spines each; 3. internal spines with a narrow base, longer on the base of the introvert and smaller in the distal portion; 4. a single and asymmetrical vaginal sphincter and; 5. elliptical, longer than wide epidermal ‘excretory’ syncytial plates (EPs) with a excretory pore displaced to the anterior portion of the plate. Temnocephala lamothei Damborenea & Brusa, 2008 has a curved cirrus, similar in size to the new species’ cirrus. However, the introvert is not swollen with an oblique proximal margin, marked with a thickened oblique ring and two rows of 45–50 thin spines, differentiating the species from T. amatoi sp. nov.. When comparing the specimens of T. iheringi from Poconé with the redescription of the species from Southern Brazil previously published by the authors, we found significant intraspecific variation in the size of the adhesive disk, pharynx length, shaft and introvert length, spines of the introvert length, as well as differences in the number of paranephrocytes. The size of the EPs and, when comparing with published data from Uruguayan and Argentinean specimens, the body size also showed important differences. We hypothesize that the host species may be the cause of the intraspecific variations found. Overall, the record of two new hosts for T. iheringi, the intraspecific variation found in this species and its geographical distribution being expanded 418 km further to the north, together with the description of a new species, add acknowledgment to the Rhabdocoela fauna in the Brazilian Pantanal.

The Tonle Sap Lake in Cambodia is a crucial freshwater biodiversity hotspot and supports one of the world’s largest inland fisheries. Within the Tonle Sap basin, freshwater molluscs provide vital ecosystem services and are among the fauna targetted for commercial harvesting. Despite their importance, freshwater molluscs of the Tonle Sap basin remain poorly studied. The historical literature was reviewed and at least 153 species of freshwater molluscs have been previously recorded from throughout Cambodia, including 33 from the Tonle Sap basin. Surveys of the Tonle Sap Lake and surrounding watershed were also conducted and found 31 species, 15 bivalves (five families) and 16 gastropods (eight families), in the Tonle Sap basin, including three new records for Cambodia (Scaphula minuta, Novaculina siamensis, Wattebledia siamensis), the presence of globally invasive Pomacea maculata and potential pest species like Limnoperna fortunei. This study represents the most comprehensive documentation of freshwater molluscs of the Tonle Sap basin, and voucher specimens deposited at the Inland Fisheries Research and Development Institute, Cambodia, represent the first known reference collection of freshwater molluscs in the country. In order to combat the combined anthropogenic pressures, including invasive species, climate change and dams along the Mekong River, a multi-pronged approach is urgently required to study the biodiversity, ecology, ecosystem functioning of freshwater molluscs and other aquatic fauna in the Tonle Sap basin.

The blue crab, Callinectes sapidus is an invasive species in the Mediterranean region. In Ebro Delta bays, it poses an important risk for the cultivation of Mediterranean mussel (Mytillus galloprovincialis) and Pacific oyster (Crassostrea gigas). Besides, the species thrives in the Ebro River hosting abundant populations of apple snail (Pomacea maculata) and Asian clam (Corbicula fluminea). Food-preference experiments were conducted to assess the effect of predator and prey sizes and prey type (M. galloprovincialis vs. C. gigas and P. maculata vs. C. fluminea) in predation patterns and its possible causes. Our results show that except for the Pacific oyster, which attains protection at sizes of 50–70 mm and was little consumed (0–16%), the other preys are readily predated, at variable rates (mussels: 38–96%; apple snail: 58–93%, and Asian clam: 67–100%), depending on predator and prey sizes. Juveniles and young blue crab adults showed greater consumption of small and medium mussels and a similar trend occurred with Asian clam. In contrast, large and medium apple snails were more heavily predated by adult blue crabs. Species comparisons also showed higher predation of mussels than oysters (71 vs. 8%), and of apple snail than Asian clam (99 vs. 72%). Once the shell barrier was removed, preference for mussels was still preserved, suggesting a nutritional preference. Our results point the need of fishing blue crab in marine areas to prevent losses in mussel production and highlight the potential control exerted over undesired invasive mollusk species. info:eu-repo/semantics/acceptedVersion

Pomacea maculata (Giant Apple Snail) is a freshwater snail from South America that is an invasive species on the Gulf of Mexico coastal plain. A sister species has been shown to prey on amphibian eggs in Asia. To test whether the Giant Apple Snail will prey on amphibian eggs, we presented eggs of Lithobates palustris (Pickerel Frog), Lithobates pipiens (Northern Leopard Frog), and Anaxyrus americanus (American Toad) to Giant Apple Snails in a laboratory experiment. Giant Apple Snails ate the eggs of all 3 species.

Pomacea spp. are freshwater gastropods that significantly reduce rice productivity around the world, particularly in Asian countries. Pomacea maculata was first reported in Europe in 2009 in the rice fields of the Ebro Delta, Tarragona (Catalonia), Spain. At present, tea seed (Camellia oleifera) saponins are the only authorized treatment by the Spanish agriculture authorities, but due to its comparatively high toxicity to non-target species such as fish, more environmental-friendly products are urgently needed. This study evaluated the performance of a novel molluscicide based on modified saponins derived from quinoa (Chenopodium quinoa) husks against Pomacea maculata under laboratory and field conditions in the Ebro Delta. Under laboratory conditions, the molluscicide killed 100% of the P. maculata above 7 ppm of saponins after 72 h. Field trials performed in three rice fields showed that after 96 h the molluscicide killed 88, 89 and 93% of P. maculata at doses of 6.5, 7.2 and 7.7 ppm saponin, respectively. Toxicological assays showed that the product is highly safe for aquatic environments, with an effect concentration of (EC50) >36 mg saponins/L for crustaceans (Daphnia) and algae (Selenastrum capricornutum) and a lethal concentration (LC50) against common carp >36 mg saponins/L. Studies on rats, rabbits and guinea pigs showed that the molluscicide is generally non-hazardous for acute oral toxicity, slightly hazardous for acute dermal toxicity, a moderate irritant for acute eye irritation/corrosion, a non-irritant for acute dermal irritation/corrosion and a non-skin sensitizer. These results suggest that this novel molluscicide may be a viable product to safely control P. maculata in rice fields.

The impacts of non-native species on native ecosystems can be substantial, and effective management strategies often require a comprehensive understanding of species biology and ecology within the invaded range. The island apple snail Pomacea maculata is an invasive species known to alter the structure and function of wetland habitats. Researchers first reported island apple snails in the United States in Tallahassee, FL, in 2002 and subsequently observed this species in South Carolina (SC) in 2008. The objectives of this study were to document the spatial distribution, phenology and life history, and habitat preference of island apple snails, as well as its association with co-occurring gastropods in SC. Populations were surveyed in stormwater retention ponds throughout coastal SC, where surveyors documented the numbers of live specimens, sex ratios, and the substrate types on which island apple snails deposited egg clutches. The high abundances and year-round presence of egg clutches observed in this study indicate that these populations are successfully reproducing throughout the year, although egg clutch abundance was positively correlated with air temperature. Overall, this study found higher numbers of female P. maculata than males, and that females preferred to lay egg clutches on culverts as opposed to other available substrates. In addition to P. maculata, four other non-native gastropods were documented in stormwater retention ponds. Among these, Melanoides tuberculata and Pyrgophorus parvulus are potential vectors for multiple human diseases and had never before been reported in SC. Understanding the current distribution and life history traits of P. maculata is important for determining the potential for further spread and providing opportunities to protect healthy, natural ecosystems from the impacts of non-native species.

The introduction and spread of non-native species represents a significant threat to freshwaters. Non-native Pomacea are a recent and detrimental gastropod invader, altering habitats, biodiversity, and ecological function. Despite large size, adult Pomacea spp. may be cryptic but their egg masses, which are species specific in color and size, appear useful in determining presence and spatial distribution within invaded areas. We used a combination of annual (2013–2016) and monthly (April 2016–March 2017) shoreline transect surveys to determine the distribution of Pomacea spp. egg masses, along with habitat and water quality data, in Lake Seminole, GA, USA. Surveys identified invasive P. maculata and native P. paludosa, and provided evidence for rapid dispersal of P. maculata. Egg masses of both species occupied a wide range of emergent surfaces across the lake. Physicochemical measures suggest elevated specific conductivity corresponds with Pomacea presence. Temperature correlated with monthly variation of egg mass; however, egg masses were observed at water temperatures of 11.3 °C, below reported limits. Pomacea maculata dispersal throughout Lake Seminole is rapid, and shoreline classification and physicochemical conditions are influencing the on-going dispersal. Continued expansion of this invasive herbivore could have ecosystem-level consequences in Lake Seminole and other invaded waters across the southeast US.

Low, L. and Anderson, C.J., 2017. The threat of a nonnative, invasive apple snail to oligohaline marshes along the northern Gulf of Mexico. Aquatic invasive species continue to be a persistent ecological problem. Management of these species requires understanding of their impact and the conditions favorable for their occurrence. Pomacea maculata is an invasive, nonnative freshwater apple snail threatening wetlands through substantial herbivory. Recent detection of P. maculata in coastal Alabama has raised concerns regarding the susceptibility of estuarine marshes in Mobile Bay and the northern Gulf of Mexico. To evaluate this threat, mesocosms were created to examine snail response to the combined effects of salinity and plant species common to estuaries throughout the region. Over a 5-week period, snails in brackish-water mesocosms (∼10 parts per thousand [ppt], with Juncus roemerianus or Cladium jamaicense) became dormant and neither fed nor reproduced. Snails in freshwater mesocosms (

Dispersal and local environmental factors are major determinants of invasive species distribution. We examined how both dispersal-related geospatial characteristics and environmental factors influence an ongoing invasion of wetlands in a south-central Florida ranchland by non-native apple snails (Pomacea maculata, Ampullariidae). We found P. maculata in 73 (43%) of a random set of 171 wetlands in 2014. We used model selection to evaluate multiple hypotheses of predictors of P. maculata occurrence in 95 wetlands with standing water, including spatially-explicit distances in ditches from wetlands to the presumed entry point, Euclidean (overland) distances, presence/absence of ditches in wetlands, and environmental variables (e.g. pH). We also performed a 5-month field experiment in 20 wetlands to evaluate if snail absence was associated with conditions that limit survival and growth (i.e. unfavorable habitats). Snail occurrence was primarily associated with presence of ditches in wetlands and more neutral wetland pH. These variables more plausibly explained snail occurrence than did Euclidean (overland) distance and minimum ditch travel (rectilinear) distance from propagule sources (a major waterway). Wetland pH best explained survival and growth under the experimental conditions. We found no evidence that prior occupancy by conspecifics affected survival and growth, suggesting that dispersal limitation may contribute to lack of occupancy of wetlands, despite suitable pH. Our study supports man-made conduits as facilitators of dispersal by non-native species, where environmental characteristics (here pH) then also affect colonization within habitats. An understanding of both dispersal mechanisms and local environmental factors is necessary to better predict invasive species distribution.

Climate change has dramatically altered freshwater ecosystems and will continue to affect them further. As water-level fluctuations increase in frequency and intensity, the tolerance of aquatic organisms to abiotic stressors will become critical determinants of survival. Apple snail species in the genus Pomacea (Ampullariidae) live in freshwater throughout the tropics and subtropics, but deposit egg clutches on terrestrial substrates. Two species, Pomacea canaliculata and Pomacea maculata, are amongst the world’s most invasive species and are expanding their invasive ranges. To evaluate their survival during extreme dry-down conditions in their native range, we collected 156 apple snails (Pomacea spp.) from 4 permanent water bodies in Uruguay and buried them in dry sand to simulate drought. We placed the snails outside, sheltered from sun and rain (ambient temperature: 15.2–28.1°C, ambient humidity: 44.9–100.6% below sand surface, 34.2–98.7% in outside air), and checked survival daily. Genetic ide...

The vulnerability of gastropods to their predators varies with life history traits such as morphology, body size, behavior, and growth rates as well as predator size. A recent study suggested that the invasive apple snail, Pomacea maculata, was considerably more vulnerable to crayfish predators than the native Florida apple snail, P. paludosa. The difference was hypothesized to be caused by the relatively small hatchling size of P. maculata. To test this hypothesis, we conducted a series of feeding assays designed to quantify maximum feeding rates and selective foraging of crayfish on apple snails. The rate at which crayfish killed individual P. maculata (i.e., kill rates) decreased with snail size, and kill rates on both species increased with crayfish size. Kill rates on juvenile P. maculata were higher than kill rates on size-matched hatchling P. paludosa, and crayfish fed selectively on P. maculata when offered mixed groups of size-matched snails. Further analyses revealed that hatchling P. paludosa possess shells 1.8× heavier than size-matched P. maculata suggesting differences in vulnerability to crayfish were consistent with interspecific differences in shell defenses. Differences in hatchling size and defensive traits in combination make crayfish kill rates on hatchling P. maculata approximately 15.4× faster than on hatchling P. paludosa, but the relative contribution of hatchling size to differences in apple snail vulnerability was >3× greater than the contribution of defensive traits.

In the United States, populations of nonindigenous Pomacea spp. have been reported in at least 10 states, and the rate of spread has been greatest in the southeastern United States, particularly in Florida. Factors impacting successful establishment of molluscs include salinity, pH, and desiccation tolerance. This article reports on median survival and growth of Pomacea canaliculata and Pomacea maculata (hatchlings through adults) in 28-day trials focused on these factors with an ambient condition serving as a control (e.g., 0 = salinity control). Overall hatchlings had the lowest survival, followed by juveniles then adults. Median survival was less than 28 days for all salinity treatments greater than 16. Median survival was 28 days for all pH levels (5.5–9.5) for juveniles and adults of both species. Median survival in desiccation treatments (>80% relative humidity and wet sand or

Understanding differences in behavioral characteristics between invasive non-native species and native species is an important step in preventing, managing, and mitigating environmental impacts. This study examined the differences between adult life-stage native Pomacea paludosa (Florida Applesnail) and adult non-native Pomacea maculata (Giant Applesnail) grazing behavior and rates on Vallisneria americana (Tapegrass), a plant of restoration importance, to assess the potential ecological impact. We used an experimental design with entire intact specimens of Tapegrass placed in 8 tanks of each of 3 treatment groups: (1) grazed by Giant Applesnail, (2) grazed by Florida Applesnail, and (3) control with no snails. Rates of herbivory on, and physical and total biomass damage to, Tapegrass by Giant Applesnail were 1.8 cm/hr, 2.5cm/hr, and 4.2 cm/hr, respectively. Rates of herbivory on, and physical and total biomass damage to, Tapegrass by Florida Applesnail were 0.2 cm/hr, 1.2 cm/hr, and 1.4 cm/hr, r...

The freshwater snails Pomacea Perry, 1810 lay conspicuous aerial egg clutches that are ignored by most predators. Egg biochemical defenses in the apple snail Pomacea canaliculata (Lamarck, 1822) are provided by multifunctional proteins. We analyzed the eggs of a sympatric species, Pomacea maculata Perry, 1810, studying the gross composition, toxicity, hemagglutinating activity, and its antinutritive and antidigestive properties. Eggs are mostly composed of polysaccharides (mainly galactogen) and proteins, followed by lipids and nonsoluble calcium. Two perivitellins account for ∼85% dry mass of the egg protein. The major lipids are phospholipids and sterols. A suite of potential defenses was determined, including strong lethal neurotoxicity on mice and moderate antidigestive and lectin activities. Remarkably, their polysaccharides were refractive to in vitro digestion by digestive glycosidases. This study characterized ∼99% of egg composition and identified multiple potential defenses, provided not only by proteins but also by polysaccharides. This is the first evidence to our knowledge that reserve sugars may be involved in defenses, giving further insight into the unusual reproductive strategy of these well-defended snail eggs.

Warming and eutrophication can have varying effects on exotic species performance and their interactions. These effects can vary with trophic level, but are rarely investigated simultaneously on exotic species from multiple trophic levels. To address this, we manipulated temperature, nutrients, and plant origin (native vs. exotic) in snail invaded wetland communities. Warming increased exotic apple snail (Pomacea maculata) reproduction (4-fold increase in egg mass) and also number of egg clutches produced while warming slowed exotic snail growth, suggesting a trade-off between reproduction and growth in exotic snails influenced by warming and nutrients. However, exotic snail size varied with warming and nutrients. Additionally, warming reduced native plant mass with no effect on exotic plants while nutrients had greater positive effects on exotic plants biomass. In combination warming and nutrient enrichment will likely increase exotic snail growth, while nutrient enrichment alone will contribute to exotic plant dominance. In conclusion, the individual and interactive effects of warming and eutrophication vary with the trophic level of exotic species with trade-offs in exotic herbivores depending on environmental conditions, making it difficult to predict effects of multiple anthropogenic factors on co-occurring exotic plants and their effects on native communities.

Extract from marine mollusc possess many bioactive compounds such as antimicrobes, antineoplastic, anti-inflammation and antioxidant that inhibit lipid peroxidation and act as antiradical. However, studies on freshwater snail such as apple snail are still limited and given less attention due to being label as a pest in paddy fields and wetlands. Hence, this study aims to evaluate the antioxidant activity of crude methanol and chloroform extract of apple snail, Pomacea maculata. The antioxidant activity of the extracts was determined based on DPPH radical scavenging. The results demonstrated that crude methanol extract possesses superior antioxidant activity compared to chloroform extract. Methanol extract reduces DPPH radical by 83.85 ± 2.67 % with chloroform crude extract was only 11.29 ± 3.25 %. This finding concludes that the methanol extract from P. maculata possesses a high antioxidant activity.

The rat lungworm Angiostrongylus cantonensis is a nematode parasite that can cause potentially fatal eosinophilic meningitis in humans. The life cycle of A. cantonensis involves multiple hosts, with the most common terminal hosts being rodents and intermediate hosts comprising gastropods. One such gastropod is the invasive island apple snail Pomacea maculata, which is native to South America but is currently established in several states in the USA, including South Carolina. It has been identified as an intermediate host for A. cantonensis in several locations in Louisiana. The ability of the island apple snail to serve as an intermediate host for A. cantonensis poses significant potential threats to human health, yet no studies to date have determined the prevalence of this parasite in island apple snails in South Carolina. The objective of this study was to investigate the frequency of occurrence of A. cantonensis in South Carolina island apple snails by using a real-time PCR assay. One-hundred individuals from each of three distinct stormwater retention ponds were tested, and no positive detections were found. Determining the prevalence of A. cantonensis in island apple snails is critical in accurately informing the public as to the risks involved in handling and/or consuming island apple snails.

SUMMARYRice productivity is limited by many pests, especially Pomacea spp. in Southeast Asia. Pomacea spp. damage to rice depends on sowing methods, flooded conditions, and snail densities in the field. Therefore, this study aims to evaluate the effect of different sowing methods, water levels, and snail density (1, 2, and 3 snails per plot) on the damage potential of Pomacea maculata and Pomacea canaliculata to rice and its yield. Both species caused complete loss of crop in direct seeding and 14 days old transplanted rice. The least damage by both species was recorded in 21 and 28 days old transplanted rice with no further damage after week five. Irrigation and snail density also influenced damage whereby highest damage was recorded in rice grown with 5 cm water level in comparison to 2 cm. At 2 cm water level, damage by various snail densities was trivial. However, in 5 cm water level, damage increased with the increasing snail density and the highest damage was observed at three snails per plot of either species. No difference in inflicted damage to various treatments was observed between two species, suggesting their equal damage potential on rice. Meanwhile, rice yields in 2 cm water level treatments were compatible with 5 cm control treatment. The least yield was recorded in treatments with three snails per plot of either species at 5 cm water level. Understanding the effect of sowing method and suitable water level is important as it can be further incorporated into rice cultivation practices to reduce damage of apple snails and ensure a high yield during harvest.

Novel ecosystems arise for a variety of reasons, most notably from the introduction of nonnative species. Understanding the interactions between traditional habitats, novel habitats, and species of conservation interest is important when planning successful conservation strategies. In the United States, the snail kite Rostrhamus sociabilis plumbeus is a federally endangered species whose population in Florida has undergone declines within the past decade. While studying the foraging behavior of breeding snail kites on Lake Tohopekaliga (Lake Toho), we discovered the unexpected use of disturbed ephemeral wetlands adjacent to the lake. These wetlands represent a novel habitat for snail kites; they would not have been viable foraging areas prior to the introduction of the exotic island apple snail Pomacea maculata. By examining the differences between snail kite behavior in traditional and novel habitats, we were able to identify some characteristics of novel habitats that may be important in determining their value to snail kites. The novel wetland areas were highly attractive to snail kites, likely because of the high snail capture rates. The survival of snail kite nests occurring within the novel areas appeared to be similar to that of nests occurring in more traditional, nearby areas on Lake Toho. However, whether or not snail kites used novel habitats as nesting areas appeared to be dependent upon water depth and availability of nesting substrate within these areas. The snail kites' dynamic use of the novel habitat demonstrates both the value of a novel ecosystem and the importance of traditional habitats to a species of conservation concern.

Apple snails of the genus Pomacea native to South America have invaded and become established in Europe, Asia, and the United States. Both the channeled apple snail Pomacea canaliculata and the island apple snail Pomacea maculata have been reported in theUnited States. The two species are difficult to distinguish usingmorphological characters, leading to uncertainty about the identity of the animals from populations in the United States. Because the snails are subtropical, their tolerance of low temperatures is a critical factor in limiting the spread of the animals from present localities along the coast of the Gulf ofMexico to more northern areas. The tolerance of P. maculata collected in Louisiana to temperatures as low as 0°C was examined. There was no mortality among animals maintained in water at temperatures of 20°C or 15°C for 10 days. Survival of animals during a 10-day exposure towater at temperatures 10°C and 5°C was 50%. The LD50 for a 10-day exposure was 7°C. Snails did not survivemo...

The anatomy of the gills of aquatic gastropods has not been extensively studied, and in particular, there are few recent studies that contain ultramicroscopic images. Similarly, the literature on the anatomy of the lungs of air-breathing terrestrial snails is not voluminous. Apple snails of the genus Pomacea possess both a gill and a fully functional lung. The lung is used to breathe air and as a flotation device. This study reports on the anatomy of the gill, lung, and pneumostome of the invasive species Pomacea maculata. The gill has a structure similar to that reported in other gastropods. The gill is monopectinate and consists of numerous triangular filaments. Ciliary tracts populate the distal portions of the filaments. The filaments are primarily connective tissue, interspersed with abundant muscle bands and hemolymph sinuses. The lung is a large ovoid sac; the floor is attached to the foot of the snail and the roof of the lung underlies the mantle epithelium. The lung tissue layers consist of connective tissue and smooth muscle bundles, and hemolymph spaces are present in both the floor and roof. Cells that contain calcium granules are very abundant in the lung tissue. Patches of cilia adorn the epithelium adjacent to the central airspace. The pneumostome is a muscular structure and is heavily ciliated. The lung volume of a 50-g animal is about 6 mL. The results of this study add to the knowledge of the anatomy of respiratory organs in molluscs and show that the lung is a major site of storage of calcium.

The effect of long-term estivation on the abundance of calcium granules in the lung tissue of the apple snail Pomacea maculata Perry was studied. Electron-dispersive spectrophotometric analysis of the shell and the granular inclusions in the lung show that both structures are composed of calcium carbonate. The layers forming the shell are similar to those found in the shells of other gastropods. Calcium granules are extremely abundant in the tissues of the lung of P. maculata. The spherical granules consist of concentric layers of material inside calcium cells. There are three distinct populations of hemocytes in P. maculata hemolymph, two cell types with granulocytic morphology and one agranular type. Selective staining shows that hemocytes contain large amounts of calcium, implicating these cells in the transport of calcium carbonate from storage sites to other tissues. The pCO2 of the hemolymph increases in estivating gastropods, and it has been suggested that stores of solid calcium carbonate are mobilized to buffer the resulting acidity. Results of this study show that a large decrease in the abundance of calcium carbonate granules in the lung tissue occurs during estivation. In addition, there is evidence that a calcium binding protein is present in the hemocytes.

Invasive apple snails, Pomacea canaliculata and P. maculata, have a widespread distribution globally and are regarded as devastating pests of agricultural wetlands. The two species are morphologically similar, which hinders species identification via morphological approaches and species-specific management efforts. Advances in molecular genetics may contribute effective diagnostic tools to potentially resolve morphological ambiguity. DNA barcoding has revolutionized the field of taxonomy by providing an alternative, simple approach for species discrimination, where short sections of DNA, the cytochrome c oxidase subunit I (COI) gene in particular, are used as ‘barcodes’ to delineate species boundaries. In our study, we aimed to assess the effectiveness of two mitochondrial markers, the COI and 16S ribosomal deoxyribonucleic acid (16S rDNA) markers for DNA barcoding of P. canaliculata and P. maculata. The COI and 16S rDNA sequences of 40 Pomacea specimens collected from six localities in Peninsular Malaysia were analyzed to assess their barcoding performance using phylogenetic methods and distance-based assessments. The results confirmed both markers were suitable for barcoding P. canaliculata and P. maculata. The phylogenies of the COI and 16S rDNA markers demonstrated species-specific monophyly and were largely congruent with the exception of one individual. The COI marker exhibited a larger barcoding gap (6.06–6.58%) than the 16S rDNA marker (1.54%); however, the magnitude of barcoding gap generated within the barcoding region of the 16S rDNA marker (12-fold) was bigger than the COI counterpart (approximately 9-fold). Both markers were generally successful in identifying P. canaliculata and P. maculata in the similarity-based DNA identifications. The COI + 16S rDNA concatenated dataset successfully recovered monophylies of P. canaliculata and P. maculata but concatenation did not improve individual datasets in distance-based analyses. Overall, although both markers were successful for the identification of apple snails, the COI molecular marker is a better barcoding marker and could be utilized in various population genetic studies of P. canaliculata and P. maculata.

Apple snails, in the genus Pomacea, have gained considerable notoriety for their impact on invaded habitats. Louisiana is currently under invasion by Pomacea maculata, which represents a potential threat to the state's valuable plants and cash crops. Insight into the physiology of the invasive snail may assist in developing control measures and enhance our understanding of the processes of adaptation and coevolution that accompany introductions. This paper addresses the capacity, extent, and means by which aquatic apple snails in Louisiana tolerate aerial exposure, as well as the factors that contribute to desiccation tolerance in P. maculata. Invasive P. maculata in Louisiana survived about 10 months of aestivation before 50% mortality was incurred, during which body mass was reduced by only about 30%; mortality and loss of body mass were positively correlated during aestivation. Size affects the loss of body mass in snails under 20 grams. Relative humidity interfered with the induction of aestivation, but it did not significantly affect the loss of body mass. Invasive apple snails in Louisiana also demonstrated the inclination and ability to sustain travel for at least three hours over dry land, at a rate of two meters per hour. The results of this study show that P. maculata is well adapted for survival in the absence of water. The ability to sustain travel over land and to endure long periods of aerial exposure suggests that the dry-down of infested bodies of water would not significantly impact populations of P. maculata in Louisiana.

The genus Pomacea contains most of the economically important Ampullariid apple snails. Five Pomacea species were reported introduced out of their native ranges, including three highly invasive species, i.e. P. maculata, P. canaliculata and an unidentified species, Pomacea sp. In this study, the mitogenome of P. maculata was determined, which carried typical gene set of metazoan mitogenomes and shared the same gene rearrangement of Ampullariidae mitogenomes. The control region of the P. maculata has a 13-bp inverted repeat unit. We compared the mitogenome of P. maculata with P. canaliculata, Pomacea sp. and the aquatic pet species, P. diffusa. The three highly invasive species showed high sequence similarity of PCGs and RNAs. atp8 and nad2 showed the lowest similarity and the highest Ka/Ks ratios, indicating that both genes have potential for studying species identification and populations genetics in apple snails. All PCGs have the Ka/Ks ratios

Recent studies suggest native aquatic predators can favor native over invasive species and provide biotic resistance to invasions. The invasive apple snail, Pomacea maculata continues to spread in freshwaters of Florida and appears to be a strong competitor of the native Florida apple snail (P. paludosa). Little is known about effects of predators on either species and we compared the effects of a common native crayfish predator (Procambarus fallax) on hatchlings and juveniles. Because crayfish feed size-selectively, we predicted that the smaller P. maculata hatchlings would be more vulnerable than the hatchlings of native P. paludosa. In experimental wetland mesocosms, crayfish reduced survival of both species, but none of the P. maculata survived the 44 days exposure, such that predatory effects of crayfish were >8× stronger on the non-native P. maculata than on native P. paludosa. Crayfish in the lab selectively consumed the smaller P. maculata when offered both hatchlings simultaneously. We combined the observed survival rates with published life history data and the results (i.e., projected survivors clutch−1) suggested that wetlands with crayfish could have greater limiting effects on non-native P. maculata than the native P. paludosa. Wetland conditions favoring populations of native crayfish may also favor the relatively predator-resistant native P. paludosa.

The invasive Pomacea maculata (= Pomacea insularum) (Perry) (Island Apple Snail) is becoming increasingly abundant in the southeastern US with potentially detrimental effects on wetland vegetation and water quality. Here, we investigate the association of plant-community structure and aquatic-predator abundance with Island Apple Snail invasion in seasonal wetlands on a cattle ranch in south-central Florida. We found a negative correlation between Island Apple Snail abundance and abundance of its preferred forage species, raising concerns that the snail may have already altered plant communities in these seasonal wetlands. We also found a negative correlation between Island Apple Snail abundance in wetlands and distance to the nearest ditch. In a snail-growth experiment, we found a negative effect of species evenness and a positive effect of total vegetation cover on Island Apple Snail weight gain. To understand Island Apple Snail invasion success in seasonal wetlands, more research is needed on t...

Summary Ecosystems with multiple exotic species may be affected by facilitative invader interactions, which could lead to additional invasions (invasional meltdown hypothesis). Experiments show that one-way facilitation favours exotic species and observational studies suggest that reciprocal facilitation among exotic species may lead to an invasional meltdown. We conducted a mesocosm experiment to determine whether reciprocal facilitation occurs in wetland communities. We established communities with native wetland plants and aquatic snails. Communities were assigned to treatments: control (only natives), exotic snail (Pomacea maculata) invasion, exotic plant (Alternanthera philoxeroides) invasion, sequential invasion (snails then plants or plants then snails) or simultaneous invasion (snails and plants). Pomacea maculata preferentially consumed native plants, so A. philoxeroides comprised a larger percentage of plant mass and native plant mass was lowest in sequential (snail then plant) invasion treatments. Even though P. maculata may indirectly facilitate A. philoxeroides, A. philoxeroides did not reciprocally facilitate P. maculata. Rather, ecosystems invaded by multiple exotic species may be affected by one-way facilitation or reflect exotic species’ common responses to abiotic factors or common paths of introduction.

Apple snails (Ampullariidae) are among the largest and most ecologically important freshwater snails. The introduction of multiple species has reinvigorated the field and spurred a burgeoning body of research since the early 1990s, particularly regarding two species introduced to Asian wetlands and elsewhere, where they have become serious agricultural pests. This review places these recent advances in the context of previous work, across diverse fields ranging from phylogenetics and biogeography through ecology and developmental biology, and the more applied areas of environmental health and human disease. The review does not deal with the role of ampullariids as pests, nor their control and management, as this has been substantially reviewed elsewhere. Despite this large and diverse body of research, significant gaps in knowledge of these important snails remain, particularly in a comparative framework. The great majority of the work to date concerns a single species, Pomacea canaliculata, which we see as having the potential to become a model organism in a wide range of fields. However additional comparative data are essential for understanding this diverse and potentially informative group. With the rapid advances in genomic technologies, many questions, seemingly intractable two decades ago, can be addressed, and ampullariids will provide valuable insights to our understanding across diverse fields in integrative biology. Fil: Hayes, Kenneth A.. Howard University; Estados Unidos. University Of Hawaii At Manoa; Estados Unidos. National Museum of Natural History; Estados Unidos Fil: Burks, Romi L.. Southwestern University; Estados Unidos Fil: Castro Vazquez, Alfredo Juan. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Darby, Philip C.. University of West Florida; Estados Unidos Fil: Heras, Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina Fil: Martín, Pablo Rafael. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Qiu, Jian wen. Hong Kong Baptist University; Hong Kong Fil: Thiengo, Silvana C.. Instituto Oswaldo Cruz; Brasil Fil: Vega, Israel Aníbal. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Wada, Takashi. Kyushu Okinawa Agricultural Research Center; Japón Fil: Yusa, Yoichi. Nara Women’s University; Japón Fil: Burela, Silvana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Cadierno, María Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina Fil: Cueto, Juan Agustin. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Dell Agnola, Federico Agustín. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Dreon, Marcos Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Frassa, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina Fil: Giraud Billoud, Maximiliano German. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Godoy, Martín Sergio. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Ituarte, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina Fil: Koch, Eduardo. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Matsukura, Keiichiro. University Of Hawaii At Manoa; Estados Unidos Fil: Pasquevich, María Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Bioquímicas de La Plata; Argentina Fil: Rodríguez, Cristian. Consejo Nacional de Investigaciones Cientií­ficas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina Fil: Saveanu, Lucía. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Seuffert, Maria Emilia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Strong, Ellen E.. National Museum of Natural History; Estados Unidos Fil: Sun, Jin. Hong Kong Baptist University; Hong Kong Fil: Tamburi, Nicolas Eduardo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Tiecher, María José. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina Fil: Turner, Richard. Florida Institute of Technology; Estados Unidos Fil: Valentine Darby, Patricia L.. The Pomacea Project, Inc.; Estados Unidos Fil: Cowie, Robert H.. University Of Hawaii At Manoa; Estados Unidos

Plants have evolved sophisticated embryo defences by kinetically-stable non-digestible storage proteins that lower the nutritional value of seeds, a strategy that have not been reported in animals. To further understand antinutritive defences in animals, we analysed PmPV1, massively accumulated in the eggs of the gastropod Pomacea maculata, focusing on how its structure and structural stability features affected its capacity to withstand passage through predator guts. The native protein withstands >50 min boiling and resists the denaturing detergent sodium dodecyl sulphate (SDS), indicating an unusually high structural stability (i.e., kinetic stability). PmPV1 is highly resistant to in vitro proteinase digestion and displays structural stability between pH 2.0–12.0 and 25–85 °C. Furthermore, PmPV1 withstands in vitro and mice digestion and is recovered unchanged in faeces, supporting an antinutritive defensive function. Subunit sequence similarities suggest a common origin and tolerance to mutations. This is the first known animal genus that, like plant seeds, lowers the nutritional value of eggs by kinetically-stable non-digestible storage proteins that survive the gut of predators unaffected. The selective pressure of the harsh gastrointestinal environment would have favoured their appearance, extending by convergent evolution the presence of plant-like hyperstable antinutritive proteins to unattended reproductive stages in animals., Facultad de Ciencias Médicas

Pomacea maculata is a relatively new invasive species to the Gulf Coast region and potentially threatens local agriculture (rice) and ecosystems (aquatic vegetation). The population dynamics of P. maculata have largely been unquantified, and therefore, scientists and field-workers are ill-equipped to accurately project population sizes and the resulting impact of this species. We studied the growth of P. maculata ranging in weights from 6 to 105 g, identifying the sex of the animals when possible. Our studied population had a 4:9 male:female sex ratio. We present the findings from initial analysis of the individual growth data of males and females, from which it was apparent that females were generally larger than males and that small snails grew faster than larger snails. Since efforts to characterize the male and female growth rates from individual data do not yield statistically supported estimates, we present the estimation of several parameterized growth rate functions within a population-level mathematical model. We provide a comparison of the results using these various growth functions and discuss which best characterizes the dynamics of our observed population. We conclude that both males and females exhibit biphasic growth rates, and thus, their growth is size-dependent. Further, our results suggest that there are notable differences between males and females that are important to take into consideration in order to accurately model this species' population dynamics. Lastly, we include preliminary analyses of ongoing experiments to provide initial estimates of growth in the earliest life stages (hatchling to ≈6 g).

We used camera traps to determine which predators were responsible for depredated Pomacea maculata (Maculata Apple Snail) shells at 2 different study sites. Evidence of predation at these sites included operculums near the shells with a small amount of flesh attached and shells accumulating a meter or more from the water's edge with no evidence of recent flooding. In both locations, the most frequently observed potential predators were Procyon lotor (Raccoon), which was the only species directly observed capturing and eating Apple Snails.

One of the most successful groups of invasive consumers worldwide is freshwater snails of the family Ampullariidae, including Pomacea maculata, yet little is known about snail survival and growth in the range of conditions found in estuarine ecosystems. Here, we provide an experimental assessment of P. maculata survivability in estuarine conditions, documenting: (1) egg susceptibility to tidal inundation (2) salinity tolerance of snails, and (3) salinity effects on hatchling growth. Results indicate that estuarine conditions will not limit apple snail colonization in oligohaline and mesohaline reaches of estuaries, with eggs remaining viable when exposed to periodic inundations typical of a tidal regime and modest, albeit reduced, growth and survival at moderate salinities (5 and 10 ppt). For this reason, rapid detection and eradication of P. maculata in estuarine areas is needed to avoid the invasion of snails in these vital, productive environments.

Aim: This study aims to understand the distribution of Pomacea spp. in various rice fields of Peninsular Malaysia. Place and Duration of study: The study was conducted at twenty five rice fields from five states in Peninsular Malaysia (Selangor, Perak, Penang, Kedah and Kelantan) during the sowing and harvesting of off rice season-2013. Methodology: This study was carried out on rice fields of one acre in size which were further divided into four blocks. A 0.5m quadrate was used for sampling and snails within the quadrate were collected, counted and identified based on their shell morphology by the experts. Results: Based on this study, Pomacea maculata was more abundant and widely distributed as compared to Pomacea canaliculata. Rice fields in Perak showed the highest population distribution of Pomacea spp. during both sowing and harvesting of rice. Original Research Article Annual Research & Review in Biology, 4(24): 4123-4136, 2014 4124 Meanwhile, the lowest population was observed in rice fields during the sowing of rice in Kelantan and during harvesting of rice in Kedah. Comparatively higher population of Pomacea spp. was recorded during sowing of rice than harvesting. No population of P. canaliculata was observed from the rice fields of Penang state. Water temperature, pH and the number of rice seedlings does not have a significant effect on the distribution of Pomacea spp. Conclusion: The results from this study could help in an area wide management program against Pomacea spp., not only to minimize their damage to rice but also to control their further spread.

Pomacea maculata is a freshwater snail native to various regions of South America. In the 1990's invasive populations of P. maculata began to establish in Texas, Florida, and Georgia. These snails have a high fecundity rate and feed on macrophytes. Water bodies in southern Florida undergo frequent fluctuations in water levels; most are controlled by pumps, culverts, gates and levees. A proposed control method for these snails is the inundation of the egg clutches. This study compared the hatching success of unsubmerged egg clutches with the hatching success of partially submerged egg clutches, the growth rates of snails hatched in the treatments, and determined if snails hatched in submerged conditions are viable to a shell length that exceeds 25 mm, a size typically capable of reproduction. Hatchling success was not significantly different amongst treatments; likewise, growth rates were similar despite inundation. Pomacea maculata egg clutches submerged at various times during their incubation can become detached from the vegetation and sink or float. Floating egg clutches can be transported through water control structures and canals, thus facilitating the spread to non-impacted areas. Manual methods for removal of egg clutches and adults may prove more effective in control efforts.

At least 14 species of apple snail (Ampullariidae) have been released to water bodies outside their native ranges; however, less than half of these species have become widespread or caused appreciable impacts. We review evidence for the impact of apple snails on natural and managed wetlands focusing on those studies that have elucidated impact mechanisms. Significant changes in wetland ecosystems have been noted in regions where the snails are established: Two species in particular (Pomacea canaliculata and Pomacea maculata) have become major pests of aquatic crops, including rice, and caused enormous increases in molluscicide use. Invasive apple snails have also altered macrophyte community structure innatural and managed wetlands through selective herbivory and certain apple snail species can potentially shift the balance of freshwater ecosystems from clear water (macrophyte dominated) to turbid (plankton dominated) states by depleting densities of native aquatic plants. Furthermore, the introductions of some apple snail species have altered benthic community structure either directly, through predation, or indirectly, through exploitation competition or as a result of management actions. To date much of the evidence for these impacts has been based on correlations, with few manipulative field or mesocosm experiments. Greater attention to impact monitoring is required, and, for Asia in particular, a landscape approach to impact management that includes both natural and managed-rice wetlands is recommended. © 2012 Elsevier Masson SAS.

The spread of non-native species raises concerns about native species displacement, while other negative effects on native species (e.g., habitat degradation) should also be considered. The highly invasive non-native apple snail Pomacea maculata has raised such concerns as it has become established in a wide range of aquatic systems worldwide. While monitoring native Florida P. paludosa populations in Lake Tohopekaliga (LTOHO) from 2001 to 2009 and in Water Conservation Area 3A (WCA3A, Everglades) from 2006 to 2015, we opportunistically documented the establishment and distribution of P. maculata. We estimated snail densities and recorded egg cluster presence in three study sites (12 total plots, LTOHO) and 137 sites (WCA3). On LTOHO, native snails were absent or at very low densities prior to finding P. maculata. Few snails of either species were found in high-stem-density vegetation of the littoral zone. Pomacea maculata immigration into the littoral zone occurred following managed vegetation removal, and Hydrilla verticillata proliferation in LTOHO likely contributed to the spread of P. maculata. We found both native and non-native apple snail species in many WCA3A sites following P. maculata invasion. We initially found the non-native snail in two sites in southern WCA3A; they were mostly restricted to within three kilometers of initial sites over the next four years. Overall plant community compositions in LTOHO and WCA3A appeared less impacted than expected based on previous reports of P. maculata invasions.

Louisiana's wetlands and crops are presently under invasion by Pomacea maculata (Perry, 1810). Insight into the physiology of ampullariids is vital to informing threat assessment, developing effective control measures, and enhancing our understanding of the physiological adaptations that facilitate successful introductions of invasive species. This paper addresses the respiratory physiology and heart rate of P. maculata submersed in water, during initial and extended (aestivation) emersion in air. Invasive P. maculata in Louisiana possess fully functional lungs and gills, permitting survival in air without access to water, and reciprocally, survival in water with no access to air. The aquatic respiration rate measured as V O2 (∼19 µL/g/h) was significantly lower than the initial aerial respiration rate (∼ 63 µL/g/h) for P. maculata, while the heart rate was similar in both water (∼37 bpm) and during initial emersion in air (∼34 bpm). Small snails ( 60 g) snails. A substantial reduction in heart rate (86%), body weight (24%), and V 02 (94%) was observed in P. maculata after 58 days of aestivation in air. Periodic changes in the rate of oxygen uptake and cardiac arrhythmia were regularly observed in snails during emersion in air.

Background: Synthetic molluscicides are routinely used in the control of apple snails (Pomacea spp of Ampullariidae family), the invasive rice pest. Molluscicidal bait is a strategic combination of food and toxicant to attract the target pests. However, baits are found to be feed deterrent due to snails' own feed preferences in a paddy field. There is no specific feed formulation exclusively developed as the base carrier material for the development of molluscicidal bait for the apple snail (Pomacea maculata Perry). Further, there are limitations in evaluating the efficacy of a snail feed/bait formulation based on its attractiveness, palatability, and directional movement of snails with the existing experimental devices. Therefore, this study was aimed to develop an attractive and appetent feed formulation as a bait carrier material and also to design and develop a snail attractant tracking device (SATD) for evaluating the feed formulation precisely. Materials and Methods: Snails were collected from the snail-infested rice field located in Kedah, Malaysia. A glass aquarium tank of size 60 cm × 30 cm × 30 cm was physically partitioned to form four linear channels (tracks) using 5-mm thickness transparent perflex plastic sheets to develop SATD and snail feed formulations were evaluated with the help of it. Results: This study resulted in the development and evaluation of attractant feed formulations prepared with a combination of different types of carbohydrates and protein hydrolysates. Analysis of variance showed significant differences (P

A survey for freshwater gastropods carrying trematodes parasites was conducted in Manso Dam and the surrounding areas frequented by tourist, focusing particularly on the Pantanal region. Infected snails were recovered from twelve of the eighteen investigated municipalities and forty-one cercaria-snail pairings were recorded. Among these pairings were several first records of snails serving as intermediate hosts for trematodes in Brazil including Biomphalaria amazônica Paraense, 1966, Biomphalaria occidentalis Paraense, 1981, Marisa planogyra Pilsbry, 1933, Pomacea maculata Perry, 1830, Pomacea scalaris (d'Orbigny, 1835) and Gundlachia radiata (Guilding, 1828). Echinostomatidae and Strigeidae were the most common trematode families (ca. 47%) and the greatest diversity of larvae were obtained from Drepanotrema lucidum (Pfeiffer, 1839). Paramphistomatidae, Schistosomatidae or Spirorchiidae and Notocotylidae or Pronocephalidae were recovered in D. lucidum for the first time extending the number of families which use this gastropod as intermediate host. Although no specimens were found harboring larval stages of Schistosoma mansoni Sambon, 1907 other trematode larvae were discovered, including the Schistosomatidae Brevifurcate apharingeate cercaria that can cause dermatitis in humans. Continued studies on the taxonomy and biology of trematodes are essential to better understand the biodiversity of these parasites as well as the epidemiological aspects for control of associated zoonosis.

Two species of apple snails, Pomacea canaliculata and Pomacea maculata (formerly Pomacea insularum), have invaded many countries of East and Southeast Asia from their native range in South America. This study investigated the genetic structure of the two species invading these areas. Phylogenetic analysis based on sequences of the nuclear gene elongation factor 1-alpha (EF1α) detected two well-supported clades (Clade C and Clade M). Both P. canaliculata and P. maculata were represented in each clade. Some snails had both Clade C and Clade M EF1α sequences. These results suggest genetic exchange between snails of the two clades. A mating experiment between P. canaliculata with Clade C EF1α sequences and P. maculata with Clade M EF1α sequences resulted in viable F1 progeny under laboratory conditions. The genetic exchange was also inferred in some populations collected from Argentina, suggesting an existence of hybrid in the native range. Simple identification of EF1α types using a restriction enzyme, ApaLI, detected significant geographical structure of the EF1α variants in the invaded area. The divergent geographical structure could have resulted from either the founder effect or the bridgehead effect, although further genetic analysis is needed to clarify this. Average individual egg weight, which is an indicator of egg size, was higher in P. canaliculata than P. maculata in both field and laboratory reared samples, suggesting that some (probably most) P. canaliculata and P. maculata invading East and Southeast Asia still maintain species-specific populations.