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Lymnaea acuminata (Pulmonata: Lymnaeidae) is a generalist species with a wide Palaearctic distribution throughout Europe, Asia, and the Far East including Siberia. It is common in shallow water bodies such as ponds, swamps, and floodplains of rivers, which are relatively unstable habitats and show large fluctuations in temperature and water level and occasional desiccation. Phenotypic and genotypic differentiation in pond snail, Lymnaea acuminata, was studied by morphometric and RAPD analysis in Jammu region. Morphometric studies indicated that the shell shapes of the subtropical populations of L. acuminata were highly differentiated from intermediate and temperate populations. Elongated shells with narrow apertures are present under subtropical conditions, while a more compact shell shape with a wider aperture was present in intermediate and temperate conditions. To understand the genetic cause of two morphs of pond snail among populations, RAPD-PCR analysis was done. The RAPD data showed close linkage between the populations of subtropics, intermediate, and temperate habitats. The high pair-wise similarity and low-distance matrix suggest a limited genetic variation. Examination of genetic relatedness between populations, as determined by RAPD-PCR analysis, revealed that the subtropical, intermediate, and temperate populations appeared to share a common ancestry, and the difference in their shell morphology was attributed to phenotypic plasticity.

Objectives: Two freshwater snails Bellamya bengalensis and Lymnaea acuminata from Malangaon reservoir of Dhule district (Maharashtra, India) were examined to study biomarkers of oxidative stress with the investigation of antioxidant enzyme activities. Methods: The experimental snail species were collected seasonally and acclimatized in the laboratory. Their digestive glands were used to study the activities of oxidative biomarker enzymes like Lipid PerOxidation (LPO), Glutathione-S-Transferase (GST), reduced glutathione (GSH), SuperOxide Dismutase (SOD), CATalase (CAT) and Glutathione Peroxidase (GPx). All investigations were carried out on double beam spectrophotometer (Elico BL 200). Findings: It was observed that, LPO level in B. bengalensis was 0.63, 0.55and 0.60(nmol of MDA formed/mg protein) while in L.acuminata 0.74, 0.67 and 0.70 respectively in summer, monsoon and winter seasons. GST activity was 23.41,15.73 and 19.61 in B. engalensis while 26.29, 18.34 and 22.29 in L.acuminata. Level of GSH was 0.083, 0.117and 0.094 (μM/g wet tissue) in B. bengalensis while in L.acuminata it was 0.018, 0.056 and 0.026 (μM/g wet tissue) in three seasons. The level of SOD was 20.87, 24.83 and 23.33 (U/mg of protein) in B. bengalensis while in L. acuminata it was 18.32, 22.35 and 20.73 in three seasons. Level of CAT was 9.23, 13.20, and 11.56 (U/mg of protein) in B. bengalensis while in L.acuminata it was 7.02, 10.53 and 8.86 (U/mg of protein) respectively during three seasons. GPx movement was 6.57, 8.50 and 7.48 (mg of GSH utilized/min/mg protein) in B. bengalensis. It was 5.05, 8.07 and 7.04 (mg of GSH utilized/min/mg protein) in L.acuminata respectively in three seasons. The obtained data also showed the lowest levels of LPO and activities of GST and uppermost doings of SOD, CAT, and GPx and uppermost heights of GSH in two snail types in rainy period than summer and winter period. This designates that in summer, the snails were under more conservation stress than winter and rainy periods. Application: It was decided that changes in antioxidant enzymes and LPO and GST activity can be used as tool in ecological nursing packages.

Objective: To evaluate the effect of enzymatic activity in the nervous tissue of snail Lymnaea acuminata (L. acuminata) by Bauhinia variegata (B. variegata) and Mimusops elengi (M. elengi) and their active molluscicidal components quercetin and saponin. Methods: Treatment of sublethal concentration (40% and 80% of 96-h LC50) in vivo of column-purified fraction of B. variegata leaf and M. elengi bark and their molluscicidal agents quercetin and saponin inhibit the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP and ALP) activities in the nervous tissue of L. acuminata. Results: AChE activity was more inhibited than ACP and ALP in snail exposed to column- purified fraction of M. elengi bark and saponin. Among all the treatments the highest inhibition in AChE activity (27.77% ) was noted in snail L. acuminata exposed to 80% of 96-h LC50 of saponin at 96-h exposure period. Conclusions: It can be concluded from the present study that inhibition of AChE, ACP and ALP by B. variegata leaf (quercetin) and M. elengi bark (saponin) in snail L. acuminata could be the cause of snail mortality.

The effect of sub-lethal doses (40% and 80% of LC50/24h) of plant derived molluscicides of singly, binary (1:1) and tertiary (1:1:1) combinations of the Rutin, Ellagic acid, Betulin and taraxerol with J. gossypifolia latex, leaf and stem bark powder extracts and their active component on the reproduction of freshwater snail Lymnaea acuminata have been studied. It was observed that the J. gossypifolia latex, stem bark, individual leaf and their combinations with other plant derived active molluscicidal components caused a significant reduction in fecundity, hatchability and survival of young snails. It is believed that sub-lethal exposure of these molluscicides on snail reproduction is a complex process involving more than one factor in reducing the reproductive capacity. O efeito de doses sub-letais (40% e 80% de LC50/24h) de moluscicidas derivados de plantas com combinações unitárias, binárias (1:1) e terciárias (1:1:1) de Rutin, ácido Elágico, Betulin e taraxerol com látex da J. gossypifolia, folhas e extrato em pó de casca de caule e seus componentes ativos foram estudados na reprodução do caramujo de água fresca Lymnaea acuminata. Foi observado que o látex da J. gossypifolia, casca do caule, folhas individualmente e suas combinações com componentes moluscicidas ativos derivados de outras plantas causaram redução significante na fecundidade, incubação e sobrevivência dos caramujos jovens. Acredita-se que a exposição sub-letal destes moluscicidas sobre a reprodução dos caramujos é processo complexo envolvendo mais de um fator na redução da capacidade reprodutiva.

Fasciolosis is a parasitic disease caused by Fasciola gigantica. The freshwater snail Lymnaea acuminata is the intermediate host of F. gigantica which cause endemic fasciolosis in the northern part of India. To investigate larvicidal activity of pure and laboratory extracted pheophorbide a (Pa) against cercaria larvae of F. gigantica, data were analyzed in different spectra of visible light, sunlight, and laboratory conditions. Photostimulation of chlorophyll derivative pheophorbide a (Pa) caused time and concentration dependent larvicidal activity against cercaria larvae of F. gigantica. Larvicidal activity of pure Pa under 650 nm and 400–650 nm (8 h LC50 0.006 mg/10 mL) was more pronounced than extracted Pa under same irradiations (650 nm LC50 0.12 mg/10 mL, 400–650 nm LC50 0.14 mg/10 mL). Lowest toxicity of pure (8 h LC50 0.14 mg/10 mL) and extracted Pa (8 h LC50 1.25 mg/10 mL) was noted under 400 nm. Pa was found to be toxic in laboratory conditions also. The results presented in this paper indicate that pheophorbide a possess potential larvicidal activity against Fasciola gigantica larvae in different wavelengths of visible light, sunlight, and laboratory conditions.

Fasciolosis is water and food borne disease, caused byFasciola hepaticaandF. gigantica. SnailLymnaea acuminatais an intermediate host of these flukes. Snail control is one of the major methods to reduce the incidences of fasciolosis. Trapping of snails with the help of photo- and chemoattractants for treatment purposes will be a new tool in control program of fasciolosis. The present study shows that maximum numbers of snails were attracted (52 to 60%), when exposed to photo- and chemostimulant simultaneously, rather than when only chemo- (control) (18 to 24%) or photo- (control) (14 to 19%) stimulus was given. Maximum change in AChE activity in nervous tissue was observed when red monochromatic light was used (258.37% of white light control) as opposed to blue (243.44% of white light control) and orange (230.37% of white light control). The exposure of light directly stimulated the photoreceptors in eye which transmit the signals through nerves to the brain and snail response accordingly. In this signal transmission AChE is one of the important enzymes involved in this process.

Fascioliasis, a snail-borne parasitic zoonosis, has been recognized for a long time because of its major veterinary and human impact. Different Bait formulations were fed to the snail Lymnaea acuminata in clear glass aquaria having diameter of 30 cm. Snail attractant containing bait formulations was prepared from different binary combination (1 : 1 ratio) of carbohydrates (glucose, starch 10 mM) and amino acid (methionine, histidine 10 mM) in 100 ml of 2% agar solution + sublethal (20% and 60% of 24 h and 96 h LC50) doses of different molluscicides (eugenol, ferulic acid, umbelliferone, and limonene). Snails fed on bait containing sub-lethal concentration of different molluscicides and the snail attractant, causing a significant inhibition in alkaline phosphatase (ALP) and acetylcholinesterase (AChE) activity in the nervous tissue of the vector snail L. acuminata. Maximum inhibition in ALP (20% of control) and AChE (49.49% of control) activity was observed in the nervous tissue of the L. acuminata exposed to 60% of 96 h LC50 of eugenol in the bait pellets containing starch + histidine, starch + methionine, respectively.

Snail Lymnaea acuminata is the intermediate host of liver fluke Fasciola gigantica, which cause endemic fasciolosis among cattle population of eastern Uttar Pradesh. Control of snail population by molluscicides is one of the effective methods to control fasciolosis. In the present study molluscicidal activity of tertiary combination of freeze-dried urine of different Indian breeds of cow Sahiwal, Geer and Tharparkar with Annona squamosa seed powder, Ferula asafoetida root latex, Azadirachta indica oil and Camellia sinensis leaves have been tested against Lymnaea acuminata. It was noted that the toxicity of tertiary combination (1:1:5) of cow urine kept for 15 days in sunlight or laboratory condition with different plant products were highly toxic against snail L. acuminata. 96 h LC50 of tertiary combinations with Sahiwal urine kept for 15 days in sunlight with A. squamosa, F. asafoetida, A. indica oil and C. sinensis were 35.47 mg L(-1), 37.13 mg L(-1), 33.66 mg L(-1), respectively higher than the Geer and Tharparkar. The toxicity of Sahiwal urine kept for 15 days in laboratory condition with A. squamosa and C. sinensis (96 h LC50 28.28 mg L(-1)) was more potent than the all other combinations. Cow urine in combination with plant product can be used for effective control of snail.

Every month during the year 2010–2011, the 24 to 96 h LC50 values of molluscicide eugenol, in snail attractant pellets (SAP), were determined against a snail Lymnaea acuminata, with concomitant determination of levels of temperature, pH, dissolved oxygen, carbon dioxide, and electrical conductivity in test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values 2.55, 2.68, and 2.91% in SAP containing starch+eugenol and 2.67, 2.54, and 2.85% in SAP containing proline+eugenol during May, June, and July, respectively, were most effective treatments in killing the snails, while SAP containing starch or proline+eugenol were least effective in January when the 24 h LC50 was 10.73% and 7.14% for starch and proline, respectively. There was a significant positive correlation between LC50 of eugenol containing SAP and levels of dissolved O2 and pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2 and temperature of test water in...

Lymnaeid snails transmit medical and veterinary trematodiases, mainly fascioliasis. Vector specificity of fasciolid parasites defines disease distribution and characteristics. Control of fascioliasis is to de-link the life cycle of fluke, by destroying the Lymnaeid snails. Different Bait formulations were fed to snail Lymnaea acuminata in clear glass aquaria having diameter of 30 cm. Snail attractant containing bait formulations were prepared from different binary combination of amino acid (valine, aspartic acid, lysine and alanine 10 mM) in 100 ml of 2% agar solution + sub-lethal (20% and 60% of 24h LC50 and 96h LC50) doses of different molluscicides (eugenol, ferulic acid, umbelliferone, and limonene). Snails were fed bait with sub-lethal concentration of different molluscicides inside the snail attractant pellets, which caused a significant inhibition in alkaline phosphatase (ALP) and acetylcholinesterase (AChE) activity in the nervous tissue of the vector snail L. acuminata. Combination of different amino acids such as valine + aspartic acid, lysine + valine, lysine + alanine and alanine + valine was used as attractant with active molluscicidal components. Maximum inhibition in ALP (23.57% of control) and AChE (49.48% of control) activity were observed in the nervous tissue of the L. acuminata exposed to 60% of 96h LC50 of ferulic acid, umbelliferone, respectively in the bait pellets containing valine + aspartic acid as attractant.

A atividade moluscicida das folhas da Bauhinia variegata e da casca do Mimusops elengi foi testada contra o vetor caracol, Limnaea acuminata. A toxicidade de ambas as plantas é dependente do tempo e da concentração. Entre os extratos orgânicos, os extratos de etanol de ambas as plantas foi mais tóxico. A toxicidade do extrato etanólico da folha da B. variegata (96 h LC50 - 14,4 mg/L) foi mais pronunciada do que o extrato etanólico da casca do M. elengi (96h - LC50 - 15,0 mg/L). As frações purificadas em coluna durante 24 h LC50 do B. variegata e da casca do M. elengi foram 20,3 mg/L e 18,3 mg/L, respectivamente. A saponina e a quercentina foram caracterizadas e identificadas como os componentes ativos moluscicidas. A co-migração da saponina (Rf 0,48) e da quercentina (Rf 0,52) com a casca purificada por coluna do M. elengi e as folhas da B. variegata na cromatografia demonstraram o mesmo valor Rf isto é, 0,48 e 0,52 respectivamente. O presente estudo indica claramente a possibilidade de usar M. elengi e/ou B. variegata como moluscicidas potentes. The molluscicidal activity of Bauhinia variegata leaf and Mimusops elengi bark was studied against vector snail Lymnaea acuminata. The toxicity of both plants was time and concentration-dependent. Among organic extracts, ethanol extracts of both plants were more toxic. Toxicity of B. variegata leaf ethanolic extract (96h LC50- 14.4 mg/L) was more pronounced than M. elengi bark ethanolic extract (96h LC50-15.0 mg/L). The 24h LC50 of column purified fraction of B. variegata and M. elengi bark were 20.3 mg/L and 18.3 mg/L, respectively. Saponin and quercetin were characterized and identified as active molluscicidal component. Co-migration of saponin (Rf 0.48) and quercetin (Rf 0.52) with column purified bark of M. elengi and leaf of B. variegata on thin layer chromatography demonstrate same Rf value i.e. 0.48 and 0.52, respectively. The present study clearly indicates the possibility of using M. elengi and/or B. variegata as potent molluscicide.

Comparative histopathological effects were observed on the digestive glands (hepatopancreas) of freshwater snail species, Vivipara bengalensis and Lymnaea acuminata infected with single (furcocercous cercariae) and double infection of digenean trematode larvae (gymnocephalous cercariae + metacercariae), respectively. Digestive glands of both the snail species revealed degenerative changes in their digestive gland tubules. The latter became irregular in shape, reduced in size with enlarged lumen and inter-tubular space besides rupturing of digestive tubules. These changes were correlated with the size and types of trematode larvae, single or double infection and degree of parasitemia. Autolytic necrosis of numerous tubules was found in digestive glands infected with double and very severe single infection. None of the tubules was found to be invaded by sporocyst, redia and cercaria. However, metacercariae were seen to invade digestive tubules of Lymnaea species.

Os efeitos tóxicos das combinações binárias e terciárias do pó de látex da Euphorbia hirta Linn assim como outros compostos vegetais moluscicidas foram avaliados em sua ação sobre caramujos de água doce Lymnaea (Radix) acuminata e Indoplanorbis exustus em represas. Estas combinações mostraram significante efeito dose e tempo dependente contra ambos os caramujos. Estes compostos em doses altas foram também letais para peixes de água doce Channa punctatus (Bloch) (Channidae {Ophicephalidae}), que compartilham o ambiente com estes caramujos mas a dose LC90 (24h) para caramujos aparentemente não tem propriedade de matar as populações de peixes quando uma população mista de peixes e caramujos são tratadas. The toxic effect of binary and tertiary combinations of Euphorbia hirta Linn latex powder with other plant molluscicidal compounds, were evaluated against the freshwater snails Lymnaea (Radix) acuminata and Indoplanorbis exustus in pond. These combinations showed significant time and dose dependent effect against both the snails. These compounds at higher doses were also lethal to freshwater fish Channa punctatus (Bloch) (Channidae {Ophicephalidae}), which shares the habitat with these snails, but the LC90 (24h) doses of snails have no apparent killing properties in fish populations when treated in mixed population of snails and fish.

Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host ofFasciolaspecies. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail orFasciolalarva redia and cercaria in the snail body.In vivoandin vitrotoxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva ofFasciolain infected snailLymnaea acuminatawere tested. Mortality of larvae were observed at 2 h, 4 h, 6 h, and 8 h, of treatment. Inin vivotreatment, azadirachtin caused highest mortality in redia and cercaria larva (8 h, LC500.11, and 0.05 mg/L) whereas inin vitrocondition allicin was highly toxic against redia and cercaria (8 h, LC500.01, and 0.009 mg/L). Toxicity of citral was lowest against redia and cercaria larva.

Sublethal treatment (20% and 60% of 24 hr LC50) of young snails (Lymnaea acuminata) with the active molluscicidal constituents ferulic acid and umbelliferone from Ferula asafoetida, eugenol from Syzygium aromaticum, and limonene from Carum carvi caused a significant reduction in the fecundity, hatchability, and survival of the snails. Treatment with the constituents also increased the length of time to hatching of snails. Withdrawal of the snails from constituent treatments after 96 hr with movement to fresh water enabled a significant reproductive recovery in the snail. A 24 hr sublethal treatment with the ferulic acid, umbelliferone, eugenol, and limonene caused a significant (p < 0.05) reduction in protein, amino acid, DNA, and RNA levels in the ovotestis of treated snails.

Earlier it has been observed that oleoresin of Zingiber officinale is a potent molluscicide ag- ainst Lymnaea acuminata. This snail is the vector of Fasciola species, which cause ende- mic fascioliasis in eastern Uttar Pradesh. As this snail breeds and maintain their population constant through out the year, so that the present study has been designed to find out the effect of variations in some environmental factors in different seasons, on the molluscicidal activity of oleoresin of Zingiber officinale and its relative effect on certain enzymes viz., acetylcholinesterase, acid and alkaline phosphatases in the nervous tissue of the snail Lymnaea acuminata. In this study temperature, pH, dissolve oxygen, free carbon dioxide, conductivity of the water in control, as well as molluscicide treated water, was measured simultaneously. LC50 value of oleoresin was determined in each month of the year. Toxicity of oleoresin in June-July (24 h LC50 16.54-14.28 mgL-1) is highest. Acetylcholinesterase, acid and alkaline phosphatases activity in the nervous tissue of the snails treated with sub-lethal concentration of oleoresin was simultaneously measured. Sig- nificant positive rank correlation, in between the acetylcholinesterase or acid phosphatase activity and LC50 of oleoresin was observed. The pre- sent study conclusively shows that variant abi- otic factors can significantly alter the toxicity of oleoresin of Z. officinale in L. acuminata. The most suitable period for control of L. acuminata is June-July.

The molluscicidal activity of powdered nutmeg and mace (Myristica fragrans Houtt.) against the vector snail Lymnaea acuminata was evaluated. The toxicity of both the spices was time- and dose-dependent. The toxicity of mace powder (96 h LC50 = 28.61 mgL−1) was more pronounced than that of nutmeg powder (96 h LC50 = 36.95 mgL−1). Ethanolic extracts of nutmeg and mace were more toxic than their other organic solvent extracts. The ethanolic extract of mace (24 h LC50 = 13.33 mgL−1) was more effective than the ethanolic extract of nutmeg (24 h LC50 = 18.04 mgL−1) in killing the test animals. The 96 h LC50 of column purified fraction of mace was 2.77 mgL−1 whereas that of nutmeg was 3.98 mgL−1. Nutmeg and mace may be used as potent molluscicides.

Treatment of the snail Lymnaea acuminata, the vector for the liver flukes Fasciola hepatica and Fasciola gigantica, with two alkylating agents (cyclophosphamide and busulfan) and one thiocarbamide (thiourea) caused reduction in the number of eggs and production of non-viable embryos. All the three drugs caused reduction in the levels of DNA, RNA and protein and the activity of alkaline phosphatase in the gonadal tissues of this snail. There was enhancement in free amino acid levels and activity of acid phosphatase by these drugs. Discontinuation of treatment could not reverse the cytotoxic effects of these drugs. Treatment of sterilized snails with prostaglandin E1 (PGE1), prostaglandin F2 alpha (PGF2 alpha) or hydrogen peroxide not only restored the number of eggs but also caused full embryonic development. Also, there was near total recovery of RNA, DNA and protein levels and small changes in free amino acid levels as well as the activity of alkaline and acid phosphatase. It has been suggested that the prostaglandins play a modulatory role in protein synthesis. The possible therapeutic use of PGE1, PGF2 alpha and H2O2 has been pointed out.

Cyclophosphamide induced changes in the ovotestis of the snail Lymnaea acuminata, the vector of the giant liverflukes Fasciola hepatica and Fasciola gigantica were studied in order to explore potential of the drug as a chemosterilant for snails. The drug caused a dose dependent reduction in the levels of DNA, RNA and proteins and the activity of the enzyme alkaline phosphatase. It increased the activity of acid phosphatase and the levels of total free amino acids in the ovotestis. While the animals showed nearly total recovery in RNA and DNA levels 7 days after termination of drug treatment, changes produced in protein, amino acid levels and phosphatase activity did not show any recovery. It appears that cyclophosphamide, while affecting its primary targets i.e. DNA and RNA, irreversibly inhibits protein synthesis through other cellular enzymes as well.

Several aspects of carbohydrate metabolism following 24 hr and 48 hr treatment with 10 and 20 mg/l of trichlorfon, were studied in hepatopancreas, mantle, intestine and foot of the snail. Lymnaea acuminata. Following treatment with the pesticide, the rate of oxygen consumption and concentration of glycogen were reduced, while the levels of lactic acid and reducing sugars were enhanced. Withdrawal of pesticide for 7 days following trichlorfon treatment (10 mg/l for 48 hrs) could not reverse these changes.

Every month during the year 2006–2007, the 24, 48, 72 and 96 h LC50values of a molluscicide, cypermethrin, were determined for a snailLymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50values of 10.39, 10.90 and 11.19 mg l− 1during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50was 65.84 mg l− 1.There was a significant positive correlation between LC50of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

Latex extract of the medicinal euphorbious plants, Jatropha gossypifolia, Euphorbia pulcherima, and Croton tiglium were tested as molluscicides in natural ponds against the freshwater snail Lymnaea acuminata. The molluscicidal activity of latex extracts of all the three plants was time and dose dependent at all the exposure periods. A significant negative correlation between LC values of latex extracts and exposure periods existed, thus LC50 values decreased from 17.32 mg/L (24 h) to 5.66 mg/L (96 h) in case of Jatropha gossypifolia, 3.79 mg/L (24 h) to 1.56 mg/L (96 h) in case of Euphorbia pulcherima and 12.32 mg/L (24 h) to 4.85 mg/L (96 h) in case of Croton tiglium against Lymnaea acuminata. The latex of all the three euphorbiales may probably be used as potent eco-friendly molluscicides in natural ponds for managing the harmful snail population.

During the survey of freshwater snail hosts and their digenean larval trematode parasites, a rare cercaria larva belonging to family Transversotrematidae and subclass Digenea (Trematoda) was recovered from the snail species Melanoides striatella tuberculata inhabiting perennial Som river of Udaipur district, Rajasthan, India. More than 28 % mature specimens of these snails were found to be infected with transversotrematid cercaria larvae in the spring season. Body of this cercaria is large, bowl-shaped, biocellate, spinose, transparent and laterally extended having two pigmented eye spots, two hold fast organs extended from the junction of body and tail, large tail with two foliated furcal rami, and cyclocoel intestinal caeca. As far as the authors are aware, this is the first record of a transversotrematid larva from Rajasthan, India. Simultaneously, other forms of cercariae viz., amphistome, echinostome, monostome, gymnocephalous, furcocercous and xiphidiocercous cercariae were also recovered from fifteen species of pulmonate and operculate snails including Lymnaea acuminata f. patula, L. acuminata f. chlamys, L. acuminata f. typica, L. acuminata f. rufescens, L. luteola f. australis, L. luteola f. typica, L. luteola f. impura, Planorbis (Indoplanorbis) exustus, and Anisus (Gyraulus) convexiusculus, Faunus ater, Melania (Plotia) scabra, Thiara (Tarebia) lineata, Melanoides striatella tuberculata, Vivipara bengalensis race gigantica and V. bengalensis race mandiensis. The seasonal occurrence and host-specificity of diverse trematode cercaria larvae are also discussed besides the first record of a rare transversotrematid cercaria larva from Rajasthan, India.

Fasciolosis is a waterborne disease, caused byFasciolaspecies. SnailLymnaea acuminatais an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails.

Various properties of alginates, such as its biodegradability, nontoxicity, biocompatibility, and ability to form gel with a variety of crosslinking agents in mild and aqueous conditions, make it a very useful binding matrix. Use of alginates as binding matrix for bio-molluscicides (crude Annona squamosa powder and acetogenin extracted from the seed powder of A. squamosa) is explored in this article. Effect of different crosslinkers as well as different loaded concentrations of biomolluscicides on the release were studied The release of the biomolluscicides extended over 25 and 20 days, respectively. The release was affected by the type of crosslinker and the amount of loaded concentration of the molluscicides. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Molluscicidal activity of cow urine alone and with different additives was studied against Lymnaea acuminata. The toxicity of cow urine kept for 15 days in sunlight (8 h/day) or ambient laboratory conditions against the snail was time- and concentration-dependent. The pH of fresh cow urine is 7.4 which changes to 10.9 when kept for 15 days in laboratory; exposure to sunlight for the same period alter the pH to 10.85. Binary combinations (1:1) of freeze-dried cow urine kept for 15 days separately with each of Allium sativum (Liliaceae) bulb powder, Azadirachta indica (Meliaceae) oil, Annona squamosa (Annonaceae) seed powder, Ferula asafoetida (Apiaceae) root latex and tea leaves, and Camellia sinensis (Theaceae) were more toxic to the snail than treatment with urine alone. Additives to cow urine in sunlight were more effective than those under laboratory conditions.

Effects of sublethal exposure to cypermethrin and alphamethrin on the reproductive physiology and oxidative metabolism of the freshwater snail, Lymnaea acuminata, were studied. Sublethal exposure to both pyrethroids caused increases in the numbers of egg masses and eggs at all concentrations, but the survival rate of the snails was significantly reduced 28 days after of hatching. Both pyrethroids altered the oxidative metabolism in hepatopancreas and ovotestis tissues of the snails. Stress conditions result in less availability of oxygen and in turn less ATP production in tissues, adversely affecting oxidative metabolism and reproduction in L. acuminata.

Adult Lymnaea acuminata (average length 20-22 mm) were collected locally from lakes and low-lying submerged fields from Gorakhpur. The chemoattraction studies were made in round glass aquaria measuring 30 cm in diameter and filled to a depth of 10 mm with 500 ml dechlorinated tap water. Each aquarium was divided into four concentric zones. At the starting time of the assay 10 snails were placed on the circumference of outermost zone 0. Snail attractant pellets (SAP) were added simultaneously in the center of central zone 3. SAP of different amino acids were prepared at concentrations of 10, 20, 50, 80 and 100 mM/2% agar solution and, subsequently, spread to a uniform thickness of 5 mm. After cooling, SAP were cut in small pieces of 5 mm in diameter. Lymnaea acuminata's attraction to amino acids was studied using different amino acid concentrations in SAP. Pellets containing amino acids with non-polar R groups (proline and tryptophan), a charged polar group (arginine) and uncharged polar R groups (serine, citrulline and asparagine) were tested. The snails were more attracted to the uncharged polar R group amino acid serine than to other groups of amino acids. The preferred amino acid concentration was 80 mM. The attraction of snails to different amino acids was concentration dependent. Snails could discriminate amongst the different amino acids at > or = 50 mM.