Dietary Supplement of Medicinal Herbal Leaf Powder on Growth Performance,Digestive Enzymes Activities,Energy Utilization and Vitamin Levels of the Freshwater Prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis>

Experiments were conducted to evaluate the influence of dietary supplement (@ 5%) dried leaf powder of the medicinal herbs, Ocimum sanctum, Solanum trilobatum and Phyllanthus amarus on survival, growth, activities of digestive enzymes, energy utilization, and vitamin contents of the freshwater prawn, Macrobrachium rosenbergii. Results indicated significant (P < 0.05) improvements in survival, growth, activities of digestive enzymes, energy utilization, and vitamin levels in herb supplemented feeds fed prawns group compared to prawns fed non-herbs feed. Best growth was noted in prawns fed with the feed supplemented by leaf powder of P. amarus, followed by S. trilobatum and O. sanctum. It is concluded that leaf powder of these herbs can be used as dietary supplement for better growth of freshwater prawn.     

Effects of Probiotics on Survival,Growth and Digestive Enzymes Activities in Freshwater Prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis> (De Man 1879)

A study was conducted to examine the effects of three probiotics, Lactobacillus sporogenes, Bacillus subtilis and Saccharomyces cerevisiae on the survival, growth and digestive enzymes activities of the freshwater prawn Macrobrachium rosenbergii post larvae (PL). The probiotics, L. sporogenes (4 %), B. subtilis (3 %) and S. cerevisiae (4 %) were taken and mixed with basal diet. Diet without probiotics served as control. These probiotics diets were fed to M. rosenbergii PL for a period of 60 days. After the feeding trail, the growth parameters such as survival, weight gain, specific growth rate and protein efficiency rate were found to be significantly (P < 0.05) higher in 4 % S. cerevisiae incorporated diet fed PL when compared with control. In the case of feed conversion rate just the reverse was seen (P < 0.05) at this concentration. This indicates its superior quality among different concentrations of probiotics tested. Activities of digestive enzymes, such as protease, amylase and lipase were significantly (P < 0.05) higher at this concentration (4 % S. cerevisiae). Some of essential and non-essential amino acids also significantly elevated in probiotics supplemented diet fed prawns. This study indicated that probiotics, S. cerevisiae incorporated diets were beneficial for M. rosenbergii in terms of increasing growth, enzyme and amino acid production.     

Thermal limits for the establishment and growth of populations of the invasive apple snail <Emphasis Type="Italic">Pomacea canaliculata</Emphasis>

Pomacea canaliculata is a South American freshwater snail considered as one of the world’s worst invasive alien species. A temperature of around 25 °C has usually been considered to be optimal for rearing P. canaliculata. Nevertheless, snails have not been reared under a wide range of temperatures to reveal the optimum for performance in terms of population increase. We investigated the effect of temperature on growth, survival and reproduction, estimating demographic parameters for P. canaliculata in the wide range of temperatures at which these snails are active (15–35 °C). No reproductive activity was evidenced for the snails reared at 15 °C, probably explained by the small sizes attained at this temperature. Temperatures above 25 °C did not promote a significant acceleration in growth so higher temperatures will not result in a reduction in time to reach maturity. In fact, snails from 25 and 30 °C began reproduction at the same age. We report here for the first time a detrimental effect of high temperatures that provoked a significant decrease in the contribution of snails to the next generation: the viability of eggs from the snails reared at 30 °C was very low and the snails exposed to a constant water temperature of 35 °C were unable to produce eggs. Our findings reveal a new environmental constraint that could be a determinant of the range limits of this species in invaded regions, especially during the coming decades, anticipating the scenario predicted from global warming.     

Food web interactions determine energy transfer efficiency and top consumer responses to inputs of dissolved organic carbon

The sand stored in the gizzard of some freshwater snails should assist in the mechanical digestion of tough food, yet effects of gizzard sand on consumption of living macrophyte tissue are seldom addressed. We quantified the effects of gizzard sand both on consumption of plant tissue and on snail growth and reproduction with a cross-gradient, 28-day laboratory experiment. We offered apical shoot sections of Myriophyllum spicatum (initial ash content ~ 56%) or soft lettuce (ash content ~ 19%, as control) to Lymnaea stagnalis previously reared on sand or without sand. Gizzard sand had no effect on snail growth but sand-reared snails fed with lettuce initially produced more eggs than their no-sand counterparts. Snails fed M. spicatum exhibited stunted growth and produced only one small egg clutch. Shell height at time of first oviposition of M. spicatum-fed snails was two-thirds of that of lettuce-fed controls. Snails initially appeared to feed on periphyton and older, brownish M. spicatum leaflet tips, but later turned to midstem tissue. Fresh apices were not consumed. Gizzard sand had a limited effect on the ability of L. stagnalis to consume living M. spicatum, with apices likely defended chemically (polyphenols) and midstem tissue defended structurally (high ash content).     

Life history traits determine the differential vulnerability of native and invasive apple snails (<Emphasis Type="Italic">Pomacea</Emphasis> spp.) to a shared juvenile-stage predator

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.     

Seasonal distribution of the invasive snail, <Emphasis Type="Italic">Bithynia tentaculata,</Emphasis> within infested waterbodies in Minnesota,USA, including waterfowl migration

The introduction of the invasive faucet snail (Bithynia tentaculata) and its associated trematodes, Cyathocotyle bushiensis, Sphaeridiotrema spp., and Leyogonimus polyoon, has resulted in recurring waterfowl die-offs during spring and fall migration in the Great Lakes Region, especially of Lesser scaup (Aythya affinis) and American coots (Fulica americana). Here we evaluated faucet snail habitat use and abundance in infested waterbodies in northcentral Minnesota (USA) during spring, summer, and fall of 2011–2013. We collected snail samples, along with data on abiotic and biotic variables, at 12 snail-infested waterbodies. We used Generalized Estimating Equations to develop models that explain variability in the distribution and abundance of snails within waterbodies. Models containing water depth consistently received considerable support in waterbodies where depth varied substantially; however the specific shape of these relationships varied among waterbodies. Snails used a wide range of depths, but were more likely to be present in deep portions (~6 m) of large lakes in all seasons. We found seasonal differences in the location of rafts of migrating scaup, with use of areas closer to shore in the spring, and use of areas shallower than those used most by faucet snails. Patterns in snail distribution likely influenced the availability of snails for consumption by migrating waterfowl; differences in portions of large lakes used by migratory waterfowl as stopover sites and by faucet snails may reduce exposure of migrating waterfowl to trematodes in infested lakes. However, some spatio-temporal overlap between snails and scaup occurs and explains the continuing loss of waterfowl to trematodiasis.     

Integrated control of tobacco black shank by combined use of riboflavin and <Emphasis Type="Italic">Bacillus subtilis</Emphasis> strain Tpb55

We investigated the effect of riboflavin on the biocontrol activity of Bacillus subtilis Tpb55 against Phytophthora nicotianae (Pn), which causes tobacco black shank. Riboflavin (0.2 mg ml^?1) significantly improved the biocontrol activity of Tpb55 (2.0 × 10⁸ cfu ml^?1). Riboflavin (0.02–0.5 mg ml^?1) alone could not significantly inhibit Pn growth. However, it enhanced the B. subtilis population, both in vitro and in tobacco roots and significantly increased the activity of defense enzymes, peroxidase, catalase, superoxide dismutase, and β-1,3-glucanase, in the roots of B. subtilis-treated tobacco seedlings. Our results indicate that riboflavin can stimulate the growth of B. subtilis Tpb55 and induce resistance to Pn in tobacco plants. These findings should boost the prospects for practical application of B. subtilis Tpb55 as a biocontrol agent against black shank of tobacco.     

Cadmium,chromium, and lead accumulation in aquatic plants and animals near a municipal landfill

This research was conducted to assess the contamination of heavy metals in the water, sediment, aquatic plants and animals around a municipal landfill. The heavy metals were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations of cadmium (Cd), chromium (Cr), and lead (Pb) in water and sediment were Not detected (ND), 0.05 ± 0.98, and 0.02 ± 0.01 mg/L; and 0.47 ± 0.23, 18.65 ± 11.39, and 5.36 ± 2.08 mg/kg, respectively. A total of 24 aquatic plants from 4 species were collected from the municipal landfill. Cd concentrations in all plant species were within the standard, while Cr and Pb exceeded the standard. Forty-four fish from 4 species, 29 freshwater snails from 3 species, 10 freshwater prawns from 1 species, and 9 freshwater crabs from 1 species were collected. Cd and Cr concentrations in 2 species of fish samples exceeded the standard and Pb concentration in all fish species exceeded the standard. Cd and Pb concentrations in all freshwater snails were within the standard, except Cr. Meanwhile, Cd and Pb in freshwater prawns and snails were within the standard, except Cr. Five species of frogs were collected. Cd and Cr concentrations in 2 species exceeded the standard. Pb concentrations in all frog species exceeded the standard. The pattern of metal accumulation was fish > frogs > freshwater snails > freshwater prawns = freshwater crab (Cd), freshwater prawn > frogs > freshwater crab = freshwater snail > fish (Cr), and freshwater prawn > fish > frogs > freshwater snail > freshwater crab (Pb).     

Development of a powder formulation based on <Emphasis Type="Italic">Bacillus</Emphasis><Emphasis Type="Italic">cereus</Emphasis> sensu lato strain B25 spores for biological control of <Emphasis Type="Italic">Fusarium verticillioides</Emphasis> in maize plants

Maize is an economically important crop in northern Mexico. Different fungi cause ear and root rot in maize, including Fusarium verticillioides (Sacc.) Nirenberg. Crop management of this pathogen with chemical fungicides has been difficult. By contrast, the recent use of novel biocontrol strategies, such as seed bacterization with Bacillus cereus sensu lato strain B25, has been effective in field trials. These approaches are not without their problems, since insufficient formulation technology, between other factors, can limit success of biocontrol agents. In response to these drawbacks, we have developed a powder formulation based on Bacillus B25 spores and evaluated some of its characteristics, including shelf life and efficacy against F. verticillioides, in vitro and in maize plants. A talc-based powder formulation containing 1 × 10⁹ c.f.u. g^?1 was obtained and evaluated for seed adherence ability, seed germination effect, shelf life and antagonism against F. verticillioides in in vitro and in planta assays. Seed adherence of viable bacterial spores ranged from 1.0 to 1.41 × 10⁷ c.f.u. g^?1. Bacteria did not display negative effects on seed germination. Spore viability for the powder formulation slowly decreased over time, and was 53 % after 360 days of storage at room temperature. This formulation was capable of controlling F. verticillioides in greenhouse assays, as well as eight other maize phytopathogenic fungi in vitro. The results suggest that a talc-based powder formulation of Bacillus B25 spores may be sufficient to produce inoculum for biocontrol of maize ear and root rots caused by F. verticillioides.     

Paleoecological and isotopic analysis of fossil continental mollusks of Sandelzhausen (Miocene,Germany)

The fossil molluscan fauna of Sandelzhausen (Early/Middle Miocene, SE Germany) comprises a total of 44 species, mostly terrestrial pulmonate snails. Herein we present a paleoecological analysis of this fauna based on an actualistic approach and on data on stable isotopes of carbon and oxygen (assessed from specimens of the freshwater lymnaeid snail Galba dupuyiana and the terrestrial clausiliid snail Pseudidyla moersingensis). The paleoecological reconstruction achieved here is in line with previous works, with some novelties and minor modifications. The basal sediment layers point to a swampy area with ponds and/or oxbow lakes (closed system, as indicated by the covariation between oxygen and carbon isotopic signals of G. dupuyiana), prone to seasonal flooding events. This environment would then gradually transition into a perennial lake, as indicated by: the proportion of planorbids, the appearance of aquatic species intolerant to desiccation, and the decoupling of the covariation between oxygen and carbon isotopic signals of G. dupuyiana. The terrestrial habitat would have developed from a more open environment (semi-arid/sub-humid scrubland) to a sub-humid/humid denser forest afterwards. Still, species from drier and more open environments are present throughout all the layers, suggesting that these habitats persisted in the lake’s hinterland. The mean annual temperature, calculated from the oxygen isotopic composition of P. moersingensis, ranges from 18.5 to 20.5 °C, but with no significant trend of change throughout the layers.     

Geographic variation in thermal tolerance and strategies of heat shock protein expression in the land snail <Emphasis Type="Italic">Theba pisana</Emphasis> in relation to genetic structure

Land snails are exposed to conditions of high ambient temperature and low humidity, and their survival depends on a suite of morphological, behavioral, physiological, and molecular adaptations to the specific microhabitat. We tested in six populations of the land snail Theba pisana whether adaptations to different habitats affect their ability to cope with thermal stress and their strategies of heat shock protein (HSP) expression. Levels of Hsp70 and Hsp90 in the foot tissue were measured in field-collected snails and after acclimation to laboratory conditions. Snails were also exposed to various temperatures (32 up to 54 °C) for 2 h and HSP messenger RNA (mRNA) levels were measured in the foot tissue and survival was determined. To test whether the physiological and molecular data are related to genetic parameters, we analyzed T. pisana populations using partial sequences of nuclear and mitochondrial DNA ribosomal RNA genes. We show that populations collected from warmer habitats were more thermotolerant and had higher constitutive levels of Hsp70 isoforms in the foot tissue. Quantitative real-time polymerase chain reaction (PCR) analysis indicated that hsp70 and hsp90 mRNA levels increased significantly in response to thermal stress, although the increase in hsp70 mRNA was larger compared to hsp90 and its induction continued up to higher temperatures. Generally, warm-adapted populations had higher temperatures of maximal induction of hsp70 mRNA synthesis and higher upper thermal limits to HSP mRNA synthesis. Our study suggests that Hsp70 in the foot tissue of T. pisana snails may have important roles in determining stress resistance, while Hsp90 is more likely implicated in signal transduction processes that are activated by stress. In the phylogenetic analysis, T. pisana haplotypes were principally divided into two major clades largely corresponding to the physiological ability to withstand stress, thus pointing to genetically fixed tolerance.     

Two for one: inadvertent introduction of <Emphasis Type="Italic">Euglandina</Emphasis> species during failed bio-control efforts in Hawaii

The introduction of the predatory land snail, Euglandina rosea (Férrusac, 1821) from Florida to Hawaii to control the giant African snail, Lissachatina fulica (Bowdich, 1822) is among the most publicized biological control cases gone awry. Following preliminary genetic analyses that revealed a second, possibly undescribed Euglandina species was probably introduced to Hawaii, we used an integrative systematic approach combining both genetic and morphological assessments to examine the taxonomic status of the snail referred to as E. rosea in Hawaii. Genetic and morphological analyses support the interpretation that two Euglandina species were introduced to and have become established in Hawaii and can be readily distinguished based on morphological differences. This finding has significant ramifications for understanding both historical and contemporary biocontrol as it suggests that: (1) other species may have been inadvertently introduced through bio-control programs, (2) inadequate understanding of the taxonomy of bio-control agents has obscured our ability to effectively study their ecological impacts, and (3) while the US has no comprehensive regulatory framework for importing biological control agents, one is urgently needed. This also has wide-ranging implications for conservation efforts throughout the tropics because Euglandina from Oahu, Hawaii were released on other Hawaiian Islands, New Guinea, Okinawa, Palau Islands, Philippines, India, Bonin Islands and Bermuda for use in biological control programs that led to catastrophic loss of endemic land snail diversity.     

Geographic patterns of genetic variation in nuclear and chloroplast genomes of two related oaks (<Emphasis Type="Italic">Quercus aliena</Emphasis> and <Emphasis Type="Italic">Q. serrata</Emphasis>) in Japan: implications for seed and seedling transfer

In this study, we assessed geographic patterns of genetic variations in nuclear and chloroplast genomes of two related native oaks in Japan, Quercus aliena and Q. serrata, in order to facilitate development of genetic guidelines for transfer of planting stocks for each species. A total of 12 populations of Q. aliena and 44 populations of Q. serrata were analyzed in this study. Genotyping of nuclear microsatellites in Q. aliena was done with only nine populations (n = 212) due to limited numbers of individuals in two populations, while all 12 populations (n = 89) were used in sequencing chloroplast DNA (cpDNA). In Q. serrata, 43 populations (n = 1032) were genotyped by nuclear microsatellite markers, while cpDNA of 44 populations (n = 350) was sequenced. As anticipated, geographic patterns detected in the variations of Q. aliena’s nuclear genome and its chloroplast haplotype distribution clearly distinguished northern and southern groups of populations. However, those of Q. serrata were inconsistent. The geographic distribution of its chloroplast haplotypes tends to show the predicted differentiation between northern and southern lineages, but geographic signals in the genetic structure of its nuclear microsatellites are weak. Therefore, treating northern and southern regions of Japan as genetically distinct transferrable zones for planting stocks is highly warranted for Q. aliena. For Q. serrata, the strong NE-SW geographic structure of cpDNA should be considered.     

Linkages of <Emphasis Type="Italic">Firmicutes</Emphasis> and <Emphasis Type="Italic">Bacteroidetes</Emphasis> populations to methanogenic process performance

To identify potential linkages between specific bacterial populations and process performance in anaerobic digestion, the dynamics of bacterial community structure was monitored with high-throughput sequencing in triplicate anaerobic digesters treating animal waste. Firmicutes and Bacteroidetes were found as the two most abundant populations, however, with contrasting population dynamics in response to organic overloading. Firmicutes dominated the bacterial community during stable process performance at low organic loading rate, representing over 50 % of the bacterial abundance. In contrast, the onset of organic overloading raised the relative abundance of Bacteroidetes from 20 ± 2.6 to 44 ± 3.1 %. In addition to the significant negative correlation between the relative abundance of Firmicutes and Bacteroidetes, populations of Firmicutes and Bacteroidetes were found to be linked to process parameters including organic loading rate, volatile fatty acids concentration, and methane production. Therefore, the population abundance ratio of Firmicutes to Bacteroidetes (F/B ratio) was suggested as a potential indicator for process performance. The interactions between Firmicutes and Bacteroidetes populations could be exploited to develop strategies for the prevention of performance perturbation in anaerobic digestion processes.     

Alterations in Digestive Enzymes of Three Freshwater Teleostean Fishes by Almix Herbicide: A Comparative Study

Three freshwater teleostean fishes viz., Anabas testudineus (Bloch), Heteropneustes fossilis (Bloch) and Oreochromis niloticus (Linnaeus) were exposed to almix (66.67 mg/l) herbicide for 30 days to investigate the activity of digestive enzymes (amylase, lipase and protease) in stomach, intestine and liver. Amylase activity showed significantly high (p < 0.05) in all the fishes compared to control value and highest activity was observed in liver of A. testudineus (721.99 %) and minimum in intestine of H. fossilis (195.37 %). Lipase activity was also significantly increased (p < 0.05) in all the tissues; but highest in intestine of O. niloticus (235.51 %) and minimum in intestine of A. testudineus (130.51 %). Protease activity also showed similar trends of enhancement; it was maximum in stomach of O. niloticus (362.69 %), whereas in liver of H. fossilis it was rather less (173.72 %). Increased activity of digestive enzymes resulting from tissue damage ultimately affected the fish health due to impairment of digestive physiology confirming the herbicidal contamination on fish species. The sensitivity to the almix herbicide was pronounced in the order of O. niloticus > A. testudineus > H. fossilis.     

Antifungal performance of extracellular chitinases and culture supernatants of <Emphasis Type="Italic">Streptomyces galilaeus</Emphasis> CFFSUR-B12 against <Emphasis Type="Italic">Mycosphaerella fijiensis</Emphasis> Morelet

The tropical and mycoparasite strain Streptomyces galilaeus CFFSUR-B12 was evaluated as an antagonist of Mycosphaerella fijiensis Morelet, causal agent of the Black Sigatoka Disease (BSD) of banana. On zymograms of CFFSUR-B12 culture supernatants, we detected four chitinases of approximately 32 kDa (Chi32), 20 kDa (Chi20), and two with masses well over 170 kDa (ChiU) that showed little migration during denaturing electrophoresis at different concentrations of polyacrylamide. The thymol-sulphuric acid assay showed that the ChiU were glycosylated chitinases. Moreover, matrix assisted laser desorption ionization time-of-flight MS analysis revealed that the ChiU are the same protein and identical to a family 18 chitinase from Streptomyces sp. S4 (gi|498328075). Chi32 was similar to an extracellular protein from Streptomyces albus J1074 (gi|478687481) and Chi20 was non-significantly similar to chitinases from five different strains of Streptomyces (P > 0.05). Subsequently, Chi32 and Chi20 were partially purified by anion exchange and hydrophobic interaction chromatography and tested against M. fijiensis. Chitinases failed to inhibit ascospore germination, but inhibited up to 35 and 62 % of germ tube elongation and mycelial growth, respectively. We found that crude culture supernatant and living cells of S. galilaeus CFFSUR-B12 were the most effective in inhibiting M. fijiensis and are potential biocontrol agents of BSD.     

Trophic plasticity among spring vs. cave populations of <Emphasis Type="Italic">Gammarus minus:</Emphasis> examining functional niches using stable isotopes and C/N ratios

In some environments, species may exhibit trophic plasticity, which allows them to extend beyond their assigned functional group. For Gammarus minus, a freshwater amphipod classified as a shredder or detritivore, cave populations have been observed consuming heterotrophs as well as shredding leaves, and therefore may be exhibiting trophic plasticity. To test this possibility, we examined the C and N stable isotope and C/N ratios for cave and spring populations of G. minus. A 15-day feeding experiment using leaves and G. minus from a spring population established that the diet-tissue discrimination factor was 3.2 ‰ for δ¹⁵N. Cave G. minus were 8 ‰ higher in δ¹⁵N relative to cave leaves, indicating they did not derive nitrogen from leaves, whereas field collected spring populations were 2–3 ‰ higher than spring leaves, indicating that they did. Cave G. minus were 2.6 ‰ higher in δ¹⁵N than the cave isopod, Caecidotea holsingeri. Relative to spring populations, Organ Cave G. minus were ¹⁵N enriched by 6 ‰, suggesting they occupied a different trophic level, or incorporated an isotopically distinct N source. While stable isotopes cannot tell what the cave G. minus are eating, the isotopes certainly show that G. minus are not eating leaves and are trophically distinct form the surface populations. Differences in C/N ratios were observed, but reflect the size of the G. minus examined and not feeding group or habitat. The isotope data strongly support the hypothesis that cave populations of G. minus have become generalist or omnivorous by including animal protein in their diet.     

Hybridization success is largely limited to homoploid <Emphasis Type="Italic">Prunus</Emphasis> hybrids: a multidisciplinary approach

Prunus fruticosa is a rare shrub occurring in Eurasian thermophilous forest-steppe alliances. The species frequently hybridizes with cultivated Prunus species in Europe (allochthonous tetraploid P. cerasus and partly indigenous diploid P. avium). Propidium iodide flow cytometry, distance-based morphometrics, elliptic Fourier analysis and embryology were employed to evaluate the extent of hybridization in six Slovak populations. Flow cytometric analyses revealed three ploidy levels: diploid (P. avium), triploid (P. × mohacsyana) and tetraploid (P. fruticosa, P. × eminens and P. cerasus). In addition, P. fruticosa and P. cerasus, at the tetraploid level, were found to differ in absolute genome size. An embryological evaluation suggested the existence of a triploid block in P. × mohacsyana and significant potential for hybridization among tetraploid taxa (indicated also by a continuous distribution of genome size data and further mirrored by morphometrics). Although hybrids significantly differ in ploidy level and embryological characteristics, they are almost indistinguishable using morphological characters. Hybridization with P. cerasus thus turns out to be a significant threat to wild populations of P. fruticosa compared to the relatively weak influence of P. avium.     

The Prawn Macrobrachium vollenhovenii in the Senegal River Basin: Towards Sustainable Restocking of All-Male Populations for Biological Control of Schistosomiasis

Early malacological literature suggests that the outbreak of schistosomiasis, a parasitic disease transmitted by aquatic snails, in the Senegal River basin occurred due to ecological changes resulting from the construction of the Diama dam. The common treatment, the drug praziquantel, does not protect from the high risk of re-infection due to human contact with infested water on a daily basis. The construction of the dam interfered with the life cycle of the prawn Macrobrachium vollenhovenii by blocking its access to breeding grounds in the estuary. These prawns were demonstrated to be potential biological control agents, being effective predators of Schistosoma-susceptible snails. Here, we propose a responsible restocking strategy using all-male prawn populations which could provide sustainable disease control. Male prawns reach a larger size and have a lower tendency to migrate than females. We, therefore, expect that periodic restocking of all-male juveniles will decrease the prevalence of schistosomiasis and increase villagers'' welfare. In this interdisciplinary study, we examined current prawn abundance along the river basin, complemented with a retrospective questionnaire completed by local fishermen. We revealed the current absence of prawns upriver and thus demonstrated the need for restocking. Since male prawns are suggested to be preferable for bio-control, we laid the molecular foundation for production of all-male M. vollenhovenii through a complete sequencing of the insulin-like androgenic gland-encoding gene (IAG), which is responsible for sexual differentiation in crustaceans. We also conducted bioinformatics and immunohistochemistry analyses to demonstrate the similarity of this sequence to the IAG of another Macrobrachium species in which neo-females are produced and their progeny are 100% males. At least 100 million people at risk of schistosomiasis are residents of areas that experienced water management manipulations. Our suggested non-breeding sustainable model of control—if proven successful—could prevent re-infections and thus prove useful throughout the world.