"In-vitro Effects of Chlorpyrifos and Monocrotophos on the Activity of Acetylcholinesterase (AChE) in Different Tissues of Apple Snail Pila globosa (Swainson, 1822)"

The impact of two organophosphorus insecticides [Chlorpyrifos (CPF) and Monocrotophos (MCP)] on non-target wild natural gastropod, Pila globosa (apple snail) from the paddy fields was studied. The activity of acetylcholinesterase (AChE) was monitored on foot-muscle and hepatopancreas tissues of control and exposed snails. In the foot- muscle AChE inhibition progressed and reached 54.19% and 63.13% of the control, whereas, the AChE inhibition in the hepatopancreas reached 46.96% and 53.67% over control after 48 hours of exposure to 1.5 mL.L-1 and 2.5 mL.L-1 CPF respectively. After 48 hours of MCP exposure at 1.5 mL.L-1 and 2.5 mL.L-1 separately, the AChE inhibition of foot muscle was 49.07% and 57.59% respectively while in hepatopancreas it was 44.65% and 48.84% respectively. Our results show more inhibition of AChE activities on the foot-muscle than hepatopancreas in a concentration and time-dependent manner with greater severity by CPF in comparison to MCP. AChE inhibition increased with the increasing exposure time.

Efficacy of Formulated Feed Preference and Stocking Density on Growth and Survival of Baby Pila globosa Reared in Laboratory Condition

Quality diet as food for raising freshwater snails under laboratory conditions has a significant effect on their growth and the number of egg clutches laid as well as on the size of the snail. Now a days, some innovative farmers of Bangladesh started snail culture within their fish farms in the view of producing snail to use as feed for their Prawn (Macrobrachiam rosenbergii), indigenous catfish (Clarius batrachus) farms, domestic duck farms and also as a protein supplement for preparing fish feed. From previous study we know that Bulinus nyassanus growth and survive rate was found well on locally formulated fish diet consisting of 30% crude protein with ingredients comprising fish meal, maize bran, rice bran, soya bean, wheat bran, hemicellulose (binder), vitamin premix and mineral premix. But no such research has been done in case of apple snail. The present study was aimed to investigate the feed formulation preferred by Pila globosa species and their effects on survival and growth of these snails in laboratory condition. Three type of formulated feed viz., pellet feed, fish meal and 50% fish meal + 50% crusted khudipana were used for the experiment in high and low stocking density of baby snails. The present findings shown that the diets in order of preference based on their effects on growth and survival of snails were formulated pellet feed, fish meal and 50% fish meal+ 50% crushed khudipana. After rearing of 28 days, highest growth found 0.32g with 86.66% survival with formulated diet in 60nos/L stocking density and 0.35g with 90% survival with formulated diet in 30nos/L stocking density. It`s indicate that the snails reared on formulated pellet feed diets and lower stocking density gave better performance in terms of survival and mean growth rate than those reared on other diets.

Cryptic speciation in freshwaters: are speciation in lentic species shaped by paleohydrological events?

The Indian subcontinent is extremely diverse in terms of its flora and fauna. However, there is a severe underestimation of the biotic diversity in invertebrate groups as well as a lack of understanding of the processes generating diversity in these groups. Here we aimed to jointly estimate the cryptic diversity of two freshwater snail species complexes, Pila globosa and Pila virens, and uncover the processes behind the speciation in these groups. We employed phylogenetic, morphometric, population genetic and niche modelling technique to address these questions. We found out that both species complexes consist of several genetically and ecologically distinct putative species. The speciation was primarily driven by allopatric isolation into different river basins. A combination of paleoclimatic and paleohydrological changes during the Miocene have shaped the speciation events. Local climatic adaptation also could have contributed towards some of the speciation events. The study sheds light on the complex interaction between the biology of the species and the environment that shape the diversification patterns in a group.

Temporal morphometric analyses of Pila globosa in India for its use in aquaculture and food industry

Background Although the apple snail Pila globosa is used as indicator species for human consumption locally and as fish feed, research on it in general is very scanty. It is used in food industry, in aquaculture as fish bait and used as food in many regions of India and many other countries, but research on it has been started in the 1970s. Only 40 articles are available on this organism in PubMed indicating an urgent need of basic research on it especially work on its spatiotemporal morphometry Therefore, sampling of P. globosa was done from different parts of India in different seasons (summer, winter and rainy), and different morphometric studies were performed on this organism to draw baseline information. Analysis was conducted to study morphometry, the relationship between shell length and the weight and relative condition factor of Indian apple snail Pila globosa collected from five zones (east, west, north, south and centre) of India during 2018–2019 year. Results The shell length (SL) (46.5 ± 13.33), shell width (SW) (40.22±11.5 mm), spire length (SPL) (2.99±0.15 mm), base length (BL) (12.53±2.94 mm), aperture length (AL) (21.95±4.36 mm), aperture width (AW) (2.74±0.47 mm) and shell weight (WT) (31.08±13.76 g) were observed to be varied among the individual sampled across India. Different relationships for SL/SW (Log SW=0.9889 Log SL + 0.9444), SL/SPL (Log SPL = 0.1452 Log SL+0.3815), SL/BL (Log BL=0.7789 Log SL+0.5814), SL/AL (Log AL= 0.6518 Log SL+0.9111) and SL/AW (Log AW=0.4475 Log SL+0.1422) were observed by considering shell length as basic index. The relationship between shell length and shell weight was found to be Log WT=2.0263 Log SL+0.1098. The relative condition factor revealed uninterrupted and good environmental condition observed for apple snails. A negative allometric growth pattern was observed from the length–weight relationship. Conclusion The environments of apple snail in India are not contaminated, and the results can be used as baseline data in aquaculture for model analysis and can be used as a reference for drawing relationship among different morphometric indices of P. globosa in India, as there is no such information available on it. The data can also be used for mass scale production of P. globosa for consumption by human and use in aquatic industries as fish feed.

Distribution of freshwater Mollusca in Koothaippar wetland ecosystem Tiruchirappalli District Tamil Nadu

Freshwater Mollusca form an important animal group of the wetland ecosystems. The distribution and availability in terms of number of species needs scientific attention. Present study is an attempt to document the available Molluscan forms in Koothaippar wetlands of Tiruchirappalli District. This study was carried out between summer 2013 to post-monsoon 2017. Nine species were recorded and among them 6 species belong to Gastropoda representing 2 orders, 3 families, 3 genera while 3 species were bivalves representing 1 order, 1 family and 2 genera. Bellamya bengalensis, Lamellidens marginalis and Pila globosa were the predominantly present molluscan fauna and are distributed throughout the year. Five species of Molluscan fauna (Pila virens, Pila scutata, Bellamya dissimilis, Indoplanorbis exustus and Lamellidens corrianus) are less abundant and Parreysia favidens was found to be rare species of the ecosystem. These Molluscan forms, representing different families ranging from 34% of Ampullariidae, 33% of Unionoida, 22% of Viviparoidae and 11% of Planorbidae. Percent distribution of these shelled organisms indicate that they represent 3 orders viz., 56% of Architaenioglossa, 33% of Unionoida and 11% of Hygrophila.

Overview of river prawn farming in Bangladesh.

In south-west Bangladesh, thousands of farmers have converted their paddy fields into ghers to accommodate profitable river prawn (Macrobrachium rosenbergii) culture, in which prawn is cultured with fish and rice. Prawn post-larvae (PLs) are stocked in May-June and harvested from November to January. Farmers stock wild PLs rather than hatchery-produced stock as production of the latter is limited and farmers consider them to be of lower quality. The average stocking density of PLs is 20,680 ha-1. A variety of feeds is used for prawn culture but the preferred feed is the freshwater snail, Pila globosa. The production of prawn is quite variable because of the simple culture method, averaging 432 kg ha-1 year-1. The prawn is a high-value product for the international market and almost all prawns are therefore exported.

Natural breeding of freshwater apple snail Pila globosa (Swainson) in pond and aquarium

The freshwater apple snail, Pila globosa is one of the most abundant and commercially valued molluscs. Over exploitation of P. globosa for prawn farming is an alarming condition. The present study is aimed at elucidating the breeding behavior and reproduction process of P. globosa. The natural breeding experiment was conducted in two ponds- a 52 decimal pond in Gopalgonj sadar and a 40 decimal pond in Kotalipara. The ponds were prepared by applying lime at the rate of 3 kg/decimal and then filled up with water up to 30cm. Wild snails were stocked at the rate of 600 no./decimal. Organic compost (cow-dung, mustard oilcake and urea at the ratio of 1:1:0.5at the rate of 2.5 kg/decimal respectively) spread throughout the pond. Several male and female specimens were collected from experimental gher and brought to the laboratory aquarium to observe their breeding behavior. At the bottom of aquarium substrate like plastic bottle, marbel, artificial tree etc. were provided for egg laying. Breeding involves three processes: copulation, fertilization and laying. Copulation occurs in water on moist land and it takes about 3-4 hrs, then both separated. Fertilization is internal in P. globosa. Egg laying started 2 or 3 days after copulation. They lay eggs in sheltered places or moist land near water in the dyke. A single female lays eggs average 387.89±167.65 no. per clot at a time. The time elapsed between the first and the last hatchings ranged from 6 to 25 days and for 80% of the 5 egg masses were studied. Considering all the eggs in the egg masses (n=1856) more than 60% of the eggs hatched within 13 days of the first hatching. It needs about 25 days for full clot to be hatched. In the laboratory condition hatching success was observed about 80%.