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Journal articles on the topic 'Snail shell growth'
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1
Rondelaud, D., A. Novobilský, J. Höglund, et al. "Growth rate of the intermediate snail host Galba truncatula influences redial development of the trematode Fascioloides magna." Journal of Helminthology 88, no. 4 (2013): 427–33. http://dx.doi.org/10.1017/s0022149x13000370.
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AbstractA total of 850 pre-adult Galba truncatula (shell height, 4 mm), originating from four French snail populations differing in shell height at the adult stage (from 6.5 to 12 mm), were individually subjected at 20°C to single-miracidium infections with Fascioloides magna. At day 75 post-exposure, the surviving snails were dissected, and rediae and cercariae were counted. Snail groups differed in shell growth during the experiment: from 1.8 ± 0.4 mm in group A up to 4.0 ± 1.1 mm in group D. The prevalence of F. magna infection, the numbers of free rediae and cercariae significantly increased together with increasing growth of infected snails during the experiment. Group A produced 1–6 first-generation rediae per snail and the mean daughter redia production ranged from 7.5 second-generation rediae (when a single first generation per snail developed) to 2.3 (6 first-generation rediae per snail). In contrast, up to ten first-generation rediae were noted in group D, and each mother redia gave daughter rediae with averages ranging from 1.5 (ten first-generation rediae per snail) to 13 (a single first generation per snail). In conclusion, the development of F. magna in G. truncatula exhibited both inter- and intrapopulation variability, where the development of rediae and cercariae was positively correlated with snail growth.
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A. N. Stringer, I., Karl E. C. Brennan, Melinda L. Moir, G. R. Parrish, Jonathan D. Majer, and G. H. sherley. "Population structure, growth and longevity of Placostylus hongii (Pulmonata: Bulimulidae) on Tawhiti Rahi Island, Poor Knights Islands, New Zealand." Pacific Conservation Biology 9, no. 4 (2003): 241. http://dx.doi.org/10.1071/pc040241.
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Placostylus hongii, a threatened snail species, was studied on Tawhiti Rahi Island in the Poor Knights Islands group off the east coast of northern New Zealand between 1998 and 2000. Most live snails and empty shells were adults (83% and 85% respectively) and the low proportion of empty adult shells (36%) compared with live adult snails found in an area last burnt in the late 1950s suggests that the population there is still recovering. Growth was measured using snails recaptured with the aid of harmonic radar transponders attached to their shells. Increase in shell length varied from 6 to 25 mm per year in juveniles with shells >38 mm long, but it slowed when juveniles approached maturity (adult shell length 55-89 mm). The juvenile period is greater than three years and growth in shell length virtually stops when a thick aperture lip develops. This lip continues to thicken at 0.1-0.4 mm per year and can reach a maximum thickness of 15.5 mm, indicating that adults may live 10 years and possibly more than 30 years. A comparison of our data with two previous studies on the same population and on Aorangi Island, in the Poor Knights Islands group, confirms that these snails are slow developing, have low recruitment of adults, and that populations are probably maintained by a pool of long-lived adults. Our results indicate that following predator control on the mainland, the recovery of a snail population is likely to be slow. Once a population has recovered it could be maintained by intensively controlling rodents for periods of greater than three years (to allow recruitment of adults into the population) alternating with longer periods without control.
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Curtis, Lawrence A. "Growth, Trematode Parasitism, and Longevity of a Long-Lived Marine Gastropod (Ilyanassa Obsoleta)." Journal of the Marine Biological Association of the United Kingdom 75, no. 4 (1995): 913–25. http://dx.doi.org/10.1017/s0025315400038248.
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Ilyanassa obsoleta (Say) (Mollusca: Neogastropoda) is a conspicuous biotic element of marine / estuarine habitats along the eastern North American coast. Growth among larger individuals (-18–30 mm shell height) has not been assessed. Trematode infections are common in this group and their effect on growth must be considered. Snails were individually marked, measured, and released on the Cape Henlopen sand-flat at the mouth of Delaware Bay. Shell height change (growth) and trematode parasitism were assessed in recaptured snails. Most or all growth occurred in June and July. Mean growth of uninfected snails was 1–2 mm per season. Snails that started out larger grew more slowly, but there was much individual variability. Mean growth of parasitized snails was 0–2 mm per season and independent of initial size. The maximum age of this snail is currently documented at 7 y, which is too low. Size reflects age only approximately. However, the minimum and maximum age of a snail of given size, based on maximal and minimal growth per season, can be estimated. A mid-range estimate for lifespan of unparasitized and parasitized individuals is 30–40 y.
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Bieler, Rüdiger, Timothy M. Collins, Rosemary Golding, and Timothy A. Rawlings. "A novel and enigmatic two-holed shell aperture in a new species of suspension-feeding worm-snail (Vermetidae)." PeerJ 7 (February 28, 2019): e6569. http://dx.doi.org/10.7717/peerj.6569.
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Shell aperture modifications are well known in terrestrial and aquatic gastropods, with apertural lip thickening and tooth development common in species with terminal (determinate) shell growth. In contrast, secondary shell openings are rare in snails and are largely limited to slit shells, keyhole limpets, and abalone of the Vetigastropoda. When such features occur in other groups, they are noteworthy and raise interesting questions concerning the functional/adaptive significance of these shell modifications. Here we report on one such modification in a newly described species of vermetid snail. Members of the worm-snail family Vermetidae are sessile, suspension-feeding caenogastropods found in warm temperate to tropical marine environments worldwide. As juveniles, vermetids permanently cement their shells to hard substrata and subsequently produce irregularly coiled polychaete-like shell tubes with indeterminate growth and typically a simple circular shell aperture. In one previously studied group (genusCupolaconcha), the aperture can be covered by a shell dome with a central slit that retains its widest opening in the center of the aperture. Vermetid specimens collected in the barrier reefs of Belize and the Florida Keys show an extreme aperture modification previously unknown in Gastropoda, in which the shell opening is covered by an apertural dome that leaves two equal-sized circular holes, each corresponding to the inflow and outflow water exchange currents of the animal’s mantle cavity. The function of this perforated apertural dome is unknown, and it is in some ways antithetical to the suspension feeding habit of these snails. Further field and laboratory-based studies will be needed to clarify the functional significance and trade-offs of this unique morphology. The new taxon, which is not closely related to the previously described dome-building cladeCupolaconcha, is described and named asVermetus biperforatusBieler, Collins, Golding & Rawlings n. sp.
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Miller, Aroha A., and Robert Poulin. "Parasitism, movement, and distribution of the snail Diloma subrostrata (Trochidae) in a soft-sediment intertidal zone." Canadian Journal of Zoology 79, no. 11 (2001): 2029–35. http://dx.doi.org/10.1139/z01-167.
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Despite reports of their effects on host reproduction, growth, survival, and habitat use, the role of parasites in determining community structure is still poorly understood. Trematode infections in snails are a ubiquitous feature of intertidal systems worldwide. In this study, the influence of a trematode parasite on the movement and dispersal of the trochid snail Diloma subrostrata on a soft-sediment shore is examined using markrecapture experiments. The natural densities and shell widths of the snail peak between the upper and lower portions of the intertidal zone; marked snails were released within this area. Parasitized snails tended to have larger shells than nonparasitized conspecifics, and larger snails tended to move a greater linear distance than smaller snails in the 24 h following their marking and release. After shell width was corrected for, parasitized snails were found to move a significantly shorter distance than nonparasitized snails. In addition, the mean direction chosen by parasitized snails was almost parallel to the water's edge, whereas that taken by nonparasitized snails was almost directly toward the upper portion of the intertidal zone. Although the mean directions taken by the two types of snails were statistically different, the considerable scatter in the distributions of directions taken by individual snails casts a doubt over the biological significance of the result. Without detailed knowledge of the parasite's full life cycle it is difficult to determine whether this small bias in the direction of dispersal is an adaptive manipulation of snail behaviour by the parasitic trematode. Nevertheless, these results show that the trematode limits the range of movement, and possibly the direction of movement, of parasitized D. subrostrata, and can therefore contribute to the spatial structuring of the snail population.
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Mažuran, Neda, and Goran Kovačević. "Growth and Reproduction of Planorbarius corneus (Linnaeus, 1758) in Laboratory Conditions." Croatian Journal of Fisheries 79, no. 3 (2021): 111–18. http://dx.doi.org/10.2478/cjf-2021-0012.
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Abstract This study presents the results of observation on growth and reproduction of Planorbarius corneus (Linnaeus, 1758) (Gastropoda, Pulmonata) over the course of several years of continuous rearing in the laboratory in order to use them as test organisms for toxicity testing of chemicals. Some growth and reproduction features (shell diameter increase, fecundity, hatching time and rate, age at first reproduction, juvenile survival), which could provide more information for culturing P. corneus in the laboratory, are presented. The quantitative results of growth and reproduction in laboratory conditions were obtained: heterogenous growth varied between 0.1 mm and 5.3 mm in individual snails, production of 0.6 egg masses per snail/day and 11 eggs per snail/day. A statistically significant negative correlation between initial snail size and growth was noticed. In the second part of the experiment, the reproductive output of 4 isolated snails was compared to that of permanently grouped snails. As a result, 2-fold decreased growth and 4-fold decreased reproductive output in the progeny of isolated animals was noticed.
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Ridwanudin, Asep, Muhammad Firdaus, Idham Sumarto Pratama, and Sigit Anggoro Putro Dwiono. "EFFECT OF VARIOUS DIETARY SEAWEEDS ON THE GROWTH OF GOLD-MOUTH TURBAN (Turbo chrysostomus L., 1758) AT LOMBOK, INDONESIA." Marine Research in Indonesia 41, no. 1 (2016): 21–26. http://dx.doi.org/10.14203/mri.v41i1.91.
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Gold-mouth turban (Turbo chrysostomus L., 1758) is an important source of protein for coastal people in Lombok, West Nusa Tenggara, Indonesia. In order to acquire its seed production technique, research on the culture of the species was carried out since 2012. Feed source is a key concern when culturing animal, including turban snail. Growth of gold-mouth turban fed with seaweed Gracilaria sp., Ulva spp., and Kappaphycus alvarezii was evaluated. Each diet was randomly assigned to triplicate groups of 30 snail juveniles with an initial body weight and shell length of 4.65 ± 0.00 g and 24.55 ± 0.08 mm, respectively. After six weeks feeding trial, snails fed with Gracilaria sp. diet had significantly higher (P < 0.05) in final weight, final shell length, weight gain, specific growth rate (SGR) and food intake compared to snails fed with Ulva spp. or K. alvarezii diets.
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Schmera, Dénes, Anette Baur, and Bruno Baur. "Size-dependent shell growth and survival in natural populations of the rock-dwelling land snail Chondrina clienta." Canadian Journal of Zoology 93, no. 5 (2015): 403–10. http://dx.doi.org/10.1139/cjz-2014-0307.
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Rock-dwelling land snails, feeding on algae and lichens that grow on stone surfaces, may influence the structure and function of these ecosystems. Yet, little is known about the life history of rock-dwelling snails. We performed a 30-month mark–release–resight study in four populations of Chondrina clienta (Westerlund, 1883) inhabiting vertical walls of abandoned limestone quarries on the Baltic island of Öland, Sweden, to assess growth rate and survival of juvenile snails and determine age at maturity. We marked 800 individuals ranging in shell height from 1.4 to 4.9 mm, released them in their original habitat, and remeasured their shell height at intervals of 6 months. Shell growth of juvenile C. clienta was affected by the site (quarry wall) and the size of the individual, being highest in medium-sized snails. Shell growth occurred during both summer and winter. Annual apparent survival rates of C. clienta were size-dependent and ranged from 58.6% to 96.3%. Sexual maturity was reached at an age of 5 years, which is later than in most large snail species. Our study extends current knowledge on life history of land snails to a rarely studied group dwelling on rock surfaces.
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McKenzie, V. J., W. E. Hall, and R. P. Guralnick. "New Zealand mudsnails (Potamopyrgus antipodarum) in Boulder Creek, Colorado: environmental factors associated with fecundity of a parthenogenic invader." Canadian Journal of Zoology 91, no. 1 (2013): 30–36. http://dx.doi.org/10.1139/cjz-2012-0183.
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New Zealand mudsnails (Potamopyrgus antipodarum (Gray, 1853)) are non-native snails that are increasingly spreading in freshwater systems in North America. Most invasive populations are parthenogenic and threaten native freshwater diversity. We observed variability of P. antipodarum fecundity each month for 16 months at a recently invaded site in Boulder Creek, Colorado. We collected 100 snails each month and dissected them to count embryos in the brood sac. We used a general linear model analysis to examine water-quality variables as predictors of the monthly variability in P. antipodarum fecundity. After dissecting 1600 snails, we observed four male individuals (<1%), brood sizes ranging from 0 to 70 embryos per snail, reproductively mature females at 3.2 mm in length or greater, and a significant relationship between snail length and embryo counts (r2 = 0.38, p < 0.001). The model with the highest level of support for predicting variability in snail fecundity included water temperature, snail shell length, water hardness (calcium carbonate), and nutrient levels (total phosphate) (adjusted r2 = 0.53, p < 0.01). These variables may be important for snail growth and promote increased rates of reproduction in this parthenogenic, invasive snail. These results can further inform efforts to model geographic areas at high risk of P. antipodarum establishment and rapid demographic growth.
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Amobi, Maduabuchi Inwele, and Bede Izuchukwu Ezewudo. "Utilisation of common leafy vegetables in the diets of giant West African snail Archachatina marginata (Swainson, 1821) (Stylommatophora: Achatinidae)." Brazilian Journal of Biological Sciences 6, no. 12 (2019): 181–87. http://dx.doi.org/10.21472/bjbs.061217.
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A study was conducted to evaluate the effects of utilisation of three leafy vegetable diets (bitter leaf Vernonia amygdalina, fluted pumpkin leaf Telfairia occidentalis and pawpaw leaf Carica papaya) on the growth performance of giant West African snail Archachatina marginata. A total of 90 A. marginata were used for the study. 30 snails were also subjected to three different dietary treatments in three replicates of 10 snails per replicate and fed with the fresh leaves of these vegetables over a period of 12 weeks. Results obtained recorded significant differences (P < 0.05) in terms of weight gain, shell length, shell circumference and shell thickness. On the whole, Archachatina marginata fed on fluted pumpkin leaf performed better in terms of mean weight gain when compared with those fed on bitter and pawpaw leaves. On the other hand, snails fed on pawpaw leaf had the best mean shell length gain, mean shell circumference and mean shell thickness when compared with those fed on bitter and fluted pumpkin leaves. The result clearly showed that the tested leafy vegetables can be successfully utilised as diets for rearing of A. marginata. For farmers to achieve better result, the inclusion of fluted pumpkin and pawpaw leaves in the diets of Archachatina marginata is highly recommended in snail rearing businesses.
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Yanes, Yurena, María P. Asta, Miguel Ibáñez, María R. Alonso, and Christopher S. Romanek. "Paleoenvironmental implications of carbon stable isotope composition of land snail tissues." Quaternary Research 80, no. 3 (2013): 596–605. http://dx.doi.org/10.1016/j.yqres.2013.08.010.
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Land snail shell δ13C value is often used as a paleovegetation proxy assuming that snails ingest all plants in relation to their abundance, and that plants are the only source of carbon. However, carbonate ingestion and variable metabolic rates complicate these relationships. We evaluate if live-collected snails from Lanzarote (Canary Islands) reflect the abundance of C3 and CAM plants. Snails were collected on either CAM or C3 plants for isotope analysis of shell and body, and shell size. Respective shell and body δ13C values of snails collected on CAM plants averaged − 8.5 ± 1.7‰ and − 22.8 ± 1.6‰, whereas specimens from C3 plants averaged − 10.1 ± 0.7‰ and − 24.9 ± 1.1‰. A flux balance model suggests snails experienced comparable metabolic rates. A two-source mass balance equation implies that snails consumed ~ 10% of CAM, which agrees with their abundance in the landscape. Snails collected on CAM plant were smaller than those on C3 plants. Conclusively: 1) snails consume CAM plants when they are available; 2) migration of snails among C3 and CAM plants is a common phenomenon; and 3) C3 plants may be a more energetic food for growth than CAM plants. This study shows that shell δ13C values offer approximate estimates of plants in C3–CAM mixed environments.
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Kupfernagel, Sandra, and Bruno Baur. "Sperm utilization in subadult and adult simultaneous hermaphrodite snails mating in the wild." Canadian Journal of Zoology 89, no. 11 (2011): 1041–49. http://dx.doi.org/10.1139/z11-080.
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In species with multiple mating and long-term sperm storage, males are expected to show a preference for mating with virgin and young females to reduce the risk of sperm competition. In various simultaneous hermaphrodite land snail species, sperm production precedes egg production by 2–4 weeks, resulting in a short period of protandric hermaphroditism before shell growth is completed. In a natural population, we collected copulating pairs of the simultaneous hermaphrodite land snail Arianta arbustorum (L., 1758) consisting either of two adults, of two subadults, or of one adult and one subadult snail, and determined the paternity of their hatchlings that emerged from subsequently deposited eggs. Adult snails used sperm received from subadult mating partners for egg fertilization in the same frequency as sperm from adults, indicating that subadult and adult snails do not differ in male function. Furthermore, an unfinished shell is not a reliable indicator for virginity, because 35% of the subadult individuals had already sperm stored from previous mating(s). Compared with adults, young individuals exhibited a lower risk of sperm competition, indicated by a higher last mate sperm precedence. However, subadult snails produced fewer eggs than adult snails, counteracting the evolutionary advantage of preferring a young partner with low sperm competition risk.
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Buwjoom, Tonglian, Buaream Maneewan, Kohsyo Yamauchi, Buncha Pongpisantham, and Koh-en Yamauchi. "Effects of Golden Apple Snail (Pomacea Canaliculata, Lamarck) Shell Particle Size on Growth Performance, Carcass Quality, Bone Strength and Small Intestinal Histology in Thai Native Chickens (Pradu Hang Dum Chiangmai 1)." International Journal of Biology 8, no. 3 (2016): 58. http://dx.doi.org/10.5539/ijb.v8n3p58.
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<p class="1Body">To study whether the particle size of golden apple snail (<em>Pomacea Canaliculata</em>, Lamarck) shell induces negative effects on the growth performance, carcass quality, bone strength and small intestinal histology in Thai native chickens (Pradu Hang Dum Chiangmai 1), 192 chickens, both male and female, were divided into 4 groups with 4 replicates of 12 chickens each at 5 weeks of age. The control group received limestone as a source of calcium. The experimental groups received diets containing golden apple snail shell particles, with sizes ranging from 0:50 to 1:00, from 1.00 to 1.70, and from 1.70 to 2.80 mm as a calcium source. Feed intake and weight were measured weekly, and carcass quality, tibial bone strength and small intestinal histology were observed at 16 weeks of age. The data of growth performance, carcass quality, tibial bone strength and small intestinal histology did not present negative results after feeding any of the golden apple snail shell sizes. On the contrary, a slightly higher weight gain was observed in the group consuming the 1.00 to 1.70 mm snail shell particles during the period from the 13th to the 16th week. Improved carcass quality and pectoralis major and tibial bone strength, as well as significantly increased duodenal villus surface and jejunal crypt cell numbers (p &lt; 0.05) were observed in the group fed the 1.00 to 1.70 mm snail shell particles. These results suggest that golden apple snail shell particles between 1.00 and 1.70 mm can improve growth performance due to hypertrophied intestinal function.</p>
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Hoso, Masaki. "Cost of autotomy drives ontogenetic switching of anti-predator mechanisms under developmental constraints in a land snail." Proceedings of the Royal Society B: Biological Sciences 279, no. 1748 (2012): 4811–16. http://dx.doi.org/10.1098/rspb.2012.1943.
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Autotomy of body parts offers various prey animals immediate benefits of survival in compensation for considerable costs. I found that a land snail Satsuma caliginosa of populations coexisting with a snail-eating snake Pareas iwasakii survived the snake predation by autotomizing its foot, whereas those out of the snake range rarely survived. Regeneration of a lost foot completed in a few weeks but imposed a delay of shell growth. Imprints of autotomy were found in greater than 10 per cent of S. caliginosa in the snake range but in only less than 1 per cent out of it, simultaneously demonstrating intense predation by the snakes and high efficiency of autotomy for surviving snake predation in the wild. However, in experiments, mature S. caliginosa performed autotomy less frequently. Instead of the costly autotomy, they can use defensive denticles on the inside of their shell apertures. Owing to the constraints from the additive growth of shells, most pulmonate snails can produce these denticles only when they have fully grown up. Thus, this developmental constraint limits the availability of the modified aperture, resulting in ontogenetic switching of the alternative defences. This study illustrates how costs of adaptation operate in the evolution of life-history strategies under developmental constraints
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Ovat, I. O., P. E. Esor, and O. I. Iwara. "Effects of different feeding regimes on the growth performance of the giant African land snail Archachatina marginata (Swainson)." Journal of Agriculture, Forestry and the Social Sciences 16, no. 1 (2020): 24–31. http://dx.doi.org/10.4314/joafss.v16i1.3.
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Effects of various feeding regimes on the growth performance of the giant African land snail, Archachatina marginata were studied using one hundred and twenty (120 Juvenile snails) weighing 0.66g +1 per snails for a period of 90 days. The treatments were. T1 -Grower starter, T2 - Grower mash, T3 - cocoyam and cassava leaves and T4 - Ripe pawpaw fruits. The Completely Randomized Design was used with four treatments and each replicated three times. The snails were confined in wooden hutch boxes. Data was collected on weekly body weight feed intake, shell length and shell width. Results obtained showed that snails fed with broiler starter diet (T1) had significantly (P<0.05) higher performance in terms of weight gain, feed intake, shell length and the aperture, while pawpaw fruits T4 recorded the least values. The highest values for feed intake was observed in T1 (135.5g) followed by T2 (78.2g), while the least feed intake was observed in T4 (55.7g). Snails fed with T1 recorded the highest weight gain (60.1g) followed by T2 and T3.The lowest weight gain was obtained in T4 (37.9g). Shell length was highest in T1 (20.7mm), closely followed by T2 (19.2mm). The aperture recorded the highest mean values in T1 (20.1mm). The least operculum was recorded in T4 (12.9mm). Therefore, the broiler starter T1 should be used to feed growing snails to improve their performance.
 Keywords: Snails, Broiler Starter, Grower mesh, Cocoyam leaves, Cassava leaves, Pawpaw fruits, hutch boxes
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Yanes, Yurena, Igor Gutiérrez-Zugasti, and Antonio Delgado. "Late-glacial to Holocene transition in northern Spain deduced from land-snail shelly accumulations." Quaternary Research 78, no. 2 (2012): 373–85. http://dx.doi.org/10.1016/j.yqres.2012.06.008.
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AbstractShells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial–Holocene (~ 12.1–6.3 cal ka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ13C values were − 10.3 ± 1.1‰, − 8.2 ± 2.3‰, and − 7.3 ± 1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ13C values during the late-glacial and some Holocene periods imply higher water stress of C3 plants and/or higher limestone contribution than today. Intrashell δ13C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ18O values were − 1.1 ± 0.7‰, − 0.9 ± 0.8‰ and − 0.1 ± 0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~ 12.1 − 10.9 cal ka BP conditions were drier and became wetter at ~ 8.4 − 6.3 cal ka BP and today. Intrashell δ18O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ18O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.
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Baker, GH. "The Life-History, Population-Dynamics and Polymorphism of Cernuella-Virgata (Mollusca, Helicidae)." Australian Journal of Zoology 36, no. 5 (1988): 497. http://dx.doi.org/10.1071/zo9880497.
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The terrestrial snail, Cernuella virgata, was sampled over 3 years in a permanent pasture and adjacent roadside vegetation at Mt Benson, S.A. C. virgata has an annual life cycle, breeding from autumn to winter. Shell size and the presence of a rib which forms on the inner margin of the shell aperture of large snails during early autumn were used to separate the two cohorts of snails (adults and their young) present during winter. Snails (>6 mm shell diameter) were most abundant in the pasture in spring and in the roadside vegetation in summer. I discuss the importance of dispersal between habitats in contributing to these changes in abundance. C. virgata was aggregated within the pasture at all times of the year, but especially during summer when large proportions of the population (>50%) aestivated on the weed Marrubium vulgare. C. virgata and another abundant snail, Theba pisana, were rarely found together in large numbers in small areas (0.25 m2) within the pasture although both had similar general distributions. Shell sizes and banding patterns of C. virgata varied geographically throughout south-eastern Australia. No correlations between climate and size and banding were found. Size was, however, inversely related to population density. At Mt Benson, unbanded snails were slightly more prevalent in the pasture compared with the roadside vegetation. Shell growth and formation of the marginal rib of C. virgata were advanced by exposure to warm, moist conditions in a glasshouse in summer, but maturation of the albumen gland, and hence reproduction, was not.
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Larsson, J., A. M. Westram, S. Bengmark, T. Lundh, and R. K. Butlin. "A developmentally descriptive method for quantifying shape in gastropod shells." Journal of The Royal Society Interface 17, no. 163 (2020): 20190721. http://dx.doi.org/10.1098/rsif.2019.0721.
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The growth of snail shells can be described by simple mathematical rules. Variation in a few parameters can explain much of the diversity of shell shapes seen in nature. However, empirical studies of gastropod shell shape variation typically use geometric morphometric approaches, which do not capture this growth pattern. We have developed a way to infer a set of developmentally descriptive shape parameters based on three-dimensional logarithmic helicospiral growth and using landmarks from two-dimensional shell images as input. We demonstrate the utility of this approach, and compare it to the geometric morphometric approach, using a large set of Littorina saxatilis shells in which locally adapted populations differ in shape. Our method can be modified easily to make it applicable to a wide range of shell forms, which would allow for investigations of the similarities and differences between and within many different species of gastropods.
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Dododawa, Z., and B. N. Ejidike. "Influence of two management systems on the growth performance of adult African giant land snails (Archachatina marginata)." Journal of Applied and Natural Science 11, no. 2 (2019): 424–28. http://dx.doi.org/10.31018/jans.v11i2.2073.
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African gaint land snails are important as means of alleviating acute protein shortage in Nigeria livestock Industries. The present study aimed to study the influence of intensive and extensive management systems on the growth Performance of adult African Giant Land Snails (Archachatina marginata) was carried out in the wildlife domestication unit of the Department of Forest Resources and Wildlife Management, University of Benin, Benin City, Nigeria. Ninety African giant land snails (A. marginata) of average body weight 160.31g ± 0.38g were used for the study. The snails were grouped into two- Group A and Group B. 45 snails in group A were raised in an intensive system of management while 45 snails in group B were raised in an extensive system of management. The data collected on weight gain, shell length increment and shell width increment during the experiment were subjected to student t-Test at 5% significant level. Results showed that there was a significant difference at (p<0.05) in the weight gain. The intensive management system had a higher weight gain of 128.96g with mean value of 4.96 while the extensive management system had a weight gain of 88.37g with mean value of 3.40. There was no significant difference at (p>0.05) in the shell length increment. The snails in the extensive management system had the higher shell length increment of 5.32cm with mean value of 0.20 while the snails in the intensive management system had a shell length increment of 2.43cm with mean value of 0.09. There was a significant difference at (p<0.05) in the shell width increment. The snails in the extensive management system had the higher shell width increment of 9.31cm with mean value of 0.36 while the snails in the intensive management system had a shell width increment of 4.30cm with mean value of 0.17. The snails in the intensive system had a Feed Conversion Ratio of 5.03. For better growth performance of A. marginata in terms of weight gain, snail farmers should raise their snails in an intensive system of management and formulated diet should be used in feeding the snails along side with natural feed such as leaves and fruits.
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Saha, Chilka, Saida Parveen, Joy Chakraborty, Soujita Pramanik, and Gautam Aditya. "Life table estimates of the invasive snail Physa acuta Draparnaud, 1805, occurring in India." Ekológia (Bratislava) 36, no. 1 (2017): 60–68. http://dx.doi.org/10.1515/eko-2017-0006.
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Abstract The life table characteristics of the invasive snail Physa acuta were assessed in the laboratory using the individuals occurring in a newly colonised area in Burdwan, West Bengal, India. Using the changes in the shell length and the body weight of the snails as surrogate, the population growth of the snails was estimated along with longevity and the fecundity schedule. The cohort of P. acuta lived for a maximum of 22 weeks with a life expectancy (ex) of 7.27 weeks and the age-specific survivorship being 0.825. Increment of the shell length of the snails complied with the von Bertalanffy growth equation, lt = 11.75(1 − exp−0.17(t−0.06)), and the observed and the expected data of the length at time t (lt) did not vary significantly (z score = 0.230; P = 0.818; n=20 pairs). Following attainment of sexual maturity between 28 and 42 days, oviposition continued till 20 weeks time, with 0.1-10 eggs laid by each individual. The eggs present per capsule remained between 01 and 11, whilst the net reproductive rate (R0), intrinsic rate of increase (rm) and the finite rate of increase (λ) were 116.07, 0.1 and 1.11, respectively. The observations are similar to those made earlier on the same species but from African and South American continents. The results of the present observation are pioneer in providing the initial studies about the life history of the invasive snail P. acuta in Indian context. Using the present information as a basis, further studies including long-term population monitoring should be initiated to understand the effects of the invasive snail P. acuta in the freshwater ecosystem of West Bengal, India.
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Ademolu, K. O., A. B. Idowu, and O. A. Jayeola. "Changes in Haemolymph Biochemical values during different growth phases in African Giant Land Snail (Archachatina Marginata) Swainson." Nigerian Journal of Animal Production 36, no. 1 (2021): 161–66. http://dx.doi.org/10.51791/njap.v36i1.1200.
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The impact of growth phases on the haemolympy biochemical value of African giant land snail Archachatina marginata was studied. The growth phases were: snailet, juvenile and Adult based on the number of whorls on the shell and weight of the snails. Highest concentration of glucose and lipids were recorded at the juvenile phase (40.20mg/dl), while least values for glucose (20.00mg/dl) and lipids (37.80mg/dl)were recorded during snailer and adult phases respectively. A progressive increase in the concentration of protein was observed as the snails moved from snailetphase to adult phase, hence snails in adult phase had highest concentration of protein in their haemolymph. Growth phases significantly (p<0.05) affected the haemolymph mineral composition of the snails, juvenile phase had the highest values in ca2+,PO4+ and Na+, while the adult phase recorded the least concentration in ca2+, Na amd cl-2. Juvenile growth phase of A. marginata thus has better haemolymph biochemical values than both snailet and adult growth phases.
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Miura, Osamu, Armand M. Kuris, Mark E. Torchin, Ryan F. Hechinger, and Satoshi Chiba. "Parasites alter host phenotype and may create a new ecological niche for snail hosts." Proceedings of the Royal Society B: Biological Sciences 273, no. 1592 (2006): 1323–28. http://dx.doi.org/10.1098/rspb.2005.3451.
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By modifying the behaviour and morphology of hosts, parasites may strongly impact host individuals, populations and communities. We examined the effects of a common trematode parasite on its snail host, Batillaria cumingi (Batillariidae). This widespread snail is usually the most abundant invertebrate in salt marshes and mudflats of the northeastern coast of Asia. More than half (52.6%, n =1360) of the snails in our study were infected. We found that snails living in the lower intertidal zone were markedly larger and exhibited different shell morphology than those in the upper intertidal zone. The large morphotypes in the lower tidal zone were all infected by the trematode, Cercaria batillariae (Heterophyidae). We used a transplant experiment, a mark-and-recapture experiment and stable carbon isotope ratios to reveal that snails infected by the trematode move to the lower intertidal zone, resume growth after maturation and consume different resources. By simultaneously changing the morphology and behaviour of individual hosts, this parasite alters the demographics and potentially modifies resource use of the snail population. Since trematodes are common and often abundant in marine and freshwater habitats throughout the world, their effects potentially alter food webs in many systems.
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Abiona, John Adesanya, Taiwo Gabriel Olaoye, Monsuru Oladimeji Abioja, and Okanlawon Mohammed Onagbesan. "Effect of zinc oxide on liveweight, reproductive organ dimensions and spermatozoa production of Archachatina marginata during dry season." Agricultura Tropica et Subtropica 51, no. 4 (2018): 147–54. http://dx.doi.org/10.2478/ats-2018-0017.
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Abstract Demand for Giant African Land Snail in Nigeria is so high such that it is very difficult to meet up with the supply as a protein source. However, during dry season, production at intensive level is often challenged with decline in growth and reproduction despite interventions to boost production. This study therefore evaluates the effect of zinc oxide on liveweight, reproductive organ dimensions and spermatozoa production of Giant African Land Snail (Archachatina marginata) during dry season. Thirty-two (32) snails with an average weight of 100 – 180 g were used for this experiment. The snails were allotted to four different feeding treatments which included concentrate diet only, concentrate +10 mg/kg of zinc oxide, concentrate +15 mg/kg of zinc oxide and concentrate +20 mg/kg of zinc oxide, respectively. Each treatment contained eight replicates. After nine weeks, five snails were selected from each treatment and dissected. Variables monitored were: weekly weight gain, shell circumference, shell length and shell diameter. Other reproductive data collected after dissections were: organ weight, reproductive tract weight, albumen weight, ovo-testis weight, gonado-somatic index (GSI) and spermatozoa concentration. The result showed that dietary zinc oxide significantly (P < 0.001) influenced feed intake, shell parameters, organ weight ovo-testis weight, albumen weight, gonado-somatic index, reproductive tract weight and spermatozoa concentration. Snailsfed zinc oxide supplemented diet had better shell measurements, organ weight, ovo-testis weight, albumen weight, gonadosomatic index and reproductive tract weight. Considering spermatozoa concentration, 10 mg/kg of zinc oxide inclusion into concentrate diet gave the highest concentration. The results of the present study showed that dietary zinc oxide positively influenced feed intake, shell measurements, organ weight, ovo-testis and albumen weight. Similarly, gonado-somatic index and spermatozoa production were also positively influenced. Therefore, 10 mg/kg inclusion of zinc oxide is recommended for better reproductive tract development, and spermatozoa production at the desirable economic level during the dry season production of Archachatina marginata.
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Ugwuowo, L. C., and N. H. Anyaokei. "Tolerance of African giant land snails (Archachatina marginata) to varying levels of table Salt." Nigerian Journal of Animal Production 47, no. 4 (2020): 37–43. http://dx.doi.org/10.51791/njap.v47i4.106.
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An experiment was conducted to determine the growth response of African giant land snail Archachatina marginata fed diets containing different levels of sodium chloride. One hundred and twenty snails were subjected to four dietary treatments of T1, T2, T3 and T4 with 0%, 0.25%, 0.5% and 0.75% sodium chloride respectively. The treatments were replicated thrice with 10 snails per replicate. The measured parameters included weight gain, feed intake, shell length, shell circumference and shell thickness. Feed cost, cost of feed per kg weight gain and feed conversion ratio were also calculated. Results showed that there were significant differences (p < 0.05) in average daily weight gain, average daily feed intake, feed conversion ratio, feed cost and shell thickness but there were no significant differences (p > 0.05) in cost of feed per kg weight gain, shell length and shell circumference in the snails fed the treatment diets. Treatment 2 had the highest average daily weight gain (0.07±0.01), average daily feed intake (0.91±0.08) and feed cost (7.19±0.64) but the lowest feed conversion ratio (13.15±61.76) while treatment 1 had the lowest average daily weight gain (0.04±0.01), average daily feed intake (0.70±0.20) and feed cost (5.54±0.18) but the highest feed conversion ratio (15.86±0.5). This shows that inclusion of sodium chloride above 0.25% in the diet of Archachatina marginata affects both the feed intake and weight gain of the snails.
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Nahid, SAA, PJG Henriksson, and MA Wahab. "Value-chain analysis of freshwater apple snail (Pila globosa) used for on-farm feeds in the freshwater prawn farming sector in Bangladesh." International Journal of Agricultural Research, Innovation and Technology 3, no. 2 (2014): 22–30. http://dx.doi.org/10.3329/ijarit.v3i2.17840.
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Growth of the freshwater prawn (Macrobrachium rosenbergii) sector in Bangladesh since 1970s has been supported by natural availability of freshwater apple snail (Pila globosa), used for on-farm prawn feeds. The present study identified the current configuration of the value-chain benefits and constraints of freshwater apple snail in south-western Bangladesh in August 2011, based upon Rapid Market Appraisal (RMA) approach. The site of snail collection was Chanda Beel in Gopalganj district, while trading, processing and final consumption was represented by Rayer Mahal Bazar in Khulna district. There were seven different nodes recognized throughout the value chain. Snail marketing was identified as a seasonal business and took place during June to November each year. Between 1995 and 2011 the price of whole snail, meat and shell has increased by 800%, 325% and 315%, respectively. The abundance of snail had been reduced and its demand has increased due to the expansion of the prawn farming industry. Prawn farmers preferred snail meat due to its low cost (US$ 0.21 kg-1) as a source of protein compared to commercial prawn feed (US$ 0.41 kg-1). Snail harvesting and processing were considered as additional livelihood options for the poor, where 60% of the labour involved in snail harvesting were women, and 95% the de-shelling workforce. Induced breeding in captivity and sustainable management in nature as well as development of commercial production of apple snails might reduce the pressure on ecosystems and positively contributed to the continued expansion of freshwater prawn farming in Bangladesh. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17840 Int. J. Agril. Res. Innov. & Tech. 3 (2): 22-30, December, 2013
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Gorbushin, Alexander M. "The Enigma of Mud Snail Shell Growth: Asymmetrical Competition or Character Displacement?" Oikos 77, no. 1 (1996): 85. http://dx.doi.org/10.2307/3545588.
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Odunaiya, O., and A. A. Akinyemi. "Performance of two snail species – Archachatina marginata (S) and Achatina achatina (I) reared under the same management practices." Nigerian Journal of Animal Production 35, no. 2 (2021): 224–29. http://dx.doi.org/10.51791/njap.v35i2.2473.
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The performance and carcass analysis of two popular snail species - Archatina marginata (S) and Achatina achatina (L) commonly reared in West Africa were evaluated from day old to six (6) months of age under the same housing and dietary conditions in a complete randomized design with two (2) treatments, replicated thrice with sixty (60) snails per treatment. The study revealed that at day old treatment 1 (T1) had the higher live weight of 4.03g, while treatment 2 (T2) had 0.31g which showed a statistical significant difference at P<0.05. The shell length and shell width of the hatchlings also showed statistical significant difference (P<0.05) between the two treatments. The mean feed intake (g/day) for T1 was 2.89 and 1.96 for T2. Higher mortality (8.33%) was recorded in T2. T2 was also found to be the better converter of feed to edible meat with feed conversion ratio of 7.26 to 72.3 recorded in T1. The higher dressing out percentage (40.14) was recorded in T1. The result showed that snails generally have slow growth. T1 was found to grow faster than T2 hence it is recommended to the populace because it has higher potential to meet animal protein supply than T2. Research on improvement and nutrition of snails should therefore be encouraged.
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Páll-Gergely, Barna, Fred Naggs, and Takahiro Asami. "Novel shell device for gas exchange in an operculate land snail." Biology Letters 12, no. 7 (2016): 20160151. http://dx.doi.org/10.1098/rsbl.2016.0151.
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The operculum of terrestrial snails tightly seals the shell aperture providing protection from predators and body-water loss. To allow respiration with a closed operculum, operculate land snails repeatedly evolved shell devices such as tubes or channels that open to the air. In all Asian members of the Alycaeidae, an externally closed tube lies along the suture behind the aperture that possesses a small internal opening into the last whorl at the tube's anterior end. However, this structure presents a paradox: how is gas exchanged through an externally closed tube? Here we show that many microtunnels open into the tube and run beneath radial ribs along the growth line of the last whorl in Alycaeus conformis . These tunnels open to the outside of the shell surface near the umbilicus. Examination under high magnification revealed that the outermost shell layer forms these tunnels only in the whorl range beneath the sutural tube. Each tunnel ( ca 16 µm diameter) is far narrower than any known metazoan parasite. These findings support our hypothesis that the externally closed sutural tube functions with microtunnels as a specialized apparatus for predator-free gas exchange with minimal water loss when the operculum seals the aperture.
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Puizina, Jasna, Sanja Puljas, Željana Fredotović, Ivica Šamanić, and Grgur Pleslić. "Phylogenetic Relationships among Populations of the Vineyard Snail Cernuella virgata (Da Costa, 1778)." ISRN Zoology 2013 (September 12, 2013): 1–9. http://dx.doi.org/10.1155/2013/638325.
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Cernuella virgata (Da Costa, 1778) (Mollusca: Hygromiidae), commonly known as the “vineyard snail,” is endemic species in Mediterranean and Western Europe including the British Isles, but in the Eastern USA and Australia it represents an introduced invasive species. The present work examines the genetic variability and phylogenetic relationships among the four populations of this land snail sampled along the east Adriatic region of Croatia using mitochondrial markers (partial 16S rDNA and COI gene) in addition to traditional methods of shell’s shape analysis. All the three molecular-phylogenetic approaches (median joining haplotype network analysis and Bayesian analysis, as well as maximum likelihood analysis) revealed two-three major subnetworks for both 16S rDNA and COI, with a clear distinction between south Adriatic haplotypes (Pisak) and north Adriatic haplotypes (Krk and Cres). The population from Karlobag was comprised of both north and south haplotypes, thus representing a putative contact zone between these two groups. The morphometric analysis showed that individuals from Cres island population were statistically significantly wider and higher than individuals from Pisak population. Analysis of the SW/SH ratio and the relationship between shell width and shell height showed no differences in shell growth between the two examined populations, indicating equal shell growth and shape, which gives the possibility that differences in size of individuals between those two populations could be influenced by biotic (physiological) or abiotic (environmental) factors. This study represents the first analysis of genetic variability and relatedness among native populations of C. virgata.
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Leise, Esther M., Jeremy T. Washburn, Joshua Long, Brandi Bridgewater, and Nishant Shah. "Acidic Seawater can Promote Larval Metamorphosis in the Marine Mud Snail, Nassarius obsoletus." Journal of North Carolina Academy of Science 130, no. 2 (2014): 65–71. http://dx.doi.org/10.7572/2167-5880-130.2.65.
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Abstract Elevated levels of atmospheric CO2 have had the unintended effect of acidifying the world's oceans by at least 0.1 pH unit since the beginning of the industrial revolution. Current models of the effects of continued CO2 release anticipate a further increase in ocean acidity by 0.14 to 0.4 pH units by the end of this century. Numerous marine organisms with calcareous shells or exoskeletons are expected to undergo deleterious effects, including shell or exoskeletal dissolution or calcification with increased metabolic costs. While many studies have documented potential effects of ocean acidity on adult calcareous organisms, less work has focused on embryonic or developmental changes. Alterations in ocean biochemistry can affect metabolic processes beyond calcification, and our investigations into the development of the local intertidal mudsnail, Nassarius obsoletus, led us to hypothesize that rising ocean acidity would increase incidents of larval shell decalcification, decrease larval growth rates, and induce precocious metamorphosis. As an initial study of potential effects of future acidic conditions on larval N. obsoletus, we raised larvae in seawater adjusted to lower than normal pH levels with hydrochloric acid (HCl), measured larval growth every 5 days in 15 randomly selected individuals from each culture, and conducted experiments on larval metamorphosis in physiologically competent larvae. We found no major trend in growth patterns of larvae from pH 8.2 to 7.7. However, results from a number of pharmacological experiments demonstrated that larvae grown in acidic conditions metamorphose more readily than controls. Our investigations are far from a definitive exploration of the effects of oceanic acidity on the development of this marine mollusc, but our data suggest that key developmental processes in marine invertebrates may be influenced in unexpected ways by continued climatic changes.
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Łozicki, Andrzej, Tomasz Niemiec, Robert Pietrasik, Sylwester Pawęta, Anna Rygało-Galewska, and Klara Zglińska. "The Effect of Ag Nanoparticles and Multimicrobial Preparation as Factors Stabilizing the Microbiological Homeostasis of Feed Tables for Cornu aspersum (Müller) Snails on Snail Growth and Quality Parameters of Carcasses and Shells." Animals 10, no. 12 (2020): 2260. http://dx.doi.org/10.3390/ani10122260.
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The aim of this research was to evaluate the effect of Ag nanoparticles (nano-Ag) used in the paint covering feed tables or a multimicrobial preparation applied to feed tables on the microbiological composition of the feed table environment, the growth and mortality of snails, and selected parameters for assessing the quality of carcasses and snail shells. The research was carried out in a farm of Cornu aspersum (Müller) snails. In the control (K) group, paint without nano-Ag was used. In two other groups (N-Ag and N-Ag + effective microorganisms (EM)), the feed tables were covered with the same paint as in the control group but with the addition of 100 mg/L of nano-Ag it (N-Ag group). Additionally, multimicrobial preparation (EM Bokashi®) at a concentration of 10% was spread on the tables in the N-Ag + EM group. In the last group (EM), the feed tables were covered with paint without nano-Ag, and only multimicrobial preparation was applied at a concentration of 10%. During the tests, the body weight of snails was measured three times, and swab samples were taken from the feed tables for the examination of microbiological composition. At the end of the experiment, the snails were killed, and the weight of the carcass and the size of the shell were measured. The content of Ag and the degree of lipid oxidation (thiobarbituric acid reactive substances (TBARS)) in the carcasses were analyzed, and the content of Ca and the crushing strength of the shells were determined. In the N-Ag and N-Ag + EM groups, a significant reduction in the total number of bacteria, fecal streptococci, and Escherichia coli was found, while there was also a reduction in mold and fungi in the N-Ag + EM and EM groups. In the K and EM groups, the mortality of animals was higher than in the nano-Ag groups. In subsequent weight checks, the highest body weight was found in the EM group and the lowest in the N-Ag and N-Ag + EM groups. In addition, the carcass weight and shell size in the N-Ag group was significantly lower compared to the K and EM groups. In the N-Ag and N-Ag + EM groups, a higher Ag content in the carcasses and a greater degree of lipid peroxidation were found. The Ca content of the shells was the highest in the N-Ag group, and the hardness of shells was the highest in the N-Ag and N-Ag + EM groups.
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Omole, A. J. "Performance and Carcass Analysis of Growing Snails Fed Calopogonium mucunoides (Calopo) And Pueraria phaseoloides (Kudzupuero)." Nigerian Journal of Animal Production 37, no. 1 (2021): 85–90. http://dx.doi.org/10.51791/njap.v37i1.673.
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An experiment was carried out to determine the effect of feeding growing snails with two different leguminous plants, Calopogonium muculoides, Pueraria phaseoloides, using pawpaw (Carica papaya) leaf as control. A total of 72 growing snails (Archachatina marginata) of mean weight 74.73/3.5g were used for the feeding trial. The snails were randomly alloted into 3 different groups and each group was replicated 4 times with 6 snails per replicate in a completely randomized design. Snails in T1 were fed pawpaw leaf (control), while snails in T2 were fed Calopogolium muculoides. Parameters measured were feed intake, weight gain, shell length and width and feed conversion ratio. The feeding trial lasted for 12 weeks. The results on growth performances reveal that the highest feed intake was recorded in snails fed pawpaw leaf (PL) which was similar to the those fed Pueraria phaseoloids (PP), while the lowest feed intake was recorded in snail fed with Calopognium muculoids (CM). The highest weight gain was also recorded in snails fed with pawpaw leaf and Peuraria phaseoloids (PP) than those fed Calopognium muculoides (CM). In conclusion, Pueraria phaseoloids could be used as substitute for pawpaw leaf.
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Vignoles, P., D. Rondelaud, and G. Dreyfuss. "Paramphistomum daubneyi: production dynamics and infectivity of metacercariae originating from snails dissected at regular intervals." Journal of Helminthology 82, no. 2 (2008): 175–80. http://dx.doi.org/10.1017/s0022149x0893652x.
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AbstractExperimental infections of Galba truncatula with Paramphistomum daubneyi were carried out at 24°C to study the dynamics of larval development in snails dissected at regular intervals and to determine if metacercarial production might be improved. When the shell height of snails (4, 5, 6 or 7 mm) at exposure increased (experiment A), the total number of metacercariae was significantly higher in the 6- and 7-mm snails than in the other two groups, and the differentiation period was shortened (the first cercariae encysted at day 35 post-exposure (p.e.) instead of day 40 in the 4- and 5-mm groups). When the number of miracidia (two, three or five) for each 6-mm high G. truncatula increased (experiment B), a significant decrease of snail survival at day 30 p.e., a significant augmentation of prevalence, and a significant increase of metacercarial production were noted. In the two- and three-miracidium groups, the number of metacercariae was close to that found in the 6-mm snails from experiment 1, whereas they showed slower growth from day 45 to day 65 in the five-miracidium group. In the two groups of lambs infected with metacercariae encysted at days 45 or 60 p.e., no difference in the numbers of adult worms was noted. In contrast, in the case of 35-day encysted larvae, the number of adult worms was clearly lower. Snail dissection allowed higher metacercarial production, a saving of 12–15 days at 24°C to obtain these larvae, and a substantial decrease of their cost price for commercial production.
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Henny, Henny, Efawani Efawani, and Eddiwan Eddiwan. "MORPHOMETRIC, MERISTIC, AND GROWTH PATTERNS OF THE STROMBUS TURTURELLA FROM THE DOMPAK ISLAND COASTAL AREA, TANJUNGPINANG KEPULAUAN RIAU." Asian Journal of Aquatic Sciences 2, no. 1 (2020): 57–64. http://dx.doi.org/10.31258/ajoas.2.1.57-64.
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Strombus turturella is a type of gastropods that live in the shallow coastal area of the Dompak Island. A research aims to understand the morphometrical, meristical characteristics and growth patterns of S. turturella from the Dompak Island was conducted in June-July 2018. The number of snail sampled was 400, with 46.98-83.07 TL mm and 13-46 grams BW. There were six morphological characteristics measured, there were total length, shell length, aperture length, shell width, shell depth and lip thickness, and there was one meristical characteristic count, namely the number of spire. Results shown that there are 5 morphometrical characteristic differences in males and females. Total length of male is longer than that of the female. While other characteristics, such as the shell length and aperture of the females were longer, the shell was wider, deeper and the lip was thicker than those of the males. The number of spire was 4-9 in males and 4-8 in females. The lenghweight relationship shown that the growth of males and females is allometric negative (b=0.503).
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Okocha, C. N., and D. N. Onunkwo. "Influence of various feeding regimes on the performance of Archachatina marginata snail." Nigerian Journal of Animal Production 45, no. 2 (2020): 209–14. http://dx.doi.org/10.51791/njap.v45i2.479.
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This study was to evaluate the growth response of Archachatina marginata as influenced by four natural diets: Pawpaw (Carica papaya) cocoyam (Colocasia esculenta), cocoyam (Xanthosoma sagittifolium), and cassava (Manihot esculenta) leaves and growers mash (a compounded ration). One hundred and twenty (120) grower snails (Archachatina marginata) were purchased from a farm in Ibadan, Oyo State. Data were collected on the growth parameters (weight, length and circumference of shell of the snails arranged in a Completely Randomized Design and replicated three (3) times. The results showed that pawpaw (Carica papaya) recorded the highest mean in all the parameters measured and throughout the duration of the experiment. Cocoyam (Colocasia esculenta) leaf had a better mean than the Cassava (Manihot esculenta) leaves in terms of weight gained whereas the reverse is the case in terms of length and circumference of shell. Pawpaw (Carica papaya) is therefore, recommended to both local and small scale farmers in Abia State and in Nigeria for feeding their snails and cocoyam (Colocasia esculenta) leaves and growers mash as an alternate feed.
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Wirtz Ocana, Sabine, Patrick Meidl, Danielle Bonfils, and Michael Taborsky. "Y-linked Mendelian inheritance of giant and dwarf male morphs in shell-brooding cichlids." Proceedings of the Royal Society B: Biological Sciences 281, no. 1794 (2014): 20140253. http://dx.doi.org/10.1098/rspb.2014.0253.
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Behavioural variation among conspecifics is typically contingent on individual state or environmental conditions. Sex-specific genetic polymorphisms are enigmatic because they lack conditionality, and genes causing adaptive trait variation in one sex may reduce Darwinian fitness in the other. One way to avoid such genetic antagonism is to control sex-specific traits by inheritance via sex chromosomes. Here, controlled laboratory crossings suggest that in snail-brooding cichlid fish a single locus, two-allele polymorphism located on a sex-linked chromosome of heterogametic males generates an extreme reproductive dimorphism. Both natural and sexual selection are responsible for exceptionally large body size of bourgeois males, creating a niche for a miniature male phenotype to evolve. This extreme intrasexual dimorphism results from selection on opposite size thresholds caused by a single ecological factor, empty snail shells used as breeding substrate. Paternity analyses reveal that in the field parasitic dwarf males sire the majority of offspring in direct sperm competition with large nest owners exceeding their size more than 40 times. Apparently, use of empty snail shells as breeding substrate and single locus sex-linked inheritance of growth are the major ecological and genetic mechanisms responsible for the extreme intrasexual diversity observed in Lamprologus callipterus .
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Saura, Maria, Maria José Rivas, Angel P. Diz, Armando Caballero, and Emilio Rolan-Alvarez. "Dietary effects on shell growth and shape in an intertidal marine snail, Littorina saxatilis." Journal of Molluscan Studies 78, no. 2 (2012): 213–16. http://dx.doi.org/10.1093/mollus/eys004.
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Hu, Zongfu, Qing Tong, Jie Chang, et al. "Gut bacterial communities in the freshwater snail Planorbella trivolvis and their modification by a non-herbivorous diet." PeerJ 9 (February 12, 2021): e10716. http://dx.doi.org/10.7717/peerj.10716.
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The freshwater pulmonate snail Planorbella trivolvis is a common species in various bodies of water but is not native to China. Planorbella trivolvis usually live on diets with high fiber content, such as water grasses, algae and fallen leaves. These snails can attach to the wall of a water tank or to water grass and can be transported overseas to China through the ornamental fish trade. There are few studies investigating the intestinal microbiota of freshwater snails. In this study, using culture-independent molecular analysis, we assessed for the first time the complexity of bacterial communities in the intestines of reared snails. The intestinal microbiota in the snails fed different diets, that is, herbivorous feed (HV) with high cellulose and non-herbivorous feed (NHV) with low cellulose, were analyzed by Illumina sequencing. The results showed that the NHV-based diet significantly increased the body mass, shell diameter and specific growth rate of the snails after 60 days of rearing (P < 0.05). Histological experiments showed that the fat droplets in the epithelium columnar cells of the intestines of the NHV snails increased, and the cilia on these cells fell off. The sequencing results identified 486 and 195 OTUs in HV and NHV, respectively. Lots of bacteria were not reported previously in snails. The intestinal microbiota diversity index (Shannon, Simpson, Ace and Chao) in the NHV snails was significantly lower than that in the HV snails. The gut microbiota in the HV snails were predominantly Proteobacteria (52.97%) and Bacteroidetes (28.75%), while the gut microbiota in NHV snails were predominantly Proteobacteria (95.23%). At the genus level, Cloacibacterium (24.60%), Pseudomonas (4.47%), OM6ON (6.12%), and Rhodobacter (5.79%) were observed to be abundant in HV snails. However, Aeromonas (85.4%) was determined to be predominant in NHV snails. Functional prediction of the gut microbiome in snails by PICRUSt demonstrated a significant difference between the two groups, and the HV snails exhibited higher lignocellulose enzyme activity than did the NHV snails. This study represents a first step in characterizing the gut microbiota of the freshwater snail. Most of these microbes can process plant biomass and digest cellulose and lignocellulose, and the enzymes of these bacteria may have potential biotechnological applications in a variety of industrial processes.
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Schram, Julie B., Kathryn M. Schoenrock, James B. McClintock, Charles D. Amsler, and Robert A. Angus. "Testing Antarctic resilience: the effects of elevated seawater temperature and decreased pH on two gastropod species." ICES Journal of Marine Science 73, no. 3 (2015): 739–52. http://dx.doi.org/10.1093/icesjms/fsv233.
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Abstract Ocean acidification has been hypothesized to increase stress and decrease shell calcification in gastropods, particularly in cold water habitats like the western Antarctic Peninsula (WAP). There is limited information on how calcified marine benthic invertebrates in this region will respond to these rapidly changing conditions. The present study investigated the effects of elevated seawater temperature and decreased pH on growth (wet mass and shell morphometrics), net calcification, and proximate body composition (protein and lipid) of body tissues in two common benthic gastropods. Individuals of the limpet Nacella concinna and the snail Margarella antarctica collected from the WAP were exposed to seawater in one of four treatment combinations: current ambient conditions (1.5°C, pH 8.0), near-future decreased pH (1.5°C, pH 7.8), near-future elevated temperature (3.5°C, pH 8.0), or combination of decreased pH and elevated temperature (3.5°C, pH 7.8). Following a 6-week exposure, limpets showed no temperature or pH effects on whole body mass or net calcification. Despite no significant differences in whole body mass, the shell length and width of limpets at elevated temperature tended to grow less than those at ambient temperature. There was a significant interaction between the sex of limpets and pH. There were no significant temperature or pH effects on growth, net calcification, shell morphologies, or proximate body composition of snails. Our findings suggest that both gastropod species demonstrate resilience to initial exposure to temperature and pH changes predicted to occur over the next several hundred years globally and perhaps sooner along the WAP. Despite few significant impacts of elevated temperature or decreased pH, any response to either abiotic variable in species with relatively slow growth and long lifespan is of note. In particular, we detected modest impacts of reduced pH on lipid allocation in the reproductive organs of the limpet N. concinna that warrants further study.
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Baur, A., and B. Baur. "Altitudinal variation in size and composition of eggs in the land snail Arianta arbustorum." Canadian Journal of Zoology 76, no. 11 (1998): 2067–74. http://dx.doi.org/10.1139/z98-145.
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Egg size and egg provisioning are crucial for the survival of offspring in invertebrates without postlaying egg care. The effects of elevation and size of the mother on egg size and on nitrogen and carbon concentrations in eggs were examined in eight populations of the land snail Arianta arbustorum over an altitudinal gradient from 370 to 2340 m in Switzerland. The dry mass of single eggs ranged from 1.48 to 2.79 mg and decreased with increasing altitude. Adult snail size (shell volume) also decreased with increasing elevation as did clutch size and reproductive investment (clutch size x egg dry mass) of mothers. Hatching success of eggs varied among populations, but showed no altitudinal pattern. When differences in parental shell size were taken into account, correlations between altitude and egg size, clutch size, and reproductive investment disappeared. Thus, the altitudinal decreases in egg size, clutch size, and reproductive investment were mainly due to smaller snail sizes at higher elevations. The nitrogen concentration in eggs ranged from 3.4 to 4.5% and decreased with increasing elevation. In contrast to egg and clutch size, the altitudinal variation in nitrogen concentration of eggs cannot be explained by differences in snail size. The carbon concentration in eggs ranged from 31.1 to 33.1%, but showed no altitudinal variation. Nitrogen and carbon concentrations in the eggshell and egg fluid in eggs from four populations were examined separately. The nitrogen concentration in the eggshell ranged from 0.7 to 1.8% and was lower than that of the egg fluid (5.1-5.8%). Similarly, the carbon concentration in the eggshell was lower (20.2-22.8%) than that in the egg fluid (35.8-0.2%). Interpopulation differences in egg composition may affect growth, size, and survival of hatchlings and the extent of egg cannibalism in A. arbustorum.
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Gefaell, J., N. Varela, and E. Rolán-Alvarez. "Comparing shape along growth trajectories in two marine snail ecotypes of Littorina saxatilis: a test of evolution by paedomorphosis." Journal of Molluscan Studies 86, no. 4 (2020): 382–88. http://dx.doi.org/10.1093/mollus/eyaa020.
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ABSTRACT Two sympatric ecotypes (‘crab’ and ‘wave’) of Littorina saxatilis are adapted to different microhabitats. It has been claimed, based on the comparison of proteomic differentiation across ontogeny, that the wave ecotype may have evolved by paedomorphosis from an ancestor more similar to the crab ecotype. Here, we test the paedomorphosis hypothesis at a morphological level by comparing crab and wave specimens from two localities using the pattern of shell shape differentiation across ontogeny. The results obtained show a pattern of shell shape differentiation similar to the one observed in previous proteomic studies, but such a pattern could be caused by different modes of evolution, and not necessarily by paedomorphosis. This study emphasizes that in addition to studying the pattern of differentiation, the direction of the evolutionary change across ontogeny has to be analysed before conclusions can be drawn on particular developmental modes of evolution.
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Okocha, C. N., and D. N. Onunkwo. "Comparative study of three species of giant African land snail." Nigerian Journal of Animal Production 45, no. 2 (2020): 77–87. http://dx.doi.org/10.51791/njap.v45i2.478.
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A comparative study was carried out on three breeds of snails in South Eastern Nigeria to assess their growth performance and body morphology. The three breeds used were A. Fulica, A. achatina and A. marginata. Four experimental diets were formulated to contain Concentrate + Pawpaw (Diet I), Concentrate + Moringa oleifera (Diet II), Concentrate + Moringa oleifera + African spinach + Amaranthus hybridus (Diet III) and Concentrate + Moringa oleifera + Amaranthus spinosus (Diet IV). Fifteen 6-month old growing snails of each breed were assigned per dietary treatment and each dietary treatment was replicated three times to contain five snails per replicate, given a total of one hundred and eighty snails. The experiment involved a 3 x 4 factorial experiment in a Completely Randomized Design (CRD). Feed and water were given ad libitum throughout the duration of the experiment which lasted (56 days). Parameters measured were body parameters which include body weight, body width, body length, aperture length and aperture width; growth performance parameters obtained were initial weight, final weight, average weekly weight gain, average weekly feed intake and feed conversion ratio. The results showed that the A. achatina and A. marginata similarly recorded higher values in body parameters than the A. fulica. The A. marginata however was longer (12.69 cm) than the 8.95 and 12.32 cm recorded for A. fulica and A. marginata gain was only influenced by interaction effect of the breed x diet. The A. marginata and A. fulica revealed higher foot weight 58.81% and 57.59% respectively in relation to their live weight, which was associated with lower % shell weight (17.17 and 22.33% respectively), whereas, the higher shell weight (36.18%). The highest foot weight (57.50%) was observed in snails fed diet I, associated with relatively high live weight and highly reduced offal weight, which makes it comparatively better in improving carcass. Based on overall interaction effects, diet I is recommended for A. fulica, while diet III for A. marginata and diet II for A. marginata. The A. marginata performed better than the A. achatina and A. fulica in body size (body length) and foot weight, thus recommended.
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Albuquerque, FS, MC Peso-Aguiar, MJT Assunção-Albuquerque, and L. Gálvez. "Do climate variables and human density affect Achatina fulica (Bowditch) (Gastropoda: Pulmonata) shell length, total weight and condition factor?" Brazilian Journal of Biology 69, no. 3 (2009): 879–85. http://dx.doi.org/10.1590/s1519-69842009000400016.
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The length-weight relationship and condition factor have been broadly investigated in snails to obtain the index of physical condition of populations and evaluate habitat quality. Herein, our goal was to describe the best predictors that explain Achatina fulica biometrical parameters and well being in a recently introduced population. From November 2001 to November 2002, monthly snail samples were collected in Lauro de Freitas City, Bahia, Brazil. Shell length and total weight were measured in the laboratory and the potential curve and condition factor were calculated. Five environmental variables were considered: temperature range, mean temperature, humidity, precipitation and human density. Multiple regressions were used to generate models including multiple predictors, via model selection approach, and then ranked with AIC criteria. Partial regressions were used to obtain the separated coefficients of determination of climate and human density models. A total of 1.460 individuals were collected, presenting a shell length range between 4.8 to 102.5 mm (mean: 42.18 mm). The relationship between total length and total weight revealed that Achatina fulica presented a negative allometric growth. Simple regression indicated that humidity has a significant influence on A. fulica total length and weight. Temperature range was the main variable that influenced the condition factor. Multiple regressions showed that climatic and human variables explain a small proportion of the variance in shell length and total weight, but may explain up to 55.7% of the condition factor variance. Consequently, we believe that the well being and biometric parameters of A. fulica can be influenced by climatic and human density factors.
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Ireland, M. P. "The effect of dietary calcium on growth, shell thickness and tissue calcium distribution in the snail Achatina fulica." Comparative Biochemistry and Physiology Part A: Physiology 98, no. 1 (1991): 111–16. http://dx.doi.org/10.1016/0300-9629(91)90587-3.
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Glass, Nancy H., and Philip C. Darby. "The effect of calcium and pH on Florida apple snail, Pomacea paludosa (Gastropoda: Ampullariidae), shell growth and crush weight." Aquatic Ecology 43, no. 4 (2008): 1085–93. http://dx.doi.org/10.1007/s10452-008-9226-3.
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Journal, Baghdad Science. "An Ecological Study of the Brown Garden snail Cornu aspersum (Müller, 1774) from selected habitats in Jadiriya in Baghdad vicinity." Baghdad Science Journal 7, no. 1 (2010): 223–32. http://dx.doi.org/10.21123/bsj.7.1.223-232.
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The present study is considered a pioneer investigation that deal with the terrestrial brown garden snail Cornu aspersum (Müller), in Iraq. Cornu aspersum however is considered an exotic species in many parts of the world ,The species is most probably infiltrates with plants transferred from one place to another. The species has gained importance in many ways. Nutritionally, the species is consumed as food item in many countries, but in other cases it is considered as pest for the damage it causes when feeding on valuable plant shoots. It also has medical importance for its role and ability in healing wounds, burns and remedy of other skin problems. This snail species however may act as a vector for some parasitic nematodes that cause serious diseases. The species is also important in scientific research, usually referred to as ‘ecological indicator’ employed in environmental pollution problems such as the one caused by heavy metals. A great deal of research on this species has been carried out in different parts of the world, however, in Iraq, the scientific attention given to land snails in general and to Cornu aspersum in particular is rare and may be negligible in comparison with the research carried out on aquatic Mollusca species. A total of 1880 individuals of Cornu aspersum were collected from all sampling sites. The study was carried out for the period November 2007 to November 2008 on three sites within the Jadiriya district in Baghdad.. Growth, size classes and shell dimensions of Cornu aspersum populations, and their relationship with major environmental factors; ambient temperature; soil pH, moisture, texture; and the soil content of organic matter have been also investigated. Identification of the species was confirmed by the British Natural History Museum.The data were analyzed by means of standard statistical procedures.
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Reineskog, Michael. "Aluminium inhibition of calcium carbonate crystal growth: In vitro studies related to shell-repair in the snail Helix pomatia L." Comparative Biochemistry and Physiology Part C: Comparative Pharmacology 96, no. 2 (1990): 353–56. http://dx.doi.org/10.1016/0742-8413(90)90020-a.
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Ningrum, Riska Surya, Aisyah Ramadani, Reny Rosalina, Desy Yustiyani, and Rio Altha Reyzando. "PREPARATION AND ANTIFUNGAL ACTIVITIES OF CHITOSAN FROM APPLE-SNAIL (Pila ampullacea) SHELLS AS PRESERVING AGENT FOR POSTHARVEST PODANG MANGO (Mangifera indica L.) cv Podang." Indonesian Journal of Applied Research (IJAR) 2, no. 2 (2021): 66–78. http://dx.doi.org/10.30997/ijar.v2i2.120.
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Podang mango, an endemic mango from Kediri, has a short post-harvest shelf life that accelerates by physiological factors and pathogenic fungal contamination. Chitosan reported as an active compound for coating. The apple-snail was reported to contain chitosan in its shell. The purposes of this study are to synthesis chitosan from Pila ampullacea, examine anti-fungal activities to Fusarium oxysporum and Aspergillus ochraceus, and verify the effect of chitosan coating on shelf life and quality of Podang mango. The effect of chitosan coating on fruit quality was analyzed using three treatments which were negative control, chitosan, and chitosan-gelatin with 3 replications. The parameters measured were color, texture, aroma, water content, vitamin C, and weight loss. Results showed that chitosan synthesized from P. ampullacea had 53.56 degrees of deacetylation. Antifungal activity test of chitosan 2% had the highest inhibitory activity against F.oxysporum and A.ochraceus growth with 14.46 mm and 10.33 mm inhibition zone. Coating with chitosan statistically affected fruit quality for 14 days of storage (sig <0.05). Chitosan-gelatin coating is the best treatment in reducing weight loss (8.97%), maintain aroma (sweet fragrance), texture (soft), water content (84%), and vitamin C (0.182%), while the color (reddish yellow) was more influenced by Chitosan coating. Chitosan coated with gelatin is recommended for application on Podang mangoes.
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Mozzer, L. R., A. L. Coaglio, R. M. Dracz, V. M. A. Ribeiro, and W. S. Lima. "The development of Angiostrongylus vasorum (Baillet, 1866) in the freshwater snail Pomacea canaliculata (Lamarck, 1822)." Journal of Helminthology 89, no. 6 (2014): 755–59. http://dx.doi.org/10.1017/s0022149x14000856.
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AbstractAngiostrongylus vasorum is a parasitic nematode that infects the heart and pulmonary artery and its branches of domestic and wild canids. The parasite can use several species of terrestrial and aquatic molluscs as intermediate hosts, although susceptibility varies. Pomacea canaliculata is a mollusc found in lakes, swamps and rivers in South America. In this study, we evaluated the susceptibility, parasite growth, oviposition and larval development of 282 P. canaliculata infected with 500 A. vasorum first-instar larvae (L1). From day 5 post-infection (pi) to day 30 pi, seven specimens per day were sacrificed to recover the larval instars. We compared 50 egg masses from infected and uninfected molluscs to determine the number of eggs per clutch, the hatching rate and the growth of the molluscs. The percentage of recovered larvae ranged from 39.17% to 67.5%. First-stage larvae (L1) were found until day 19 pi, second-stage larvae (L2) were found from days 11 to 25 pi, and third-stage larvae (L3) were recovered only after day 19 pi. Infected snails exhibited the most eggs during spawning, although the rate of hatching and shell size were lower in the infected snails compared with controls. This is the first report of an experimental infection of P. canaliculata with A. vasorum, and the results confirm the non-specificity of the nematode in relation to the intermediate host and indicate the importance of epidemiological surveys of this parasite and mollusc.
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Lombardo, Paola, Francesco Paolo Miccoli, Anna Cichy, Anna Stanicka, and Elżbieta Żbikowska. "No effects of waterproof marking on the behaviour and growth of Physa acuta Draparnaud, 1805 (Gastropoda: Hygrophila: Physidae) in the laboratory." Folia Malacologica 29, no. 2 (2021): 121–31. http://dx.doi.org/10.12657/folmal.029.013.
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Physa acuta Draparnaud, 1805 is one of the most common freshwater gastropod species, with worldwide distribution. It is an effective periphyton grazer and a potential keystone species in shallow-water systems, where it can boost macrophyte well-being and thus help maintain high water clarity even in nutrient-rich habitats. P. acuta also has been extensively studied in ecotoxicological and behavioural investigations. Such investigations may require observations on individual snails. A method to distinguish individual snails in small-scale experiments is marking their shells with paint dots. However, such marking must not influence snail behaviour (nutritional, reproductive, respiratory, etc.) or growth to avoid confounding effects. Earlier investigations point to no or very limited effects of marking on aquatic and terrestrial snail survival, behaviour, and growth. We tested whether marking could affect the behaviour (as snail activity) and growth of P. acuta using a waterproof, oil-based, non-toxic, fine-point car-body paint marker. Snails were divided into a “marked” and an “unmarked” (control) group of ten snails each in an eight-day experiment. The marking had no effect on the snail activity or growth. The snails survived the experiment and produced egg clutches well beyond the eight-day period. The marking persisted without fading during and beyond the experimental period. Our results support earlier findings that the use of oil-based, non-toxic markers can assist in carrying out reliable observations on individual snails, including the small-bodied P. acuta. Combinations of two dots of different colours allow simultaneous observations on a high number of replicate individuals.