Achatina Research Articles

Investigation of Immune Responses in Giant African Snail, Achatina immaculata, against a Two-Round Lipopolysaccharide Challenge.

As one of the 100 most-threatening invasive alien species, the giant African snail (Achatina immaculata) has successfully invaded and established itself in most areas of southern China. Protection against recurrent pathogen infections is vital to biological invasion. Enhanced immune protection has been previously found in other invertebrates, but not in the unique immune system of the giant African snail. In the present study, the survival rate of the giant African snail was recorded following a second infection with lethal doses of Escherichia coli after a previous first injection using lipopolysaccharide (LPS), and the mechanism of immune enhancement was investigated by examining the cellular and transcriptomic response of the giant African snail after two successive stimuli using LPS. Snails injected first with LPS, sterilized physiologic (0.9%) saline (SPS), phosphate-buffered saline (PBS) or untreated (Blank) were rechallenged at 7d with E. coli (Ec), and were named as LPS + Ec, SPS + Ec, PBS + Ec, Ec, and Blank. The log-rank test shows the survival rate of the LPS + Ec group as significantly higher than that of other control groups after the second injection (p < 0.05). By performing cell counting and BrdU labeling on newly generated circulating hemocytes, we found that the total hemocyte count (THC) and the ratio of BrdU-positive cells to total cells increased significantly after primary stimulation with LPS and that they further increased after the second challenge. Then, caspase-3 of apoptosis protease and two antioxidant enzyme activities (CAT and SOD) increased significantly after infection, and were significantly higher in the second response than they had been in the first round. Moreover, transcriptome analysis results showed that 84 differentially expressed genes (DEGs) were expressed at higher levels in both the resting and activating states after the second immune response compared to the levels observed after the first challenge. Among them, some DEGs, including Toll-like receptor 4 (TLR4) and its downstream signaling molecules, were verified using qRT-PCR and were consistent with the transcriptome assay results. Based on gene expression levels, we proposed that these genes related to the TLR signaling cascade participate in enhanced immune protection. All results provide evidence that enhanced immune protection exists in the giant African snail.

Anti-feedant and Molluscicidal Activities of Selected Spices Against Achatina fulica (Gastropoda: Achatinidae)

The application of biopesticides is progressively encouraged for its advantages associated with environmental safety and high biodegradability. The objectives of this study were to compare the phytochemical constituents, anti-feedant, and molluscicidal activities of spices against the giant African land snail, Achatina fulica. The spices evaluated were clove (Syzygium aromaticum), cinnamon (Cinnamomum verum), black pepper (Piper nigrum), cumin (Cuminum cyminum) and coriander (Coriandrum sativum). Phytochemical constituents of spices were screened by qualitative standard protocols. Anti-feedant activity was investigated by the leaf disc no-choice bioassay method and molluscicidal activity was evaluated by a 72-h contact toxicity test. The phytochemical screening showed positive results for tannins, saponins, alkaloids, flavonoids, terpenoids, and phenols in clove, cinnamon, cumin and coriander ethanolic extracts whereas only tannins, alkaloids and terpenoids were found in the black pepper ethanolic extract. The leaf disc no-choice bioassay revealed that all spices demonstrated anti-feedant activity (p&lt;0.05, compared to control). However, only clove (85.33±3.09%), cinnamon (72.35±3.41%) and coriander (81.54±3.88%) ethanolic extracts showed high feeding inhibition activity, whereas black pepper (68.85±3.22%) and cumin (68.96±3.12%) had moderate anti-feedant activity. In the contact toxicity test, clove ethanolic extract (52.67±1.53%) showed moderate molluscicidal activity, meanwhile cinnamon (19.34±2.08%), black pepper (16.65±1.15%), cumin (18.96±1.42%) and coriander (22.67±1.37%) demonstrated low molluscicidal activity. In conclusion, all spices tested in this study showed the presence of important secondary metabolites that contribute to anti-feedant and molluscicidal activities at differening levels.

Understanding Snail Mucus Biosynthesis and Shell Biomineralisation through Genomic Data Mining of the Reconstructed Carbohydrate and Glycan Metabolic Pathways of the Giant African Snail (Achatina fulica).

The giant African snail (Order Stylommatophora: Family Achatinidae), Achatina fulica (Bowdich, 1822), is the most significant and invasive land snail pest. The ecological adaptability of this snail involves high growth rate, reproductive capacity, and shell and mucus production, driven by several biochemical processes and metabolism. The available genomic information for A. fulica provides excellent opportunities to hinder the underlying processes of adaptation, mainly carbohydrate and glycan metabolic pathways toward the shell and mucus formation. The authors analysed the 1.78 Gb draft genomic contigs of A. fulica to identify enzyme-coding genes and reconstruct biochemical pathways related to the carbohydrate and glycan metabolism using a designed bioinformatic workflow. Three hundred and seventy-seven enzymes involved in the carbohydrate and glycan metabolic pathways were identified based on the KEGG pathway reference in combination with protein sequence comparison, structural analysis, and manual curation. Fourteen complete pathways of carbohydrate metabolism and seven complete pathways of glycan metabolism supported the nutrient acquisition and production of the mucus proteoglycans. Increased copy numbers of amylases, cellulases, and chitinases highlighted the snail advantage in food consumption and fast growth rate. The ascorbate biosynthesis pathway identified from the carbohydrate metabolic pathways of A. fulica was involved in the shell biomineralisation process in association with the collagen protein network, carbonic anhydrases, tyrosinases, and several ion transporters. Thus, our bioinformatic workflow was able to reconstruct carbohydrate metabolism, mucus biosynthesis, and shell biomineralisation pathways from the A. fulica genome and transcriptome data. These findings could reveal several evolutionary advantages of the A. fulica snail, and will benefit the discovery of valuable enzymes for industrial and medical applications.

First Report of Giant African Snail (Lissachatina fulica) in a Protected Area of the Cottian Alps, Northwest Italy

The Giant African snail (Lissachatina fulica) is listed among the top 100 worst invasive alien species. Native to East Africa, it has been introduced voluntarily or accidentally into more than 50 countries, where it impacts negatively on biodiversity, ecosystems, agriculture, and public health. Here we describe for the first time the finding of a specimen of L. fulica in a protected area of the Cottian Alps (Avigliana Lakes Nature Park, northwest Italy). The snail underwent morphometric analysis and species identification. Given its reproductive characteristics (i.e., hermaphroditism with self-fertilization), it poses a potential threat to the biodiversity of the area and is a vector of zoonotic parasites for humans and animals. Health monitoring of specimens found in the wild and those kept as pets is of crucial importance, as is the establishment of monitoring plans in these areas.

Purification and characterisation of heparin-like sulfated polysaccharides with potent anti-SARS-CoV-2 activity from snail mucus of Achatina fulica

Heparin-like sulfated polysaccharide, acharan sulfate, was purified from the mucus of an African giant snail with unique sulfated glycosaminoglycans (GAGs). This study reported on finding novel and safe heparin resources from Achatina fulica for further use as well as easy isolation and purification of the active fraction from the initial raw material. Its structure was characterised by a strong-anion exchange combined with high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectroscopy. The results indicated that the potential acharan sulfate fraction is a glycosaminoglycan composed of several repeating disaccharide units, namely, of →4)−α−IdoA(2S)(1→4)−α−GlcNAc/GlcNAc(6S)/GlcNSO3(6S)(1→, and hence, presents heterogeneity regarding negative net charge density. Furthermore, the heparinase digests inhibit the binding of SARS-CoV-2 spike protein to the ACE2 receptor. In summary, the acharan sulfate presented in this work has shown its great potential for application in the preparation of sulfated polysaccharides as an alternative to heparin with important biological activity.

Children's Relationships with a Non-Vertebrate Animal: The Case of a Giant African Land Snail (Achatina fulica) at School.

Employing living animals in educational settings is popular and may assist learning. Human-animal relationships are considered fundamental for the effects of animal-assisted interventions (AAI) on successful learning. Key studies on AAI emphasize dogs, or other large-brained vertebrates, while AAI with non-vertebrate species is a yet rather unexplored field. However, bringing non-vertebrate species to school has ethical and practical advantages. In an exploratory study, we tested whether seven-years-old children would form caregiving relationships with a Giant African land snail (Achatina fulica). Prior to the survey, the snail had been kept inside a terrarium in the classroom for seven months. We employed a questionnaire for measuring children's pet attachment to assess the children's relationships with the snail. The observed relationship scores with the snail were intermediate to high and did not differ from same-aged children's attachment scores with their dogs, cats, and rabbits. No differences due to gender were observed. Children potentially developed caregiving attitudes and empathy towards the snail, and thus, the presented results indicate potential benefits from employing a non-vertebrate species in educational settings, as well as for animal-assisted therapy. The specific features of A. fulica are discussed in the frame of human-animal interactions, learning, and anthropomorphism.

High lability of global niche and range in the Giant African Snail (Lissachatina fulica): Small niche expansions resulting in large range shifts

As a major source of global change, biological invasions have received increasing attention in past decades. Niche and range dynamics of alien invasive species provide essential evidence for understanding mechanisms underlying biological invasions. However, to our knowledge few relevant studies on mollusks have been reported. Here, from the perspective of climatic suitability, we investigated niche and range shifts of the Giant African Snail (Lissachatina fulica), one of the world’s most invasive mollusks. We observed that, compared with its native counterpart, this invasive snail could survive in environments with wider temperature ranges. The invasive snail showed a wider niche breadth and larger potential range than its native counterpart, and occupied different niche and range positions, indicating its high lability in terms of niche and range. This invasive Giant African Snail did not conform to the niche and range conservatism hypotheses, probably due to the influence of human introductions and niche releasing. Given that large shifts in range size can result from small niche expansions, making niche shifts a more important indicator for biological invasion assessments than range shifts. While most invasive species show low lability in niche space, highly labile niche was observed in the Giant African Snail, indicating that strategies to prevent biological invasions by this invasive mollusk should be prioritized. Our study, to certain extent, could further our understanding on the niche shifts and range dynamics between the invasive mollusks and their native counterparts.

Effects and Cost-Benefit of Low and High Protein Levels in Snail Diets with Constant Levels of Energy and Calcium

Snails are invertebrates with soft segmented shells. Snail farming is still at the infant stage compared to other farming enterprises because of limited information on the nutrient requirement of the animal. Therefore, a 12-week study was conducted to determine the effect of snails’ diets containing low and high Crude protein (CP) levels with constant level of energy and calcium on the growth performance of African giant land snail Archachatina marginata. In a completely randomized design, a total of 120 snails of the same weight and breed were randomly allotted to five (5) different dietary treatments: PR1 (20% CP), PR2 (22% CP), PR3 (24% CP), PR4 (26% CP) and PR5 (28% CP) with constant energy (2.6 Mcal/kg Metabolizable Energy) and calcium level. The snails were placed in 12 experimental compartments each measuring 0.5x 0.5m2. Results revealed that the body weight gain, feed intake, cost of feed per kg weight gain and dressing percentage yield was significantly (p &lt; 0.05) higher at the 28% CP. Furthermore, results showed significant (P&lt; 0.05) interactions between protein across the treatments performance indices, shell length, shell width, feed cost per kg weight gain and dressing percentage yield. Feed intake decreased significantly (p &lt; 0.05) at 20% CP level while the FCR values decreased (p &lt; 0.05) at 28% CP level. Shell length, width and thickness was enhanced (p &lt; 0.05) at 20% CP level. Also, the Feed cost per kg weight gain was observed to be significantly (p &lt; 0.05) reduced at the 24% CP. The results obtained in the present study showed that the dietary protein of 24% CP, with constant energy of 2.6Mcal/kg ME is optimally suitable for the growth of African giant land snails Archachatina marginata at reduced cost.

Increasing Antimicrobial Resistance and Potential Human Bacterial Pathogens in an Invasive Land Snail Driven by Urbanization

Our understanding of the role urbanization has in augmenting invasive species that carry human bacterial pathogens and antimicrobial resistance (AMR) remains poorly understood. Here, we investigated the gut bacterial communities, antibiotic resistance genes (ARGs) and potential antibiotic-resistant pathogens in giant African snails (Achatina fulica) collected across an urbanization gradient in Xiamen, China (n = 108). There was a lack of correlation between the microbial profiles of giant African snails and the soils of their habitats, and the resistome and human-associated bacteria were significantly higher than those of native snails as well as soils. We observed high diversity (601 ARG subtypes) and abundance (1.5 copies per 16S rRNA gene) of giant African snail gut resistome. Moreover, giant African snails in more urban areas had greater diversity and abundance of high-risk ARGs and potential human bacterial pathogens (e.g., ESKAPE pathogens). We highlight that urbanization significantly impacted the gut microbiomes and resistomes of these invasive snails, indicating that they harbor greater biological contaminants such as ARGs and potential human bacterial pathogens than native snails and soils. This study advances our understanding of the effect of urbanization on human bacterial pathogens and AMR in a problematic invasive snail and should help combat risks associated with invasive species under the One Health framework.

Examining the Predatory Relationship Between the Indigenous Firefly (Aspisoma ignitum) and the Invasive Giant African Snail (Achatina fulica) in Trinidad, West Indies

The current study investigates the predatory relationship between the firefly larvae (Aspisoma ignitum) and the giant African snail (Achatina fulica). The principal objective of this study was to examine the specific predator responsiveness of the firefly larvae against the giant African snails under experimental conditions. This was evaluated using two (2) treatments T1 and T2. T1 investigated giant African snail neonates of size 0.5 cm with a larva to snail ratio of 1:5. In T2, larvae to snail ratio of 3:1 was investigated using 2 cm giant African snail neonates. Control treatments were included in the experimental design with the absence of the larvae. Each treatment was replicated five (5) times. There were 100 % mortality effects for T1 and T2. Commonalities existed in both the spatial and the temporal characteristics to possibly consider the firefly larvae as an idealistic and highly compatible predator for the giant African snail neonates. Ecological engineering strategies to encourage the presence of the firefly will aid in suppressing the giant African snail population. The study concludes that the firefly larvae can be a possible predator for the control of the giant African snail once the firefly populations are encouraged in both crop and non-crop spaces.

Purification and biochemical characterization of phytase from Bacillus cereus isolated from gastrointestinal tract of African giant snail (Achatina fulica).

Phytases are specialized enzymes meant for phytic acid degradation. They possess ability to prevent phytic acid indigestion, including its attendant environmental pollution. This study was aimed at investigating biochemical properties of purified phytase of B. cereus isolated from Achatina fulica. Phytase produced from Bacillus cereus that exhibited optimal phytate degrading-ability of all the bacteria isolated was purified in a three-step purification. The biochemical properties of the purified enzyme were also determined. The phytase homogeny of approximately 45kDa exhibited 12.8-purification fold and 1.6% yield with optima phytate degrading efficiency and maximum stability at pH 7 and 50°C. Remaining activity of 52 and 47% obtained between 60 and 70°C after 2h further established thermostability of the purified phytase. Mg2+ and Zn2+ enhanced phytate hydrolysis by the enzyme, while Na+ showed mild inhibition but Hg2+ severely inhibited the enzymatic activity. Km and Vmax were estimated to be 0.11mM and 55.6μmol/min/mL, displaying enzyme-high substrate affinity and catalytic efficiency, respectively. Phytase purified from Bacillus cereus, isolated from African giant snails, has shown excellent characteristics suitable for phytic acid hydrolysis and could be employed in industrial and biotechnological applications.

Conceptualising an ethno‐mimetic model for effective buildings' end‐of‐life waste management: A Nigerian exemplar

AbstractIn most developed nations, a formal recycling industry oversees the management of solid waste. The opposite happens to be the case in underdeveloped nations wherein, the informal recycling sector has assumed such functions. The informal methods used in Nigeria for managing buildings' end‐of‐life situations has shown in many ways to be compliant with the sustainability goal since they provide an excellent example of how the waste hierarchy may evolve independently, with little or no assistance from policy and regulatory bodies. The purpose of this study is to conceptualise the processes through which salvaged materials from buildings in Kano State, Nigeria is processed in a step‐by‐step manner, ensuring that least amounts of materials end up in a landfill. Adopting a qualitative research design to achieve the study's aim, this study engaged 19 purposively selected experts through semi‐structured interviews in the city of Kano, Nigeria. The collected data was analysed using thematic analysis. Using the biomorphic adaptation of an African snail's shell, the study's findings led to the development of a conceptual model that depicts the actual scenario of handling demolition waste in Nigeria while highlighting the important elements and the inherent interactions among them. Based on these findings, the study recommends that the identified limitations in the Nigerian construction industry be addressed for the purposes of practice improvement and emergence of a comprehensive framework for the sustainable handling of building demolition waste (BDW).

Evaluating different diets on the growth performance of mud crab (Scylla serrata)

The purpose of this study was to assess the potential of natural feeds for the sustainable grow-out aquaculture of mud crabs as an alternative to commercially available mud crab feeds. This study employed a completely randomized design that includes five feed treatments including trash fish, African land snail, horn snail, edible frog, and mud snail. There were three replicates for each treatment with three cages each located in a concrete tank with an area of 12m2. Each cage contained one lean crab. The crabs were fed twice a day, at 7 a.m. and 8 p.m. with an amount adjusted to 7% of the crab's body weight. After the first 21 days, all the crabs were harvested by draining out the tank water and the pincers of the crab were tied with a string to enable handling. The results showed that the highest growth performance in weight gain and condition factor was seen in African land snail feed with a feed conversion ratio of 1.38, indicating a high-quality feed. It also showed an impressive ROI of 96.8% which can be confirmed that this kind of feed might be a viable mud crab feed for both commercial scale and industry.

Use of plant extracts to control activities of the invasive giant African land snail Achatina fulica

Giant African land snails (Achatina fulica; GALS) are a highly invasive herbivore and pose serious threats to native species and that could disrupt ecosystems. Various botanical extracts have been used as molluscicides to control mollusks for pest management. We aimed to identify the effects of neem (Azadirachta indica) and titepati (Artemisia vulgaris) to reduce GALS activities and survival using solutions of fresh neem leaf and titepati leaf, bark, and root. We found a fast movement in the GALS only in the extraction groups while the lethargic movement was lower in mulching method. A significant association of control groups with different extraction groups along with mulching treatment (p&lt;0.05) however, no differences were observed among different extractions at 2.5% and 5% concentrations. Among the treatments, Neem leaf at 5% concentration was found to be effective as it helped immobilize the samples after ten days whilst other treatments required minimum 14 days to be effective. We recommend further studies of titepati and neem as control agents to reduce crop and vegetable damage from GALS.

Evidence for large land snail cooking and consumption at Border Cave c. 170–70 ka ago. Implications for the evolution of human diet and social behaviour

Fragments of land snail (Achatinidae) shell were found at Border Cave in varying proportions in all archaeological members, with the exception of the oldest members 5 WA and 6 BS (>227,000 years ago). They were recovered in relatively high frequencies in Members 4 WA, 4 BS, 1 RGBS and 3 WA. The shell fragments present a range of colours from lustrous beige to brown and matt grey. The colour variability can occur when shell is heated. This possibility was explored here through experimental heating of giant land snail shell fragments (Achatinidae, Metachatina kraussi - brown lipped agate snail) in a muffle furnace from 200 to 550 °C for different lengths of time. Colour change, weight loss, and shattering of the heated samples were recorded. Transformation of aragonite into calcite and the occurrence of organic material was investigated by means of Infrared and Raman spectroscopy. Scanning electron microscopy was also used on selected specimens to help identify heat-induced transformation as opposed to taphonomic alteration. The identification on archaeological fragments of features produced by experimentally heating shells at high temperatures or for long periods has led us, after discarding alternative hypotheses, to conclude that large African land snails were systematically brought to the site by humans, roasted and consumed, starting from 170,000 years ago and, more intensively between 160,000 and 70,000 years ago. Border Cave is at present the earliest known site at which this subsistence strategy is recorded. Previous research has shown that charred whole rhizomes and fragments of edible Hypoxis angustifolia were also brought to Border Cave to be roasted and shared at the site. Thus, evidence from both the rhizomes and snails in Border Cave supports an interpretation of members of the group provisioning others at a home base, which gives us a glimpse into the complex social life of early Homo sapiens.

An A to Z of enhancements: G is for growing

A focus on plants has given children experiences of growing butterflies and African land snails. By Amy Jackson

Modeling and optimization of transesterification of rubber seed oil using sulfonated CaO derived from giant African land snail (Achatina fulica) catalyst by response surface methodology

Rubber seed oil (RSO) is an abundance of low-cost non-edible vegetable oil and an attractive resource for biodiesel production through transesterification. The study aims to model and optimize the transesterification of RSO to biodiesel using sulfonated CaO derived from snail shells as a bifunctional heterogeneous catalyst. We prepared the raw snail shell (RSS) catalyst by calcination and sulfonated it to produce an acid-activated snail shell (AASS) catalyst. We used the central composite design (CCD) of the response surface methodology (RSM) to model and optimize the transesterification process. The X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller method (BET) were used to characterize RSS and AASS catalysts.The results show that CaO (95.6%) is the major component of RSS. The maximum biodiesel yield of 97.6% was obtained at a 12:1 methanol to oil molar ratio, 80 °C reaction temperature, 2.5 h reaction time, and 2.5 wt% catalyst loading with a quadratic regression model. The recyclability of the catalyst shows six runs without an appreciable decrease in biodiesel yield. The AASS catalyst can perform excellently as a bifunctional solid acid heterogeneous catalyst, and the fuel properties of the biodiesel produced compare favorably with American society for testing and materials (ASTM D6751) and European standard methods (EN 14214) standards.

Ultrasound and autoclave-deacetylated Achatina fulica shell chitosan: Characterisation and effect on tomato and cucumber fruit qualities during storage

Chitosan from African giant snail (Achatina fulica) shells derived through autoclave- (SSCA) or ultrasound-assisted (SSCU) deacetylation was characterised and evaluated for quality and shelf life of tomatoes and cucumbers over 10 days of ambient (26 ± 2 °C) and refrigerated (4 ± 2 °C) storage. A 64.03 and 54.41% deacetylation degrees were achieved for SSCA and SSCU, respectively with the SEM showing uniform surface morphologies. Moisture loss in tomatoes was effectively moderated by SSCA and SSCU treatments as depicted by higher weight retention (93.65% and 81.80%) compared to untreated samples (58.52%) after 10 days of refrigerated storage. Autoclave-derived chitosan significantly retained colour of tomato and cucumber. Ascorbic acid retentions were 88.76% and 87.34%, and 86.40% and 77.01% for SSCA and SSCU-treated tomatoes at ambient and refrigerated storage, respectively. Yeast and mould growths were completely inhibited for 10 days of refrigerated storage. Chitosan treatment enhanced quality and shelf life of tomatoes and cucumbers in the order SSCA > SSCU > control.

Distribution patterns of established alien land snail species in the Western Palaearctic Region

Established alien land snail species that were introduced into the Western Palaearctic Region from other regions and their spread in the Western Palaearctic are reviewed. Thirteen of the 22 species came from North America, three from Sub-Saharan Africa, two from the Australian region, three probably from the Oriental Region and one from South America. The establishment of outdoor populations of these species was usually first seen at the western or southern rims of the Western Palearctic. Within Europe, the alien species usually spread from south to north and from west to east. The latitudinal ranges of the alien species significantly increased with increasing time since the first record of introduction to the Western Palearctic. The latitudinal mid-points of the Western Palaearctic and native ranges of the species are significantly correlated when one outlier is omitted. There is a general trend of poleward shifts of the ranges of the species in the Western Palaearctic compared to their native ranges. There are three reasons for these shifts: (1) the northward expansion of some species in Western Europe facilitated by the oceanic climate, (2) the impediment to the colonisation of southern latitudes in the Western Palaearctic due to their aridity and (3) the establishment of tropical species in the Mediterranean and the Middle East. Most of the species are small, not carnivorous and unlikely to cause serious ecological or economic damage. In contrast, the recently introduced large veronicellid slugs from Sub-Saharan Africa and the giant African snail Lissachatina fulica could cause economic damage in irrigated agricultural areas or greenhouses in the Mediterranean and the Middle East.

Shell shape as a potential predictor of age class in the invasive snailLissachatina fulica

ABSTRACTUnderstanding the life-history traits of invasive species can increase the effectiveness of eradication efforts and decrease costs. In the giant African snail Lissachatina fulica, one of the 100 worst invasive species on the planet, age structure can be an important indicator of invasiveness. Here, we associated variation in snail size with variation in weight and shell shape, in an effort to better understand the growth pattern in this species. Our study involved two components: we estimated the allometric relationship between weight and length in a natural population and monitored developmental variation in snail shape, weight, length and nutritional condition (condition factor) in a lab population. The weight and length growth patterns of the lab population were estimated independently using exponential regressions based on weekly measurements; shell shape was quantified using geometric morphometrics. In both populations, we found negative allometry between weight and length, suggesting that snail shells tend to elongate during growth. Geometric morphometrics confirmed this pattern and revealed that the change from a rounded to an elongated shell shape does not occur at a constant pace but during a specific growth interval (i.e. at a shell length of 55–65 mm), which is described in the literature as the size when the animal becomes hermaphroditic. Future studies should test whether the shape change reported here corresponds to the transition to the hermaphrodite age class, and with this in mind, we provide two simple morphological indexes that allow us to characterize shell shape as rounded or elongated. If shell size and shape are indicative of the transition to the hermaphroditism, then our findings can help to place individuals of L. fulica into appropriate age classes, and this will represent a useful baseline for development of eradication policies.