Behavior Of Snails Research Articles

Influence of a Nitric Oxide Donor on Electrical Characteristics of the Premotor Interneurons of Terrestrial Snails

It has been found that application of a nitric oxide donor—the sodium nitroprusside—causes the hyperpolarization shift of the membrane potential of the premotor interneurons of defensive behavior of terrestrial snails. It is assumed that the response of a neuron to NO depends on its location in the neural network.

β-III tubulin modulates the behavior of Snail overexpressed during the epithelial-to-mesenchymal transition in colon cancer cells

Class III β-tubulin (TUBB3) is a marker of drug resistance expressed in a variety of solid tumors. Originally, it was described as an important element of chemoresistance to taxanes. Recent studies have revealed that TUBB3 is also involved in an adaptive response to a microenvironmental stressor, e.g. low oxygen levels and poor nutrient supply in some solid tumors, independently of the microtubule targeting agent. Furthermore, it has been demonstrated that TUBB3 is a marker of biological aggressiveness associated with modulation of metastatic abilities in colon cancer. The epithelial-to-mesenchymal transition (EMT) is a basic cellular process by which epithelial cells lose their epithelial behavior and become invasive cells involved in cancer metastasis. Snail is a zinc-finger transcription factor which is able to induce EMT through the repression of E-cadherin expression. In the presented studies we focused on the analysis of the TUBB3 role in EMT-induced colon adenocarcinoma cell lines HT-29 and LS180. We observed a positive correlation between Snail presence and TUBB3 upregulation in tested adenocarcinoma cell lines. The cellular and behavioral analysis revealed for the first time that elevated TUBB3 level is functionally linked to increased cell migration and invasive capability of EMT induced cells. Additionally, the post-transcriptional modifications (phosphorylation, glycosylation) appear to regulate the cellular localization of TUBB3 and its phosphorylation, observed in cytoskeleton, is probably involved in cell motility modulation.

Intraguild predation by shore crabs affects mortality, behavior, growth, and densities of California horn snails

AbstractThe California horn snail, Cerithideopsis californica, and the shore crabs, Pachygrapsus crassipes and Hemigrapsus oregonensis, compete for epibenthic microalgae, but the crabs also eat snails. Such intraguild predation is common in nature, despite models predicting instability. Using a series of manipulations and field surveys, we examined intraguild predation from several angles, including the effects of stage‐dependent predation along with direct consumptive and nonconsumptive predator effects on intraguild prey. In the laboratory, we found that crabs fed on macroalgae, snail eggs, and snails, and the size of consumed snails increased with predator crab size. In field experiments, snails grew less in the presence of crabs partially because snails behaved differently and were buried in the sediment (nonconsumptive effects). Consistent with these results, crab and snail abundances were negatively correlated in three field surveys conducted at three different spatial scales in estuaries of California, Baja California, and Baja California Sur: (1) among 61 sites spanning multiple habitat types in three estuaries, (2) among the habitats of 13 estuaries, and (3) among 34 tidal creek sites in one estuary. These results indicate that shore crabs are intraguild predators on California horn snails that affect snail populations via predation and by influencing snail behavior and performance.

Nicotine inhibits potassium currents in Aplysia bag cell neurons.

Acetylcholine and the archetypal cholinergic agonist, nicotine, are typically associated with the opening of ionotropic receptors. In the bag cell neurons, which govern the reproductive behavior of the marine snail, Aplysia californica, there are two cholinergic responses: a relatively large acetylcholine-induced current and a relatively small nicotine-induced current. Both currents are readily apparent at resting membrane potential and result from the opening of distinct ionotropic receptors. We now report a separate current response elicited by applying nicotine to cultured bag cell neurons under whole cell voltage-clamp. This current was ostensibly inward, best resolved at depolarized voltages, presented a noncooperative dose-response with a half-maximal concentration near 1.5 mM, and associated with a decrease in membrane conductance. The unique nicotine-evoked response was not altered by intracellular perfusion with the G protein blocker GDPβS or exposure to classical nicotinic antagonists but was occluded by replacing intracellular K(+) with Cs(+) Consistent with an underlying mechanism of direct inhibition of one or more K(+) channels, nicotine was found to rapidly reduce the fast-inactivating A-type K(+) current as well as both components of the delayed-rectifier K(+) current. Finally, nicotine increased bag cell neuron excitability, which manifested as reduction in spike threshold, greater action potential height and width, and markedly more spiking to continuous depolarizing current injection. In contrast to conventional transient activation of nicotinic ionotropic receptors, block of K(+) channels could represent a nonstandard means for nicotine to profoundly alter the electrical properties of neurons over prolonged periods of time.

Previous motor activity affects the transition from uncertainty to decision making in snails.

One of the most widely accepted benefits of enhanced physical activity is an improvement in the symptoms of depression, including the facilitation of decision making. Up until now, these effects have been shown in rodents and humans only. Little is known about their evolutionary origin or biological basis, and the underlying cellular mechanisms also remain relatively elusive. Here, we demonstrate for the first time that preceding motor activity accelerates decision making in an invertebrate, the pond snail Lymnaea stagnalis To investigate decision making in a novel environment, snails, which normally live in water, were placed on a flat dry surface to simulate the potentially threatening consequence of being in an arid environment. This stimulus initiated two distinct phases in snail behaviour: slow circular movements, followed by intense locomotion in a chosen direction. The first phase was prolonged when the test arena was symmetrically lit, compared with one with an apparent gradient of light. However, forced muscular locomotion for 2h prior to the test promoted the transition from random circular motions to a directional crawl, accompanied by an increase in crawling speed but with no effect on the choice of direction. Intense locomotion for 2 h also produced a strong excitatory effect on the activity of serotonergic neurons in L. stagnalis Our results suggest that the beneficial effects of physical exercise on cognitive performance in mammals might have deep roots in evolution, granting the opportunity to unravel the origins of such effects at the single-neuron and network levels.

Infection with schistosome parasites in snails leads to increased predation by prawns: implications for human schistosomiasis control

Schistosomiasis - a parasitic disease that affects over 200 million people across the globe - is primarily transmitted between human definitive hosts and snail intermediate hosts. To reduce schistosomiasis transmission, some have advocated disrupting the schistosome life cycle through biological control of snails, achieved by boosting the abundance of snails' natural predators. But little is known about the effect of parasitic infection on predator-prey interactions, especially in the case of schistosomiasis. Here, we present the results of laboratory experiments performed on Bulinus truncatus and Biomphalaria glabrata snails to investigate: (i) rates of predation on schistosome-infected versus uninfected snails by a sympatric native river prawn, Macrobrachium vollenhovenii, and (ii) differences in snail behavior (including movement, refuge-seeking and anti-predator behavior) between infected and uninfected snails. In predation trials, prawns showed a preference for consuming snails infected with schistosome larvae. In behavioral trials, infected snails moved less quickly and less often than uninfected snails, and were less likely to avoid predation by exiting the water or hiding under substrate. Although the mechanism by which the parasite alters snail behavior remains unknown, these results provide insight into the effects of parasitic infection on predator-prey dynamics and suggest that boosting natural rates of predation on snails may be a useful strategy for reducing transmission in schistosomiasis hotspots.

Schistosome parasite alters snail behaviour

![Figure][1] Schistosoma mansoni cercaria. Photo credit: Chelsea Wood, University of Michigan. For such a tiny worm, the schistosome parasite causes a great deal of suffering. Infecting more than 200 million people worldwide and causing liver damage, kidney failure, infertility and cancer

Menadione Sodium Bisulphite (MSB) enhances the resistance response of tomato, leading to repel mollusc pests.

Snails and slugs are terrestrial gastropods representing an important biotic stress that adversely affects crop yields. These pests are typically controlled with molluscicides, which produce pollution and toxicity and further induce the evolution of resistance mechanisms, making pest management even more challenging. In our work, we have assessed the efficacy of two different plant defence activators, menadione sodium bisulphite (MSB) and 1,2,3-benzothiadiazole-7-thiocarboxylic acid S-methyl ester (BTH), as inducers of resistance mechanisms of the model plant for defence, Solanum lycopersicum, against the generalist mollusc Theba grasseti (Helicidae). The study was designed to test the feeding behaviour and choice of snails, and also to analyse the expression profile of different genes specifically involved in defence against herbivores and wounds. Our data suggest that, through the downregulation of the terpene volatile genes and the production of proteinase inhibitors, treated MSB plants may be less apparent to herbivores that use herbivore-induced plant volatiles for host location. By contrast, BTH was not effective in the treatment of the pest, probably owing to an antagonistic effect derived from the induction of both salicylic-acid-dependent and jasmonic-acid-dependent pathways. This information is crucial to determine the genetic basis of the choice of terrestrial gastropod herbivores in tomato, providing valuable insight into how the plant defence activators could control herbivore pests in plants. Our work not only reports for the first time the interaction between tomato and a mollusc pest but also presents the action of two plant defence inductors that seems to produce opposed responses by inducing resistance mechanisms through different defence pathways.

Consumer patchiness explained by volatile infochemicals in a freshwater ecosystem

Many animal species show considerable spatial variation in abundance within their habitats. Since they live in patchy environments where food resources are often heterogeneously distributed, it would be adaptive for them to have efficient chemoreceptive mechanisms to locate food resources over distances. In the current study we investigated whether gastropod consumers perceive and pursue odorant signals in three choice experiments which were conducted under semi‐natural conditions. We tested the foraging behavior of freshwater snails to targets containing odorant stimuli and whether the recognition of food finding signals subsequently leads to the aggregation of grazers on the corresponding resource patch. We demonstrate that freshwater gastropods are able to recognize odor bouquets as foraging infochemicals and that grazing of conspecifics causes an aggregation of grazers under natural conditions. Further, they appear to be able to distinguish between high‐ and low‐quality food resources based on resource‐quality specific odor bouquets. Our results suggest that the perception of volatile cues is a process relevant on environmental scales and thus a possible mechanism to explain the frequently observed patchy distribution of grazers in ecosystems.

Characterizing the effects of temperature on behavioral periodicity in golden apple snails (Pomacea canaliculata)

The golden apple snail (Pomacea canaliculata), an invasive freshwater species in Asia, has become a serious agricultural pest. Water temperature is one of the most important environmental factors influencing the survival, growth rate, reproduction and behavior of freshwater snails. For this reason, the behavioral periodicity of golden apple snails was examined at different water temperatures (15°C, 20°C, 25°C, and 30°C). We classified the snails' behaviors into 12 pre-defined categories each minute for 2days at each temperature. Five dominant behavioral categories (clinging to the side of the aquarium [clinging], clinging with sprawling out its antennae [clinging-NM], crawling on the bottom of the aquarium, crawling on the side of the aquarium and feeding) were selected for further analyses. Spectral analysis and cross-spectral analysis were applied to determine the periodicity of these behaviors. Snails spent less time in moving during photophase than scotophase at all temperatures. Behavioral periodicity was much longer at lower temperatures, for both motion and motionless behaviors except clinging-NM. Detrended correspondence analysis based on periodogram values clearly characterized the differences in behavior at the various temperatures. Behavioral turnover, assessed by cross-spectral analysis, was faster at higher temperatures, and Markov chain analysis supported this result by finding a lower probability of maintaining the current behavior at higher temperatures.

Digenean larvae--the cause and beneficiaries of the changes in host snails' thermal behavior.

Parasite-induced changes in host’s thermal preferences not only can be interpreted as a physiological defense response of the host but also can represent a pathological manifestation of the parasite. Both may become established in host-parasite relationships if they are beneficial for at least one of the counterparts. This study investigates parasite-induced changes in the thermoregulatory behavior of first intermediate hosts of Digenea (i.e. Lymnaea stagnalis and Planorbarius corneus), infected with Notocotylidae or Echinostomatidae larvae. The investigated parasite species developed different transmission strategies outside the body of a snail, which may imply a different effect on the behavior of their hosts. Notocotylus attenuatus in L. stagnalis and Notocotylus ephemera in P. corneus produce symptoms of anapyrexia, prolonging the lifespan of their hosts. By contrast, Echinoparyphium aconiatum in L. stagnalis and Echinostoma spiniferum in P. corneus interfere with defensive thermoregulatory behavior of host snails, causing their accelerated death. The results of laboratory research indicate that thermal preferences of the snails infected with all investigated trematodes facilitate the transmission of the parasites in environment.

Modeling behavior control of golden apple snails at different temperatures

The golden apple snail (Pomacea canaliculata) is a detrimental invasive pest of rice in Asia. Temperature is a critical factor to determine their invasiveness including the behavior and distribution of snails. In this study, the behavioral responses of golden apple snails acclimated to different water temperatures (15°C, 20°C, 25°C, and 30°C) were examined based on Markov chain analysis, Shannon entropy, and Random forest modeling. Markov chains revealed that most snails maintained their previous behavior at low temperatures, while behavior transition tended to be higher at high temperature. Shannon entropy was also dependent on temperature (low at low temperature and high at high temperature), indicating that snails maintained their previous behavior for a long time at low temperature regardless having motion and motionless behavior, whereas they changed continuously their behavioral types at high temperature. The Random forest model showed that Shannon entropy at low temperature was influenced by crawling at the bottom or at side of the aquarium (motion behavior), while clinging to the side of the aquarium or clinging to the side of the aquarium with stretching out antennae were important behaviors determining Shannon entropy at high temperature. Our results showed that snails controlled their behavior to reduce their thermal stress and maintain a stable internal state in harsh environment. With this mechanism, they are able to overwinter in the open fields with low temperature in Korea, resulting in the increase of potential damage in agricultural ecosystems. Therefore, further study on the development of adequate management system is required to avoid their invasiveness to open water systems and ecological impacts. Finally, Shannon entropy, Markov chain, and Random forest model are useful computation methods to quantify the effects of temperature changes on the behavior of golden apple snails.

Behavior in invasive New Zealand mud snails (Potamopyrgus antipodarum) is related to source population

Behavior can be an important determinant of invasion success. In the New Zealand mud snail (Potamopyrgus antipodarum), behavior is influential in predator avoidance and probably plays a role in dispersal. The present study investigated differences in behavior among populations of different asexual clones of this species and compared introduced populations characterized by various levels of invasiveness and New Zealand native clonal populations with respect to rheotactic, geotactic, photokinetic, and dispersal behaviors. There was a significant difference in behavior among populations in all behaviors evaluated. A population of a widespread clone (US1) behaved most differently from the other populations exhibiting differences in all behaviors including a greater propensity to disperse. These results indicate that there is a population and possibly a genotypic effect on behaviors in this freshwater snail, and this variation may help to explain why some clones are more invasive than others.

Migratory behaviour of the mangrove gastropod Cerithidea decollata under unfamiliar conditions

The mangrove gastropod Cerithidea decollata feeds on the ground at low tide and climbs trunks 2–3h before the arrival of water, settling about 40cm above the level that the incoming tide will reach at High Water (between 0, at Neap Tide, and 80cm, at Spring Tide). Biological clocks can explain how snails can foresee the time of the incoming tide, but local environmental signals that are able to inform the snails how high the incoming tide will be are likely to exist. To identify the nature of these possible signals, snails were translocated to three sites within the Mida Creek (Kenya), 0.3–3km away from the site of snail collection. The study sites had a much wider tidal range than the original site (up to 160cm), were dominated by Rhizophora mucronata trees and uninhabited by C. decollata. If cueing signals were linked to the upper mangrove belt (site-specific signals), the Avicennia marina area, translocation should affect snail behaviour; conversely, we could conclude that information on the height of the incoming tide should be widely available within the whole creek (widespread signals), independently from cues linked to the home area and home site. Tests were performed by releasing the snails close to vertical plastic pipes (2m high) following a standardized procedure. Results revealed that snails, even in such unfamiliar surroundings, climbed higher and earlier on pipes where the tide level would be higher, thus allowing rejection of the hypothesis of site specific signals. Where the tide exceeded 80cm, however, snail effort was not sufficient to avoid submersion and snails had to climb higher. Hypotheses on widespread signals possibly involved in modulating the migratory behaviour of C. decollata are discussed.

Effects of predation and parasitism on climbing behavior of the marine snail, Cerithidea scalariformis

In mangrove marshes in Florida, the marine snail, Cerithidea scalariformis, exhibits a tidally-induced climbing behavior in which snails forage on the substrate during low tides, then climb aerial roots of mangrove trees on incoming and high tides. Under field and laboratory conditions, we tested the conventional explanation that snails vertically migrate to avoid predators, and because populations of C. scalariformis are parasitized by a guild of larval trematodes, we quantified the additive effects of parasitism on climbing behavior. We found that snail climbing distance was significantly and positively associated with water height, with snails migrating 2.7 times higher during high tide than low tide. Climbing distance depended on the species of trematode infection, and differences in migration distance between low and high tides were reduced for two of the four trematode species, suggesting that parasitism can affect climbing behavior. In field and laboratory experiments with tethered snails, individuals experienced significant levels of predation 0–8cm above the substrate surface, which declined substantially at heights above 16cm. A laboratory experiment showed that in the presence of blue crabs, Callinectes sapidus, unparasitized snails climbed 53% higher than parasitized snails, and 37% higher than they would without the presence of a predator. Surprisingly, infected snails climbed the same distance in the presence or absence of a blue crab, suggesting that parasitism may physiologically affect a snail's ability to respond to predators. Our data show that predation and parasitism are significant driving forces behind the climbing behavior of C. scalariformis whereby parasitic infection may affect their interactions with marsh predators. Reduced climbing distance may be an adaptive benefit for the parasite that keeps snails closer to the mud surface, providing favorable conditions for free-swimming cercariae to find a second intermediate host, since cercariae can only be transmitted to the next host when the snail host is inundated. Thus, the migratory behavior of C. scalariformis is a behavioral adaptation to avoid predation and that body snatchers, such as larval trematodes, can greatly modify this behavior to increase their own evolutionary fitness.

Association between shell morphology of micro-land snails (genusPlectostoma) and their predator’s predatory behaviour

Predator–prey interactions are among the main ecological interactions that shape the diversity of biological form. In many cases, the evolution of the mollusc shell form is presumably driven by predation. However, the adaptive significance of several uncommon, yet striking, shell traits of land snails are still poorly known. These include the distorted coiled “tuba” and the protruded radial ribs that can be found in micro-landsnails of the genus Plectostoma. Here, we experimentally tested whether these shell traits may act as defensive adaptations against predators. We characterised and quantified the possible anti-predation behaviour and shell traits of Plectostoma snails both in terms of their properties and efficiencies in defending against the Atopos slug predatory strategies, namely, shell-apertural entry and shell-drilling. The results showed that Atopos slugs would first attack the snail by shell-apertural entry, and, should this fail, shift to the energetically more costly shell-drilling strategy. We found that the shell tuba of Plectostoma snails is an effective defensive trait against shell-apertural entry attack. None of the snail traits, such as resting behaviour, shell thickness, shell tuba shape, shell rib density and intensity can fully protect the snail from the slug’s shell-drilling attack. However, these traits could increase the predation costs to the slug. Further analysis on the shell traits revealed that the lack of effectiveness in these anti-predation shell traits may be caused by a functional trade-off between shell traits under selection of two different predatory strategies.

Possibility of “Comet-Like” Transport of Acetylcholine Receptors in Command <i>Helix</i> Neurons in Cellular Analog of Habituation

The presence of "comet-like" radial transport of acetylcholine receptors by actin microfilaments without the participation of myosin motors in the depression of acetylcholine-induced inward chloric current (ACh-current) in command neurons of defensive behavior of the land snail, Helix lucorum, in a cellular analog of habituation was investigated. For that purpose the effects of CK548, CK-636 (inhibitors of actin-related protein complex Arp2/3, whose activation triggers rapid actin polymerization and the formation of the "comet-like" tail on the actinic filament) and wiskostatin (an N-WASP protein inhibitor, activating Arp2/3) on the depression of ACh-current were studied. The attenuation of ACh-current depression was observed upon the addition of CK548. At the same time, CK-636 and wiskostatin irreversibly strengthened the depression of this current and suppressed its spontaneous recovery. The results of CK-548 action and its mathematical modeling allow suggesting the presence of "comet-like" transport of acetylcholine receptors, initiated by Arp2/3 protein complex in receptor endo and exocytosis in command neurons of Helix lucorum in a cellular analog of habituation. Irreversible inhibition of vital metabolic processes of the neuron by wiskostatin and CK-636, which lead to the decrease in the level of ATP, could have caused irreversible effects of these blockers on current depression.

Survival and behavior of Chinese mystery snails (Bellamya chinensis) in response to simulated water body drawdowns and extended air exposure

Nonnative invasive mollusks degrade aquatic ecosystems and induce economic losses worldwide. Extended air exposure through water body drawdown is one management action used for control. In North America, the Chinese mystery snail (Bellamya chinensis) is an invasive aquatic snail with an expanding range, but eradication methods for this species are not well documented. We assessed the ability of B. chinensis to survive different durations of air exposure, and observed behavioral responses prior to, during, and following desiccation events. Individual B. chinensis specimens survived air exposure in a laboratory setting for > 9 weeks, and survivorship was greater among adults than juveniles. Several B. chinensis specimens responded to desiccation by sealing their opercula and/or burrowing in mud substrate. Our results indicate that drawdowns alone may not be an effective means of eliminating B. chinensis. This study lays the groundwork for future management research that may determine the effectiveness of drawdowns when combined with factors such as extreme temperatures, predation, or molluscicides.

The influence of TCS on the growth and behavior of the freshwater snail, Physa acuta

Triclosan (TCS) is among the top 10 most persistent contaminants found in U.S. rivers, streams, lakes, and aquifers. Although TCS has not been found to be hazardous to humans, it can be toxic to aquatic environments and animals. The effects of TCS on growth rates and the locomotive behavior of the freshwater snail, Physa acuta, were studied by exposing snails to a range of environmentally-relevant trace concentrations previously documented in freshwater ecosystems. Effects of TCS on snail growth were calculated using a non-linear regression model, and effects on behavior were determined using a two-way analysis of variance. Environmentally relevant concentrations of TCS (0.5 to 1.0 μg/L) enhanced Physa growth rates at low concentrations, but slowed growth rates at concentrations greater than 5 μg/L. Acute exposure did not affect immediate snail behavior; however, chronically exposed snails moved more slowly than naïve snails. These data indicate that concentrations of TCS currently found in freshwater ecosystems can potentially affect the growth and behavior of snails.

Interpopulation variation in predator avoidance behavior of a freshwater snail to the same predator

The New Zealand mud snail ( Potamopyrgus antipodarum (J.E. Grey, 1843)) responds to the presence of predatory fish by moving to a safer environment. These experiments attempted to determine if predator detection by the snail results in specific responses to light and (or) gravity by the snail and if snails respond more or less to fish from their native lake compared with fish from a foreign lake. Snails and fish (Gobiomorphus cotidianus McDowall, 1975) were collected from lakes Alexandrina and Peorua from the South Island of New Zealand. Snails were placed in behavioral chambers and tested for their responses to the direction of light, vertical orientation with respect to gravity, and rate of movement in light and dark conditions. Snails from each lake were exposed to one of three treatments: plain water, water from fish from Lake Alexandrina, and water from fish from Lake Peorua. Results showed no effect of direction of light on behavior. Snails from Lake Alexandrina were not found to alter their up or down movements in response to the detection of fish. However, snails from Lake Peorua moved down more in response to fish from their own lake than fish from Lake Alexandrina or no fish. Both snail populations increase their speed in the light more when detecting Alexandrina fish compared with Peorua fish and no fish. Both snail populations show some evidence of enhanced response to local predator populations. Interestingly, different behavioral mechanisms appear to be responsible for the avoidance behaviors in each population.