Snail Locomotion Research Articles

The Effects of Repeated Administration of the Micellar Complex of Methylprednisolone on the Locomotor Activity of a Terrestrial Snails.

We studied the effects of repeated injections of methylprednisolone and its micellar complex with block-copolymer on locomotor activity of a terrestrial snail. It was shown that methylprednisolone solution injected into the hemolymph of the animal produced a direct effect on the muscle system of the animal as soon as 1 h after administration: it slowed down snail locomotion and reduced contractile activity of the foot muscles. The micellar complex of methylprednisolone with block-copolymer prevented this effect during the first 2 days of injection and negatively affected locomotion only in 2 days after injection, the decrease in locomotion in this case was not accompanied by a decrease in contractile activity of the foot muscle.

The frictional and adhesive properties of the shells of terrestrial hairy snails

AbstractHair‐like structures of the shell in some terrestrial snails have been suggested to represent an adaptive advantage. One of the recently proposed explanations was the hypothesis that the possession of hairs facilitates the snails' adherence to the leaves of the plants during foraging, when humidity levels are high. In order to obtain some reliable data to test this contact mechanics hypothesis, the present paper deals with the frictional and adhesive properties of the smooth and hairy shells of two species of terrestrial mollusks, Trochulus hispidus and T. villosulus. Additionally, actively generated traction force of the snails was measured on different substrates. The conducted experiments revealed that in wet conditions the hairiness indeed increases friction and that adhesion through the water film is high enough to retain the weight of the snail. However, possession of long hairs decreases the adhesion, in comparison with the animals with short hairs. Our data suggest that hair‐like structures require more energy expenditure during locomotion and only provide the advantage of higher adhesion on wet substrates. Obtained maximal traction forces were about 30 times higher than friction forces of the shell surface dragged over the substrate. Neither wetting condition of the substrate nor surface roughness had considerable effect on the traction forces of snails. Therefore, the function of the hair‐like structures seems not to be related with snail locomotion and adhesion.

Suitable configurations for pneumatic soft sheet actuator to generate traveling waves

This paper presents suitable configurations for a pneumatic soft sheet actuator capable of moving by traveling waves. Inspired by the locomotion of snails and slugs using pedal foot generating traveling waves, we challenge to develop a pneumatic sheet type actuator named Wavy-sheet, aiming to make it move even on a fragile environment which the wheel-type robots are hard to cross over. To design the suitable configuration to fulfill the above purpose, first, we derive combinations of realizable waveform patterns from a mathematical point of view and examine the characteristics of the waves. Next, after a couple of desired configurations are selected from the aspects of velocity and payload, their prototypes are fabricated. Finally, to verify the validity of our consideration, the experiments are conducted, and the most suitable configuration for the proposed actuator is determined.

The antidepressants venlafaxine (“Effexor”) and fluoxetine (“Prozac”) produce different effects on locomotion in two species of marine snail, the oyster drill (Urosalpinx cinerea) and the starsnail (Lithopoma americanum)

Human antidepressants have been previously shown to induce foot detachment from the substrate in aquatic snails. Prior to foot detachment, antidepressants also affect snail crawling speed. We tested two commonly prescribed antidepressants, venlafaxine (“Effexor”) and fluoxetine (“Prozac”) on crawling speed and time to reach the air–water interface in two species of marine snail, the oyster drill Urosalpinx cinerea and the American starsnail Lithopoma americanum. Exposure to venlafaxine increased crawling speed in both species, while fluoxetine slowed them down. Our lowest LOEC (lowest observed effect concentration) was 31.3 μg/L venlafaxine in Urosalpinx. Similarly, snails (L. americanum) exposed to venlafaxine tended to move faster and more often to the air–water interface, but exposure to fluoxetine slowed them down. Our lowest LOEC was 345 μg/L fluoxetine in Lithopoma. These results indicate that venlafaxine boosts locomotion, while fluoxetine reduces it, and both behaviors are preludes to foot detachment. The different effects of these two antidepressants on snail locomotion suggest differing physiological mechanisms of action in marine snails as well as possible ecological consequences.

Snails and their trails: the multiple functions of trail‐following in gastropods

Snails are highly unusual among multicellular animals in that they move on a layer of costly mucus, leaving behind a trail that can be followed and utilized for various purposes by themselves or by other animals. Here we review more than 40 years of experimental and theoretical research to try to understand the ecological and evolutionary rationales for trail-following in gastropods. Data from over 30 genera are currently available, representing a broad taxonomic range living in both aquatic and terrestrial environments. The emerging picture is that the production of mucus trails, which initially was an adaptation to facilitate locomotion and/or habitat extension, has evolved to facilitate a multitude of additional functions. Trail-following supports homing behaviours, and provides simple mechanisms for self-organisation in groups of snails, promoting aggregation and thus relieving desiccation and predation pressures. In gastropods that copulate, trail-following is an important component in mate-searching, either as an alternative, or in addition to the release of water- or air-borne pheromones. In some species, this includes a capacity of males not only to identify trails of conspecifics but also to discriminate between trails laid by females and males. Notably, trail discrimination seems important as a pre-zygotic barrier to mating in some snail species. As production of a mucus trail is the most costly component of snail locomotion, it is also tempting to speculate that evolution has given rise to various ways to compensate for energy losses. Some snails, for example, increase energy intake by eating particles attached to the mucus of trails that they follow, whereas others save energy through reducing the production of their own mucus by moving over previously laid mucus trails. Trail-following to locate a prey item or a mate is also a way to save energy. While the rationale for trail-following in many cases appears clear, the basic mechanisms of trail discrimination, including the mechanisms by which many snails determine the polarity of the trail, are yet to be experimentally determined. Given the multiple functions of trail-following we propose that future studies should adopt an integrated approach, taking into account the possibility of the simultaneous occurrence of many selectively advantageous roles of trail-following behaviour in gastropods. We also believe that future opportunities to link phenotypic and genotypic traits will make possible a new generation of research projects in which gastropod trail-following, its multitude of functions and evolutionary trade-offs can be further elucidated.

711 陸生軟体腹足動物(カタツムリ)の生体トライボロジー応用研究 : カタツムリの移動機構を応用した柔らかいアクチュエータの開発[続](OS8-3 表面の機能化と薄膜・トライポロジー(3),OS8 表面の機能化と薄膜・トライポロジー)

711 陸生軟体腹足動物(カタツムリ)の生体トライボロジー応用研究 : カタツムリの移動機構を応用した柔らかいアクチュエータの開発[続](OS8-3 表面の機能化と薄膜・トライポロジー(3),OS8 表面の機能化と薄膜・トライポロジー)

Crawling motility through the analysis of model locomotors: Two case studies

We study model locomotors on a substrate, which derive their propulsive capabilities from the tangential (viscous or frictional) resistance offered by the substrate. Our aim is to develop new tools and insight for future studies of cellular motility by crawling and of collective bacterial motion. The purely viscous case (worm) is relevant for cellular motility by crawling of individual cells. We re-examine some recent results on snail locomotion in order to assess the role of finely regulated adhesion mechanisms in crawling motility. Our main conclusion is that such regulation, although well documented in several biological systems, is not indispensable to accomplish locomotion driven by internal deformations, provided that the crawler may execute sufficiently large body deformations. Thus, there is no snail theorem. Namely, the crawling analog of the scallop theorem of low Reynolds number hydrodynamics does not hold for snail-like crawlers. The frictional case is obtained by assuming that the viscous coefficient governing tangential resistance forces, which act parallel and in the direction opposite to the velocity of the point to which they are applied, depends on the normal force acting at that point. We combine these surface interactions with inertial effects in order to investigate the mechanisms governing the motility of a bristle-robot. This model locomotor is easily manufactured and has been proposed as an effective tool to replicate and study collective bacterial motility.

Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.

Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

Discrete Movements of Foot Epithelium during Adhesive Locomotion of a Land Snail

During the adhesive locomotion of land snails a series of short dark transverse bands, called pedal or foot waves, is visible ifa moving snail's ventral surface is observed through a sheet of glass. Moreover, the mucus secreted from the pedal glands and some pedal epithelial cells forms a thin layer which acts as a glue augmenting adherence, while also acting as a lubricant under the moving parts of the snail's foot. The relationships between velocity and the frequency of pedal waves as well as changes in the volume of small air bubbles under foot waves were analyzed by means of digital recordings made through a glass sheet on which the snails were moving. On the ventral surface of a moving snail foot, the adhering parts of the foot constituted about 80% of the total area, while several moving parts only about 20%. The single moving region of the foot (the pedal wave) amounted to about 3% of snail length. The epithelium in the region of the pedal wave was arched above the substrate and was also more wrinkled than the stationary epithelium, which enabled the forward motion of each specific point of epithelium during the passage of a pedal wave above it. The actual area of epithelium engaged by a pedal wave was at least 30% greater than the area of the epithelium as recorded through a glass sheet. In the region of the pedal wave, the tiny subepithelial muscles acting on the epithelium move it up in the front part of the wave, and then down at the end of the wave, operating vertically in relation to the substrate. In the middle part of the wave, the epithelium only moves forward. In summary, during the adhesive locomotion of snails, the horizontal movement of the ventral surface epithelium proceeds as temporally separate phases of upward, forward and downward movement.

2A1-O02 螺旋型波動伝播式移動機構を用いた壁面登攀ロボットの開発(特殊移動ロボット(1))

In recent years, robots that can substitute for humans in dangerous activities, contributing to safety, cost reduction and efficiency have been developed. For example, a wall-climbing robot can clean and inspect high places, and approach disaster sites where a person cannot reach. In this study, the locomotion of snails is used as an effective wall-climbing mechanism. A snail moves by generating travelling waves with its muscle elasticity and propagating the wave in the direction of movement. Since this locomotion mechanism is in contact with a large area of ground, it is extremely stable. This is advantageous in climbing unstable walls. The proposed robot uses several Spiral style Wave transmission system for locomotion and a fan to adhere to the wall by suction. We confirmed that this robot successfully climbs wall.

727 陸生軟体腹足動物(カタツムリ)の生体トライボロジー応用研究カタツムリの移動機構を応用した柔らかいアクチュエータの開発(GS 機素・潤滑・設計)

727 陸生軟体腹足動物(カタツムリ)の生体トライボロジー応用研究カタツムリの移動機構を応用した柔らかいアクチュエータの開発(GS 機素・潤滑・設計)

2A2-L15 ファン・デュアルホーキンスリンクを用いた壁面登攀ロボットの開発(特殊移動ロボット)

In recent years, robots that can substitute for humans in dangerous activities, contributing to safety, cost reduction and efficiency have been developed. For example, a wall-climbing robot can clean and inspect high places, and approach disaster sites where a person cannot reach. In this study, the locomotion of snails is used as an effective wall-climbing mechanism. A snail moves by generating travelling waves with its muscle elasticity and propagating the wave in the direction of movement. Since this locomotion mechanism is in contact with a large area of ground, it is extremely stable. This is advantageous in climbing unstable walls. The proposed robot uses several Dual Hoekens linkages for locomotion and a fan to adhere to the wall by suction. We confirmed that this robot successfully climbs wall.

1P1-O16 ポテンシャル法を用いた進行波形全方向移動ロボット(TORoIII)の経路追従制御(バイオロボティクス)

The traveling wave type omni-directional mobile robot (TORoIII) imitates the snail locomotion mechanism. An advantage of this movement mechanism is to be able to do a stable run because the landing area is large. The other omni-directional movement mechanism has the fault that is eacy to slip, but This robot can do the stable run by imitating locomotion mechanism of a snail. In this paper, we proposes the method of omni-directional locomotion for TORoIII and the method of path tracking based on potential method. In addition, we conducted the running experiment using these method. As a result, the running of TORoIII could be controlled.

2P1-D29 ファン-スライダ・クランク機構を用いた壁面登攀ロボットの開発

In recent years, robots that can substitute for humans in dangerous activities, contributing to safety, cost reduction and efficiency have been developed. For example, a wall-climbing robot can clean and inspect high places, and approach disaster sites where a person cannot reach. In this study, the locomotion of snails is used as an effective wall-climbing mechanism. A snail moves by generating travelling waves with its muscle elasticity and propagating the wave in the direction of movement. Since this locomotion mechanism is in contact with a large area of ground, it is extremely stable. This is advantageous in climbing unstable walls. The proposed robot uses several slider cranks for locomotion and a fan to adhere to the wall by suction. We confirmed that this robot successfully climbs various walls.

1A1-K12 ファン-スライダクランク機構を用いた波動伝播式壁面登攀ロボットの開発

In recent years, robots that can substitute for humans in dangerous activities, contributing to safety, cost reduction and efficiency have been developed. For example, a wall-climbing robot can clean and inspect high places, and approach disaster sites where a person cannot reach. In this study, the locomotion of snails is used as an effective wall-climbing mechanism. A snail moves by generating travelling waves with its muscle elasticity and propagating the wave in the direction of movement. Since this locomotion mechanism is in contact with a large area of ground, it is extremely stable. This is advantageous in climbing unstable walls. The proposed robot uses several slider cranks for locomotion and a fan to adhere to the wall by suction. We confirmed that this robot successfully climbs various walls.

1A1-K13 進行波を用いた全方向移動ロボットの移動方法

Presently, the wheel mechanism is mainly used as a mechanism which moves in the ground. However, the wheel mechanism is difficult to run at the narrow and complicated pass which exists in a hospital and a factory. Therefore, an omni-directional mobile mechanism which can move freely at such a place is required. The omni wheel is mostly used at this mechanism. However, the omni wheel has the fault that a steady run is difficult because it is slippery. On the other hand, the snail has the locomotion mechanism using the traveling wave. This locomotion mechanism is not easy to slip. In addition, this locomotion mechanism can move omnidirectionaly by changing the propagative direction of the traveling wave. Therefore, we developed the omni-directional mobile robot using the snail locomotion mechanism. And, we studied the locomotion strategies of the robot.

Crawling beneath the free surface: Water snail locomotion

Land snails move via adhesive locomotion. Through muscular contraction and expansion of their foot, they transmit waves of shear stress through a thin layer of mucus onto a solid substrate. Since a free surface cannot support shear stress, adhesive locomotion is not a viable propulsion mechanism for water snails that travel inverted beneath the free surface. Nevertheless, the motion of the freshwater snail, Sorbeoconcha physidae, is reminiscent of that of its terrestrial counterparts, being generated by the undulation of the snail foot that is separated from the free surface by a thin layer of mucus. Here, a lubrication model is used to describe the mucus flow in the limit of small-amplitude interfacial deformations. By assuming the shape of the snail foot to be a traveling sine wave and the mucus to be Newtonian, an evolution equation for the interface shape is obtained and the resulting propulsive force on the snail is calculated. This propulsive force is found to be nonzero for moderate values of the capillary number but vanishes in the limits of high and low capillary number. Physically, this force arises because the snail’s foot deforms the free surface, thereby generating curvature pressures and lubrication flows inside the mucus layer that couple to the topography of the foot.

Development of an omni‐directional mobile robot using traveling waves based on snail locomotion

PurposeThe snail moves by propagating traveling waves from tail to head. If it is possible to propagate a traveling wave in many directions, an omni‐directional mobile robot could be realized. The purpose of this paper is to develop an omni‐directional mobile robot using the locomotion mechanism of the snail and to study the basic properties of the robot.Design/methodology/approachA unit for mobile robot was developed to generate the traveling wave based on the snail. The omni‐directional mobile robot is composed of eight units arranged in a circular shape and each abutting unit is connected by a spring. The robot generates a traveling wave by elongation and contraction of the units and realizes an omni‐directional locomotion.FindingsIt was confirmed that the robot moves using the traveling wave locomotion. Furthermore, the locomotion experiment confirmed that the robot moved in the expected direction with reasonable accuracy.Originality/valueThis paper proposes a new omni‐directional mobile mechanism using traveling wave based on a snail locomotion. Since the locomotion mechanism of the snail involves moving a larger area than is the case with other creatures, it is able to move not only on irregular ground such as swamps, but also on walls and ceilings. Hence, it is thought that this robot could be applied to the inspection of walls.

1P1-C06 カタツムリの移動様式を用いた進行波型全方向移動ロボットの開発(バイオミメティクス・ロボティクス)

1P1-C06 カタツムリの移動様式を用いた進行波型全方向移動ロボットの開発(バイオミメティクス・ロボティクス)

Octopamine boosts snail locomotion: behavioural and cellular analysis

We measured the reduction in locomotion of unrestrained pond snails, Lymnaea stagnalis, subsequent to transdermal application of two selective octopamine antagonists, epinastine and phentolamine. After 3 h in fresh standard snail water following treatment with 4 mM epinastine or 3.5 mM phentolamine, the snails' speed was reduced to 25 and 56% of the controls (P < 0.001 and P = 0.02, respectively). The snails' speed decreased as the drug concentration increased. In the isolated CNS, 0.5 mM octopamine increased the firing rate of the pedal A cluster motoneurons, which innervate the cilia of the foot. In normal saline the increase was 26% and in a high magnesium/low calcium saline 22% (P < 0.05 and 0.01, respectively). We conclude that octopamine is likely to modulate snail locomotion, partially through effects on pedal motoneurons.