Soft actuators are inherently flexible and compliant,traits that enhance their adaptability to diverse environments and tasks.However,their low structural stiffness can lead to unpredictable and uncontrollable complex...Soft actuators are inherently flexible and compliant,traits that enhance their adaptability to diverse environments and tasks.However,their low structural stiffness can lead to unpredictable and uncontrollable complex deformations when substantial force is required,compromising their load-bearing capacity.This work proposes a novel method that uses gecko setae-inspired adhesives as interlayer films to construct a layer jamming structure to adjust the stiffness of soft actuators.The mechanical behavior of a single tilted microcylinder was analyzed using the energy method to determine the adhesion force of the adhesives.The gecko-inspired adhesive was designed under the guidance of the adhesion force model.Testing under various loads and directions revealed that the tilted characteristic of microcylinders can enhance the adhesion force in its grasping direction.The adhesive demonstrated excellent adhesion performance compared to other typical adhesives.A tunable stiffness actuator using gecko setae-inspired adhesives(TSAGA),was developed with these adhesives serving as interlayer films.The stiffness model of TSAGA was derived by analyzing its axial compression force.The results of stiffness test indicate that the adhesives serve as interlayer films can adjust the stiffness in response to applied load.TSAGA was compared with other typical soft actuators in order to evaluate the stiffness performance,and the results indicate that TSAGA exhibits the highest stiffness and the widest tunable stiffness range.This demonstrates the superior performance of the setae-inspired adhesives as interlayer films in terms of stiffness adjustment.展开更多
In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of ti...In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this paper.The bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the surfaces.The special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography technology.These two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different surfaces.This foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.展开更多
Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierar...Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierarchical structure of the legs,which are covered with a large number of inclined setae with fine nanogrooves inducing water resistance.This inspires us to fabricate special water-repellent structure on functional surfaces through the cooperation between the surface treatment and the surface micro-and nanostructures,which may bring great advantages in a wide variety of applications.In this paper we present a procedure for fabricating biomimetic water strider legs covered with setae using Polycarbonate Track-Etched(PCTE)membranes as templates.By choosing appropriate membrane lengths,diameters,pitches and densities of the setae,the biomimetic legs can be fabricated conveniently and at a low cost.Furthermore we investigated the relationship between stiffness of the molding materials,high aspect ratio and density,which affect the fidelity of fabrication and self adhesion,to optimize the stability of setae.The knowledge we gained from this study will offer important insights into the biomimetic design and fabrication of water strider setae.展开更多
Shrimps of the genus Synalpheus(Caridea)are commonly found in subtropical and tropical marine habitats around the world.The present work aims to provide the first description of the reproductive system of this genus u...Shrimps of the genus Synalpheus(Caridea)are commonly found in subtropical and tropical marine habitats around the world.The present work aims to provide the first description of the reproductive system of this genus using histological,histochemical,and morphological perspectives to elucidate the gonochoric or hermaphrodite sexual system in this genus.Males have a slender and very translucent reproductive system that is challenging to observe.The entire cephalothorax was histologically sectioned to ensure that all regions of the reproductive system could be identified.This non-gambarelloides group shows a gonochoric condition.The caridean pattern of the reproductive system was observed where the male has a pair of testes and a pair of very thin vasa deferentia,ending at the opening of the gonopore.Spermatophore structure is absent,without any layers surrounding the spermatozoa that are aggregated in a sperm mass.In females,the reproductive system consists of a pair of ovaries that extend to the end of the pleon.The extension of the ovary has a particular pattern compared to other caridean shrimps.Here,we hypothesize that males invest energy on somatic morphological structures to protect the host and female,using the larger pistol-like cheliped,while females invest energy in reproduction since all the members of this group are typical"pair-bond"examples.The observed pattern of the reproductive male morphology could also be evidence of a possible synapomorphy for this genus within theinfraorder.展开更多
Scanning electron microscopy (SEM) and histological techniques were used to observe and study the setae structures of two gecko species (G. gecko and G. swinhonis) and the relationships between these structures and th...Scanning electron microscopy (SEM) and histological techniques were used to observe and study the setae structures of two gecko species (G. gecko and G. swinhonis) and the relationships between these structures and the adhesive forces. The SEM results showed that the setae of these two species were densely distributed in an orderly fashion, and branched with curved tips. The setae of G. gecko had cluster structures, each cluster containing 4-6 setae whose terminal branches curved towards the center of the toes at ~ 10o, the tips of the branches like spatulae and densely arrayed at an interval of less than 0.2―0.3 μm. On the contrary, the branch tips in the setae of G. swinhonis were curled, and the terminal parts of setae curved towards the center of the toes at various angles. Usually the setae of these gecko species branch twice at the top at intervals greater than that of G. gecko. The histological observation found that inside the setae of these two species there were plenty of unevenly distributed contents, such as epithelia, fat cells, pigmental cells and muscle tissue, but no gland cells existed. The results of functional experiments suggested that modifying the structure of gecko’s setae could reduce its adhesive ability dramatically, demonstrating the positive correlation between the structure of the gecko’s setae and its adhesive ability. The above results provide important information in designing bio-mimic setae and bio-gecko robots.展开更多
The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der W...The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.展开更多
Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees a...Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees and,consequently,may threaten human and animal health during outbreaks,causing dermatitis,conjunctivitis and respiratory distress.Although some studies provide detailed information about the setae,particularly those of the pine processionary moth Thaumetopoea pityocampa,there is little knowledge on the morphological traits of the setae and their release by the larvae.In the present study we identify major traits of the setae of 3 species of processionary moth,T.pityocampa,T.pinivora and T.processionea,which are potentially helpful in the understanding of setae dynamics in the environment:(i)diameter and length of setae and(ii)analysis of dynamical properties of the setae in the airborne state.Setae are highly variable in size,with bimodal distribution in T.pityocampa and T.pinivora;in these 2 species,short and long setae are interspersed within the integument fields where they occur.The difference in the seta size has important consequences in dispersion,as smaller setae can spread 5 times further than their bigger counterparts.This information is relevant for a full understanding of the defensive importance of larval setae against natural enemies of the processionary moths,as well for elucidating the importance of the processionary setae as air pollutants,both close to the infested trees and at longer distances.展开更多
Water striders are insects living on the water surface, over which they can move very quickly and rarely get wetted. We measured the force of free walking in water striders, using a hair attached to their backs and a ...Water striders are insects living on the water surface, over which they can move very quickly and rarely get wetted. We measured the force of free walking in water striders, using a hair attached to their backs and a 3D strain gauge. The error was calculated by comparing force and data derived from geometry and was estimated as 13%. Females on average were stronger （1.32 mN） than males （0.87 mN）, however, the ratio of force to weight was not significantly different. Compared with other lighter species, Aquarius paludum seems stronger, but the ratio of force to weight is actually lower. A. paludum applies about 0.3 mN.cm^-1 to 0.4 mN.cm 1 with its mid-legs, thus avoiding penetrating the surface tension layer while propelling itself rapidly over the water surface. We also investigated the external morphology with SEM. The body is covered by effectively two layers of macro-and micro-hairs, which renders them hydrophobic. The setae are long （40 μm-60μm） and stiff, being responsible for waterproofing, and the microtrichia are much smaller （〈10μm）, slender, and flexible, holding a bubble over the body when submerged.展开更多
Egg incubation on the female abdomen is the parental care behavior observed in aeglids,in which eggs are kept adhered to maternal pleopods and maintained,cleaned and aerated.In A.platensis,egg attachment occurs with t...Egg incubation on the female abdomen is the parental care behavior observed in aeglids,in which eggs are kept adhered to maternal pleopods and maintained,cleaned and aerated.In A.platensis,egg attachment occurs with the aid of pleopodal setae,which are twisted around their axis in the distal region,forming the funiculus,and pleopodal glands,which are responsible for the production of the adhesive substance that seems to be involved in egg fixation to pleopodal setae.Those glands are acini formed by secretory cells arranged concentrically around a central duct,giving them a rosette appearance.Two types of secretory cells were observed,those that produce electron-lucid vesicles and those having electron-dense ones.Both kinds of vesicles are released in a duct whose opening pore is located on the pleopodal surface and constitute the adhesive substance that coats eggs and pleopodal setae,ensuring egg fixation to the female body and maternal care maintenance.This study investigates the internal and external morphology of Aegla platensis pleopods,to understand the egg attachment process and identify the structures involved in this phenomenon.Three microscopy techniques are used:scanning electron microscopy(SEM),transmission electron microscopy(TEM),and optical microscopy(OM).展开更多
A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part sur...A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part surface and lateral to the legs which are different in size, arrangement and shape. These setae have different lengths and many thorns on the whole seta. The top ends of these setae stand up without furcations which direct uprightly towards the surface of the touched soil. By the method of removing these setae, getting the insect weight before and after digging into the dung we affirm farther that the setae on the beetle body surface form the anti-stick and non-adherent gentle interface. The soil machines and components made by imitating the gentle body surface of beetles have favorable non-adherent results.展开更多
It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively ...It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.展开更多
The anisotropic setae structures of geckos demonstrate a natural anisotropic response to external forces,thereby enabling rapid and repeated attachment and detachment.Considering this biological mechanism,this study p...The anisotropic setae structures of geckos demonstrate a natural anisotropic response to external forces,thereby enabling rapid and repeated attachment and detachment.Considering this biological mechanism,this study proposes an innovative process that harnesses the overcuring of resins in digital light processing(DLP)3D printing to emulate setae structures.The proposed method facilitates the spontaneous fabrication of anisotropic shapes from isotropically modeled geometries.Furthermore,it reduces the number of hierarchical structures typically produced in conventional 3D printing and creates smooth surfaces,thereby enhancing the structural stability for directional adhesion and detachment.The anisotropic structures were processed into functional surfaces through a double-casting method,exhibiting an adhesive strength akin to that of gecko-setae structures while maintaining easy detachment capabilities.Finally,a simple mechanical module was fabricated to directly demonstrate the detachment effect.This study introduces a novel approach to DLP printing for fabricating enhanced anisotropic structures that can be seamlessly integrated with existing 3D printing techniques.By strategically utilizing overcuring,a phenomenon often perceived as a limitation,this study demonstrated its potential to expand the boundaries of next-generation 3D printing technologies.展开更多
Summary What is already known about this topic?Redoa leucoscela(R.leucoscela)Collenette(Lepidoptera:Erebidae),releases urticating setae during larval molting.These setae disperse through aquatic and aerial pathways an...Summary What is already known about this topic?Redoa leucoscela(R.leucoscela)Collenette(Lepidoptera:Erebidae),releases urticating setae during larval molting.These setae disperse through aquatic and aerial pathways and can trigger allergic reactions upon dermal contact.Clinical manifestations include pruritic dermatitis with stinging sensations and papular lesions;untreated cases may progress to systemic reactions or secondary infections.展开更多
The remarkable ability of geckos to climb and run rapidly on walls and ceilings has recently received considerable interest from many researchers.Significant progress has been made in understanding the attachment and ...The remarkable ability of geckos to climb and run rapidly on walls and ceilings has recently received considerable interest from many researchers.Significant progress has been made in understanding the attachment and detachment mechanisms and the fabrication of articulated gecko-inspired adhesives and structured surfaces.This article reviews the direct experiments that have investigated the properties of gecko hierarchical structures,i.e.,the feet,toes,setae,and spatulae,and the corresponding models to ascertain the mechanical principles involved.Included in this review are reports on gecko-inspired surfaces and structures with strong adhesion forces,high ratios of adhesion and friction forces,anisotropic hierarchical structures that give rise to directional adhesion and friction,and“intelligent”attachment and detachment motions.展开更多
基金supported by Jiangsu Special Project for Frontier Leading Base Technology(Grant Nos.BK20192004)Fundamental Research Funds for Central Universities(Grant Nos.B240201190)+3 种基金Changzhou Social Development Science and Technology Support Project(Grant Nos.CE20225037)Changzhou Science and Technology Project(Grant Nos.CM20223014)Suzhou Key Industrial Technology Innovation Forward-Looking Application Research Project(Grant Nos.SYG202143)Changzhou Science and Technology Project(Grant Nos.CJ20241061).
文摘Soft actuators are inherently flexible and compliant,traits that enhance their adaptability to diverse environments and tasks.However,their low structural stiffness can lead to unpredictable and uncontrollable complex deformations when substantial force is required,compromising their load-bearing capacity.This work proposes a novel method that uses gecko setae-inspired adhesives as interlayer films to construct a layer jamming structure to adjust the stiffness of soft actuators.The mechanical behavior of a single tilted microcylinder was analyzed using the energy method to determine the adhesion force of the adhesives.The gecko-inspired adhesive was designed under the guidance of the adhesion force model.Testing under various loads and directions revealed that the tilted characteristic of microcylinders can enhance the adhesion force in its grasping direction.The adhesive demonstrated excellent adhesion performance compared to other typical adhesives.A tunable stiffness actuator using gecko setae-inspired adhesives(TSAGA),was developed with these adhesives serving as interlayer films.The stiffness model of TSAGA was derived by analyzing its axial compression force.The results of stiffness test indicate that the adhesives serve as interlayer films can adjust the stiffness in response to applied load.TSAGA was compared with other typical soft actuators in order to evaluate the stiffness performance,and the results indicate that TSAGA exhibits the highest stiffness and the widest tunable stiffness range.This demonstrates the superior performance of the setae-inspired adhesives as interlayer films in terms of stiffness adjustment.
基金This research was supported by the National Natural Science Foundation of China(No.11774355).
文摘In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this paper.The bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the surfaces.The special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography technology.These two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different surfaces.This foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.
文摘Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierarchical structure of the legs,which are covered with a large number of inclined setae with fine nanogrooves inducing water resistance.This inspires us to fabricate special water-repellent structure on functional surfaces through the cooperation between the surface treatment and the surface micro-and nanostructures,which may bring great advantages in a wide variety of applications.In this paper we present a procedure for fabricating biomimetic water strider legs covered with setae using Polycarbonate Track-Etched(PCTE)membranes as templates.By choosing appropriate membrane lengths,diameters,pitches and densities of the setae,the biomimetic legs can be fabricated conveniently and at a low cost.Furthermore we investigated the relationship between stiffness of the molding materials,high aspect ratio and density,which affect the fidelity of fabrication and self adhesion,to optimize the stability of setae.The knowledge we gained from this study will offer important insights into the biomimetic design and fabrication of water strider setae.
基金I.R.R.M.andA.L.C.were fundedby"Conselho Nacional de Desenvolvimento Cientifico e Tecnologico"(CNPQ grantPQ311034/2018-7)"Coordenacaode Aperfeicoamento deNivelSuperior-CAPES,Brazil(CAPES PRINT 88881.310767/2018-01,CAPES PROEX 23038.000802/2018-25)+2 种基金FJ.Z.would like to thank the laboratory support provided by the_Sao Paulo Research Foundation-FAPESP(JP#2005/04707-5 and Biota Intercrusta#2018/13685-5)CAPES-Ciencias do Mar II program(grant#1989/2014,23038.004309/2014-51)CNPq Research Scholarship(PQ2#309298-2020-2,PQ1D#308324/2023-4),and CNPq PPBio 2023/0723.
文摘Shrimps of the genus Synalpheus(Caridea)are commonly found in subtropical and tropical marine habitats around the world.The present work aims to provide the first description of the reproductive system of this genus using histological,histochemical,and morphological perspectives to elucidate the gonochoric or hermaphrodite sexual system in this genus.Males have a slender and very translucent reproductive system that is challenging to observe.The entire cephalothorax was histologically sectioned to ensure that all regions of the reproductive system could be identified.This non-gambarelloides group shows a gonochoric condition.The caridean pattern of the reproductive system was observed where the male has a pair of testes and a pair of very thin vasa deferentia,ending at the opening of the gonopore.Spermatophore structure is absent,without any layers surrounding the spermatozoa that are aggregated in a sperm mass.In females,the reproductive system consists of a pair of ovaries that extend to the end of the pleon.The extension of the ovary has a particular pattern compared to other caridean shrimps.Here,we hypothesize that males invest energy on somatic morphological structures to protect the host and female,using the larger pistol-like cheliped,while females invest energy in reproduction since all the members of this group are typical"pair-bond"examples.The observed pattern of the reproductive male morphology could also be evidence of a possible synapomorphy for this genus within theinfraorder.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 30400086, 30470230, 30770285 and 60535020)
文摘Scanning electron microscopy (SEM) and histological techniques were used to observe and study the setae structures of two gecko species (G. gecko and G. swinhonis) and the relationships between these structures and the adhesive forces. The SEM results showed that the setae of these two species were densely distributed in an orderly fashion, and branched with curved tips. The setae of G. gecko had cluster structures, each cluster containing 4-6 setae whose terminal branches curved towards the center of the toes at ~ 10o, the tips of the branches like spatulae and densely arrayed at an interval of less than 0.2―0.3 μm. On the contrary, the branch tips in the setae of G. swinhonis were curled, and the terminal parts of setae curved towards the center of the toes at various angles. Usually the setae of these gecko species branch twice at the top at intervals greater than that of G. gecko. The histological observation found that inside the setae of these two species there were plenty of unevenly distributed contents, such as epithelia, fat cells, pigmental cells and muscle tissue, but no gland cells existed. The results of functional experiments suggested that modifying the structure of gecko’s setae could reduce its adhesive ability dramatically, demonstrating the positive correlation between the structure of the gecko’s setae and its adhesive ability. The above results provide important information in designing bio-mimic setae and bio-gecko robots.
基金supported by the National Basic Research Program of China (Grant No. 2011CB302106)the National Natural Science Foundation of China (Grant Nos. 30770285, 51175249, 61175105 and 51105201)the Jiangsu Natural Science Foundation (Grant No. BK2009376)
文摘The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.
基金This work was funded by the French National Research Agency in the framework of project ANR No.07BDIV 013‘URTICLIM’by the University of Padova grant 2010-C91J10000320001.
文摘Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees and,consequently,may threaten human and animal health during outbreaks,causing dermatitis,conjunctivitis and respiratory distress.Although some studies provide detailed information about the setae,particularly those of the pine processionary moth Thaumetopoea pityocampa,there is little knowledge on the morphological traits of the setae and their release by the larvae.In the present study we identify major traits of the setae of 3 species of processionary moth,T.pityocampa,T.pinivora and T.processionea,which are potentially helpful in the understanding of setae dynamics in the environment:(i)diameter and length of setae and(ii)analysis of dynamical properties of the setae in the airborne state.Setae are highly variable in size,with bimodal distribution in T.pityocampa and T.pinivora;in these 2 species,short and long setae are interspersed within the integument fields where they occur.The difference in the seta size has important consequences in dispersion,as smaller setae can spread 5 times further than their bigger counterparts.This information is relevant for a full understanding of the defensive importance of larval setae against natural enemies of the processionary moths,as well for elucidating the importance of the processionary setae as air pollutants,both close to the infested trees and at longer distances.
文摘Water striders are insects living on the water surface, over which they can move very quickly and rarely get wetted. We measured the force of free walking in water striders, using a hair attached to their backs and a 3D strain gauge. The error was calculated by comparing force and data derived from geometry and was estimated as 13%. Females on average were stronger （1.32 mN） than males （0.87 mN）, however, the ratio of force to weight was not significantly different. Compared with other lighter species, Aquarius paludum seems stronger, but the ratio of force to weight is actually lower. A. paludum applies about 0.3 mN.cm^-1 to 0.4 mN.cm 1 with its mid-legs, thus avoiding penetrating the surface tension layer while propelling itself rapidly over the water surface. We also investigated the external morphology with SEM. The body is covered by effectively two layers of macro-and micro-hairs, which renders them hydrophobic. The setae are long （40 μm-60μm） and stiff, being responsible for waterproofing, and the microtrichia are much smaller （〈10μm）, slender, and flexible, holding a bubble over the body when submerged.
基金The authors thank the technicians of the Centro de Microscopia Eletronica(CME)and the histology laboratory of the Department of Zoology,Federal University of Rio Grande do Sul(UFRGS)who assisted with sample preparation,as well as the National Council for Scientific and Technological Development(CNPq)of Brazil.
文摘Egg incubation on the female abdomen is the parental care behavior observed in aeglids,in which eggs are kept adhered to maternal pleopods and maintained,cleaned and aerated.In A.platensis,egg attachment occurs with the aid of pleopodal setae,which are twisted around their axis in the distal region,forming the funiculus,and pleopodal glands,which are responsible for the production of the adhesive substance that seems to be involved in egg fixation to pleopodal setae.Those glands are acini formed by secretory cells arranged concentrically around a central duct,giving them a rosette appearance.Two types of secretory cells were observed,those that produce electron-lucid vesicles and those having electron-dense ones.Both kinds of vesicles are released in a duct whose opening pore is located on the pleopodal surface and constitute the adhesive substance that coats eggs and pleopodal setae,ensuring egg fixation to the female body and maternal care maintenance.This study investigates the internal and external morphology of Aegla platensis pleopods,to understand the egg attachment process and identify the structures involved in this phenomenon.Three microscopy techniques are used:scanning electron microscopy(SEM),transmission electron microscopy(TEM),and optical microscopy(OM).
文摘A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part surface and lateral to the legs which are different in size, arrangement and shape. These setae have different lengths and many thorns on the whole seta. The top ends of these setae stand up without furcations which direct uprightly towards the surface of the touched soil. By the method of removing these setae, getting the insect weight before and after digging into the dung we affirm farther that the setae on the beetle body surface form the anti-stick and non-adherent gentle interface. The soil machines and components made by imitating the gentle body surface of beetles have favorable non-adherent results.
文摘It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00260527).
文摘The anisotropic setae structures of geckos demonstrate a natural anisotropic response to external forces,thereby enabling rapid and repeated attachment and detachment.Considering this biological mechanism,this study proposes an innovative process that harnesses the overcuring of resins in digital light processing(DLP)3D printing to emulate setae structures.The proposed method facilitates the spontaneous fabrication of anisotropic shapes from isotropically modeled geometries.Furthermore,it reduces the number of hierarchical structures typically produced in conventional 3D printing and creates smooth surfaces,thereby enhancing the structural stability for directional adhesion and detachment.The anisotropic structures were processed into functional surfaces through a double-casting method,exhibiting an adhesive strength akin to that of gecko-setae structures while maintaining easy detachment capabilities.Finally,a simple mechanical module was fabricated to directly demonstrate the detachment effect.This study introduces a novel approach to DLP printing for fabricating enhanced anisotropic structures that can be seamlessly integrated with existing 3D printing techniques.By strategically utilizing overcuring,a phenomenon often perceived as a limitation,this study demonstrated its potential to expand the boundaries of next-generation 3D printing technologies.
文摘Summary What is already known about this topic?Redoa leucoscela(R.leucoscela)Collenette(Lepidoptera:Erebidae),releases urticating setae during larval molting.These setae disperse through aquatic and aerial pathways and can trigger allergic reactions upon dermal contact.Clinical manifestations include pruritic dermatitis with stinging sensations and papular lesions;untreated cases may progress to systemic reactions or secondary infections.
基金the Natural Science Foundation of China(Grant Nos.51175281 and 51021064)。
文摘The remarkable ability of geckos to climb and run rapidly on walls and ceilings has recently received considerable interest from many researchers.Significant progress has been made in understanding the attachment and detachment mechanisms and the fabrication of articulated gecko-inspired adhesives and structured surfaces.This article reviews the direct experiments that have investigated the properties of gecko hierarchical structures,i.e.,the feet,toes,setae,and spatulae,and the corresponding models to ascertain the mechanical principles involved.Included in this review are reports on gecko-inspired surfaces and structures with strong adhesion forces,high ratios of adhesion and friction forces,anisotropic hierarchical structures that give rise to directional adhesion and friction,and“intelligent”attachment and detachment motions.
