Attachment performance of stick insects (Phasmatodea) on convex substrates

ABSTRACTPhasmatodea (stick and leaf insects) are herbivorous insects well camouflaged on plant substrates as a result of cryptic masquerade. Also, their close association with plants has allowed them to adapt to different substrate geometries and surface topographies of the plants they imitate. Stick insects are gaining increasing attention in attachment- and locomotion-focused research. However, most studies experimentally investigating stick insect attachment have been performed either on single attachment pads or on flat surfaces. In contrast, curved surfaces, especially twigs or stems of plants, are dominant substrates for phytophagous insects, but not much is known about the influence of curvature on their attachment. In this study, by combining analysis of tarsal usage with mechanical traction and pull-off force measurements, we investigated the attachment performance on curved substrates with different diameters in two species of stick insects with different tarsal lengths. We provide the first quantitative data for forces generated by stick insects on convex curved substrates and show that the curvature significantly influences attachment ability in both species. Within the studied range of substrate curvatures, traction force decreases and pull-off force increases with increasing curvature. Shorter tarsi demonstrate reduced forces; however, tarsus length only has an influence for diameters thinner than the tarsal length. The attachment force generally depends on the number of tarsi/tarsomeres in contact, tarsus/leg orientation and body posture on the surface. Pull-off force is also influenced by the tibiotarsal angle, with higher pull-off force for lower angles, while traction force is mainly influenced by load, i.e. adduction force.

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Nano-Porous Substrates Reduce Beetle Attachment Force

Volume 3: Design; Tribology; Education ◽

10.1115/esda2008-59173 ◽

2008 ◽

Cited By ~ 1

Author(s):

E. Gorb ◽

N. Hosoda ◽

S. Gorb

Keyword(s):

Force Measurement ◽

Glass Plate ◽

Coccinella Septempunctata ◽

Traction Force ◽

Force Transducer ◽

Back Side ◽

Force Measurements ◽

Cell Force ◽

Insect Attachment ◽

Porous Substrates

Traction experiments with the seven-spotted ladybird beetles Coccinella septempunctata (L.) (Coleoptera, Coccinellidae) were carried out to study the influence of surface structure on insect attachment. Force measurements were performed with tethered walking insects using a load cell force transducer. For each beetle, forces were measured on five different substrates: (1) smooth glass plate; (2) smooth solid Al2O3 (sapphire) disc; (3 – 5) porous Al2O3 discs (anodiscs, back side) with the same pore diameter (220 – 235 nm), but different porosity (28, 42 and 51%). Males (N = 10) and females (N = 10) were used in experiments (10 single runs on each surface). Additionally, inversion tests were performed after each traction force measurement. The force ranged from 0.368 to 10.370 mN in males and from 0.514 to 6.262 mN in females. In both sexes, the highest force values were obtained on the smooth glass and sapphire surfaces, where males generated considerably higher forces compared to females. On all three porous substrates, forces were significantly reduced in both males and females, and the only difference for surfaces was obtained between two extremes: anodiscs with the highest (51%) and lowest (28%) porosity. Males produced essentially lower forces than females on anodiscs samples. Experimental insects performed well and showed normal locomotion on both smooth surfaces. On all anodiscs samples, beetles usually were not able to get a grip and slid over the surface, refused to walk and came to a standstill or even turned over on their backs. When substrates were inverted to 90° and 180°, insects were still able to remain attached to both the glass and sapphire samples, but failed on anodiscs. The reduction of insect attachment on anodiscs surfaces is explained by (1) possible absorption of the secretory fluid from insect pads by porous media and (2) effect of surface roughness.

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Slippery pores: anti-adhesive effect of nanoporous substrates on the beetle attachment system

Journal of The Royal Society Interface ◽

10.1098/rsif.2010.0081 ◽

2010 ◽

Vol 7 (52) ◽

pp. 1571-1579 ◽

Cited By ~ 58

Author(s):

E. V. Gorb ◽

N. Hosoda ◽

C. Miksch ◽

S. N. Gorb

Keyword(s):

Glass Plate ◽

Coccinella Septempunctata ◽

Traction Force ◽

Solid Surfaces ◽

Force Measurements ◽

Adhesive Pads ◽

Males And Females ◽

Terminal Structure ◽

Adhesive Effect ◽

Insect Attachment

Traction experiments with adult seven-spotted ladybird beetles Coccinella septempunctata (L.) were carried out to study the influence of surface structure on insect attachment. Force measurements were performed with tethered walking insects, both males and females, on five different substrates: (i) smooth glass plate, (ii) smooth solid Al 2 O 3 (sapphire) disc, and (iii–v) porous Al 2 O 3 discs (anodisc membranes) with the same pore diameter but different porosity. The traction force of beetles ranged from 0.16 to 16.59 mN in males and from 0.32 to 8.99 mN in females. In both sexes, the highest force values were obtained on smooth solid surfaces, where males showed higher forces than females. On all three porous substrates, forces were significantly reduced in both males and females, and the only difference within these surfaces was obtained between membranes with the highest and lowest porosity. Males produced essentially lower forces than females on porous samples. The reduction in insect attachment on anodisc membranes may be explained by (i) possible absorption of the secretion fluid from insect adhesive pads by porous media and/or (ii) the effect of surface roughness. Differences in attachment between males and females were probably caused by the sexual dimorphism in the terminal structure of adhesive setae.

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Reduction in Insect Attachment Caused by Different Nanomaterials Used as Particle Films (Kaolin, Zeolite, Calcium Carbonate)

Sustainability ◽

10.3390/su13158250 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8250

Author(s):

Gianandrea Salerno ◽

Manuela Rebora ◽

Silvana Piersanti ◽

Valerio Saitta ◽

Alexander Kovalev ◽

...

Keyword(s):

Calcium Carbonate ◽

Traction Force ◽

Good Alternative ◽

Behavioral Experiments ◽

Linear Speed ◽

Carbonate Particle ◽

Attachment Ability ◽

Insect Attachment ◽

Cuticular Surface ◽

Calcium Carbonate Particle

In the present investigation, we compared the reduction in attachment ability of the southern green stinkbug Nezara viridula (Hemiptera: Pentatomidae) to glass induced by three different nanoparticle (kaolin, zeolite, and calcium carbonate) films. Using traction force experiments, behavioral experiments, and scanning electron microscopy observations, we analyzed the insect attachment ability and linear speed on untreated and treated glass with the three particle films. The three nanomaterials strongly reduced insect attachment ability mainly owing to contamination of attachment pads. The ability to reduce insect attachment was different for the three tested particle films: kaolin and zeolite induced a significantly higher reduction in N. viridula safety factor than calcium carbonate. The coating of the surface was more uniform and compact in kaolin and zeolite compared to calcium carbonate particle film. Moreover, kaolin and zeolite particles can more readily adhere to N. viridula attachment devices, whereas calcium carbonate particles appeared less adherent to the cuticular surface compared to the two aluminosilicate (kaolin and zeolite) particles. Only the application of kaolin reduced insect linear speed during locomotion. Nanoparticle films have a great potential to reduce insect attachment ability and represent a good alternative to the use of insecticides for the control of pentatomid bugs and other pest insects.

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Intersegmental Coordination of Walking Movements in Stick Insects

Journal of Neurophysiology ◽

10.1152/jn.00727.2004 ◽

2005 ◽

Vol 93 (3) ◽

pp. 1255-1265 ◽

Cited By ~ 33

Author(s):

Björn Ch. Ludwar ◽

Marie L. Göritz ◽

Joachim Schmidt

Keyword(s):

Motor Pattern ◽

Central Pattern Generators ◽

Stick Insect ◽

Neural Mechanisms ◽

Chordotonal Organ ◽

Adjacent Segment ◽

Body Segments ◽

Stick Insects ◽

Pattern Generators ◽

Leg Movements

Locomotion requires the coordination of movements across body segments, which in walking animals is expressed as gaits. We studied the underlying neural mechanisms of this coordination in a semi-intact walking preparation of the stick insect Carausius morosus. During walking of a single front leg on a treadmill, leg motoneuron (MN) activity tonically increased and became rhythmically modulated in the ipsilateral deafferented and deefferented mesothoracic (middle leg) ganglion. The pattern of modulation was correlated with the front leg cycle and specific for a given MN pool, although it was not consistent with functional leg movements for all MN pools. In an isolated preparation of a pair of ganglia, where one ganglion was made rhythmically active by application of pilocarpine, we found no evidence for coupling between segmental central pattern generators (CPGs) that could account for the modulation of MN activity observed in the semi-intact walking preparation. However, a third preparation provided evidence that signals from the front leg's femoral chordotonal organ (fCO) influenced activity of ipsilateral MNs in the adjacent mesothoracic ganglion. These intersegmental signals could be partially responsible for the observed MN activity modulation during front leg walking. While afferent signals from a single walking front leg modulate the activity of MNs in the adjacent segment, additional afferent signals, local or from contralateral or posterior legs, might be necessary to produce the functional motor pattern observed in freely walking animals.

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Pathological and Microbiological Study of Mortality in a Captive Breeding Colony of the Endangered Lord Howe Island Stick Insect (Dryococelus australis)

Veterinary Pathology ◽

10.1177/0300985818766210 ◽

2018 ◽

Vol 55 (5) ◽

pp. 719-730

Author(s):

Christine Bayley ◽

Christina Cheng ◽

Michael Lynch

Keyword(s):

Captive Breeding ◽

Positive Culture ◽

Opportunistic Pathogen ◽

Stick Insect ◽

Innate Immune ◽

Breeding Colony ◽

Lord Howe Island ◽

Stick Insects ◽

Gross Lesions ◽

Increased Susceptibility

The authors describe pathological and microbiological features of mortalities in a captive breeding colony of Lord Howe Island stick insects ( Dryococelus australis) over a period of 18 months. There were 2 peaks of mortality in this period. In the first, insects presented dead with minimal premonitory signs of illness. In the second, affected insects were ataxic with contracted limbs and inability to climb or right themselves. Gross lesions were uncommon but included pigmented plaques on the gut and cloacal prolapse. Histological lesions in both outbreaks indicated a cellular innate immune response including nodulation characterized by Gram-negative bacterial bacilli entrapped within nodules of pigmented hemocytes, and melanization characterized by melanin within hemocyte nodules and around bacteria. Hemolymph culture findings varied and often yielded a mixed growth. Pure growth of Serratia marcescens was cultured in 44% of animals in Outbreak 1, while pure growth of Pseudomonas aeruginosa was cultured in 30% of animals in Outbreak 2. Cases with S. marcescens-positive culture often showed inflammation at the foregut-midgut junction. The frequency of mixed bacterial culture results did not allow firm conclusions about causality to be made, and may indicate primary bacterial infection or increased susceptibility to hemolymph colonization with an opportunistic pathogen. These findings highlight the utility of histopathology combined with ancillary testing when investigating mortality in captive insect colonies.

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Descending octopaminergic neurons modulate sensory-evoked activity of thoracic motor neurons in stick insects

Journal of Neurophysiology ◽

10.1152/jn.00196.2019 ◽

2019 ◽

Vol 122 (6) ◽

pp. 2388-2413 ◽

Cited By ~ 4

Author(s):

Thomas Stolz ◽

Max Diesner ◽

Susanne Neupert ◽

Martin E. Hess ◽

Estefania Delgado-Betancourt ◽

...

Keyword(s):

Motor Neurons ◽

Stick Insect ◽

Neuron Activity ◽

Sense Organs ◽

Descending Neurons ◽

Walking Activity ◽

Stick Insects ◽

Evoked Activity ◽

Sensory Evoked ◽

Stimulation Of

Neuromodulatory neurons located in the brain can influence activity in locomotor networks residing in the spinal cord or ventral nerve cords of invertebrates. How inputs to and outputs of neuromodulatory descending neurons affect walking activity is largely unknown. With the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and immunohistochemistry, we show that a population of dorsal unpaired median (DUM) neurons descending from the gnathal ganglion to thoracic ganglia of the stick insect Carausius morosus contains the neuromodulatory amine octopamine. These neurons receive excitatory input coupled to the legs’ stance phases during treadmill walking. Inputs did not result from connections with thoracic central pattern-generating networks, but, instead, most are derived from leg load sensors. In excitatory and inhibitory retractor coxae motor neurons, spike activity in the descending DUM (desDUM) neurons increased depolarizing reflexlike responses to stimulation of leg load sensors. In these motor neurons, descending octopaminergic neurons apparently functioned as components of a positive feedback network mainly driven by load-detecting sense organs. Reflexlike responses in excitatory extensor tibiae motor neurons evoked by stimulations of a femur-tibia movement sensor either are increased or decreased or were not affected by the activity of the descending neurons, indicating different functions of desDUM neurons. The increase in motor neuron activity is often accompanied by a reflex reversal, which is characteristic for actively moving animals. Our findings indicate that some descending octopaminergic neurons can facilitate motor activity during walking and support a sensory-motor state necessary for active leg movements. NEW & NOTEWORTHY We investigated the role of descending octopaminergic neurons in the gnathal ganglion of stick insects. The neurons become active during walking, mainly triggered by input from load sensors in the legs rather than pattern-generating networks. This report provides novel evidence that octopamine released by descending neurons on stimulation of leg sense organs contributes to the modulation of leg sensory-evoked activity in a leg motor control system.

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Traction force measurements on male Strepsiptera (Insecta) revealed higher forces on smooth compared with hairy substrates

Journal of Experimental Biology ◽

10.1242/jeb.223784 ◽

2020 ◽

Vol 223 (18) ◽

pp. jeb223784

Author(s):

Hans Pohl ◽

Elena V. Gorb ◽

Stanislav N. Gorb

Keyword(s):

Van Der Waals ◽

Traction Force ◽

Capillary Forces ◽

Van Der Waals Interactions ◽

Smooth Surfaces ◽

Mechanical Interlocking ◽

Force Measurements ◽

Caudal Direction ◽

Primary Contribution

ABSTRACTThe aim of this study was to find out how strongly the parasitic insect Stylopsovinae, which has tarsi equipped with tenent hairs and lacking claws, attaches to different substrates. We investigated adhesion of male S. ovinae to the abdomen of its hymenopteran host (Andrena vaga), the hairier abdomen of a Bombus sp. and two artificial smooth reference surfaces with different degrees of hydrophilicity. In our experiments, the male S. ovinae developed significantly higher forces on smooth surfaces. However, the forces were significantly lower on all the hymenopteran surfaces used in the experiment. The absence of anisotropy in the force grip in cranial/caudal direction relative to the host might indirectly indicate that S. ovinae generate forces by adhesion rather than mechanical interlocking with the host hairs. The tolerance of the attachment system of S. ovinae to the substrate chemistry might be explained by the primary contribution of van der Waals interactions and not capillary forces to adhesion in S. ovinae.

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Load Signals Assist the Generation of Movement-Dependent Reflex Reversal in the Femur–Tibia Joint of Stick Insects

Journal of Neurophysiology ◽

10.1152/jn.00625.2006 ◽

2006 ◽

Vol 96 (6) ◽

pp. 3532-3537 ◽

Cited By ~ 25

Author(s):

Turgay Akay ◽

Ansgar Büschges

Keyword(s):

Time Course ◽

Stick Insect ◽

Motor Output ◽

Chordotonal Organ ◽

Frequency Of Occurrence ◽

Stick Insects ◽

Extensor Motoneuron ◽

Motoneuron Activity ◽

First Time ◽

Stimulation Of

Reinforcement of movement is an important mechanism by which sensory feedback contributes to motor control for walking. We investigate how sensory signals from movement and load sensors interact in controlling the motor output of the stick insect femur–tibia (FT) joint. In stick insects, flexion signals from the femoral chordotonal organ (fCO) at the FT joint and load signals from the femoral campaniform sensilla (fCS) are known to individually reinforce stance-phase motor output of the FT joint by promoting flexor and inhibiting extensor motoneuron activity. We quantitatively compared the time course of inactivation in extensor tibiae motoneurons in response to selective stimulation of fCS and fCO. Stimulation of either sensor generates extensor activity in a qualitatively similar manner but with a significantly different time course and frequency of occurrence. Inactivation of extensor motoneurons arising from fCS stimulation was more reliable but more than threefold slower compared with the extensor inactivation in response to flexion signals from the fCO. In contrast, simultaneous stimulation of both sense organs produced inactivation in motoneurons with a time course typical for fCO stimulation alone, but with a frequency of occurrence characteristic for fCS stimulation. This increase in probability of occurrence was also accompanied by a delayed reactivation of the extensor motoneurons. Our results indicate for the first time that load signals from the leg affect the processing of movement-related feedback in controlling motor output.

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