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A) The anatomy of larval Manduca sexta (fifth instar). Caterpillars generally have this body plan but the number of prolegs can vary among species. The body is soft except for the head capsule, mandibles, thoracic legs and the crochets on the tips of the prolegs. (B) Schematic cross section of a caterpillar on a dowel. COM = centre of mass.
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Most species of caterpillar move around by inching or crawling. Their ability to navigate in branching three-dimensional structures makes them particularly interesting biomechanical subjects. The mechanism of inching has not been investigated in detail, but crawling is now well understood from studies on caterpillar neural activity, dynamics and st...
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... several orders of magnitude from hatchling to prepupa. During this period they moult several times, each stage between moults being an instar. Between moults their soft cuticle can stretch extensively. The only hard cuticle is found on the mandibles, spiracles, the thoracic legs, the crochets (hooks) at the tip of the prolegs and the head capsule (Fig. 1A). This overall body softness has important consequences for locomotion. Because muscles are connected to the body wall, their activation can deform the body without leading to locomotory movement. This is a highly energy-inefficient way to move: the cost of transport for gypsy moth caterpillars (Lymantria dispar L.) (Erebidae) is 4.5 ...
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... have a soft cylindrical body, with three pairs of stiff-jointed thoracic legs and 2-5 pairs of soft leg-like structures on the abdomen called prolegs (Fig. 1A). Apart from this overall body plan, caterpillars differ dramatically in body shape and size and hence exhibit different strategies for forward locomotion. For example, inching behaviour in which the posterior legs are pulled forward to grip the substrate just behind the thoracic segments (each 'step' is therefore almost one body length ...
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... pairs of legs are lifted simultaneously. This has been observed in both Manduca sexta and Pleuroptya ruralis (Brackenbury, 1999;van Griethuijsen & Trimmer, 2009). In normal anterograde crawling, speed seems to be limited by the need for stability. Because of the location of the prolegs under the body, and the relatively elevated centre of mass (Fig. 1B), caterpillars run the risk of rolling sideways and hence a high duty factor is desirable. Brackenbury (1999) noted that if the legs and body segments cannot be lifted faster, then decreasing the timing between each anterograde wave of steps becomes the only possible mechanism to increase speed but this will result in increased ...
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... may also be used to describe the entire terminal body segment) functions in the same way as the other prolegs although, at least in Manduca sexta, cannot be shortened to the same extent. However the TP can pivot much more that the other prolegs because there is no attachment point posterior or directly anterior to it (Trimmer & Issberner, 2007) (Fig. 1A). The TP can also be referred to as ...
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... use the strong passive grip of their crochets regardless of orientation. This facilitates retaining hold of a plant moved by wind and resistance to removal by a predator. The prolegs are located underneath the body with a relatively short distance between them, while the centre of mass is located relatively high above the legs (Fig. 1B). This is a mechanically unstable configuration when the caterpillar is right side up. Without a strong grip the caterpillar would be susceptible to toppling over (Brackenbury, 1999). Furthermore, caterpillars such as Manduca sexta need a strong grip to support their considerable weight when they are on the underside of leaves (field ...
Citations
... The primary researcher has checked the reliability and validity of the questionnaires. The Cronbach alpha value was above 0.65, The Cronbach value above is acceptable (Griethuijsen et al., 2014, Taber KS, 2018) [28,27] . The confirmatory analysis shows that the CMIN/DF value is less than 1.749 which was an acceptable fit ≤ 3 indicates an acceptable fit (Kline, 1998) [18] . ...
There is a lack of studies on training age and the effect of training age on psychological characteristics no study indicates the difference between training age on emotion regulation and achievement goal and anxiety in sports. In this study, we examined the difference between different training ages on emotional regulation, achievement goals and Sports performance Anxiety, as well as emotion regulation, achievement goal and anxiety as a predictor of Training age. To collect data for this research, the "Emotion Regulation Questionnaire (ERQ; Gross & John, 2003)", "Achievement Goal: Elliot and McGregor's (2001)" and "Sport Performance Anxiety SAS-2 were used together with a personal information form. Cronbach Alpha, Confirmatory factor analysis, One-way ANOVA, and leaner regression analysis were computed. The data were obtained from a total of 201 (97 male and 104 female) Indian interuniversity-level judo players divided into 3 training age groups 1-5,6-10 and 11-15 year training groups. The validity and reliability of the data were constructed. Mastery avoidance, Performance Approach, and Performance avoidance show significant differences in training age groups. 11-15 years training age group shows higher Achievement goal as well as higher sports performance anxiety. 6-10 year training age groups show higher emotion regulation. Performance avoidance only positively predicts training age.
... This study aims to develop the digital design and fabrication of kinematic chains related to the biomechanics of the 2 groups of caterpillars [23,24], which is a milestone for creating robots or machines that can perform tasks with flexibility-dexterity and developing features for being able to change/adjust the modular components that can be assembled or replaced [25,26]. ...
... For example, some primitive insects, such as springtails (Archaeognatha) and silverfish (Zygentoma), develop a set of styli and eversible vesicles on their abdominal segments (Machida, 1981). In various pterygote (winged) insects, such as the glossatan Lepidoptera and symphytan Hymenoptera, the larvae regain several pairs of abdominal appendages (prolegs) for locomotion (Hua et al., 2020;van Griethuijsen & Trimmer, 2014;Williamson, 2009). However, the molecular mechanisms underlying such morphological diversification remain largely unclear. ...
The abdominal appendages of larval insects have a complex evolutionary history of gain and loss, but the regulatory mechanisms underlying the abdominal appendage development remain largely unclear. Here, we investigated the embryogenesis of abdominal prolegs in the scorpionfly Panorpa liui Hua (Mecoptera: Panorpidae) using in situ hybridization and parental RNA interference. The results show that RNAi‐mediated knockdown of Ultrabithorax ( Ubx ) led to a homeotic transformation of the first abdominal segment (A1) into the third thoracic segment (T3) and changed the distributions of the downstream target Distal‐less ( Dll ) expression but did not affect the expression levels of Dll . Knockdown of abdominal‐A ( abd‐A ) resulted in malformed segments, abnormal prolegs and disrupted Dll expression. The results demonstrate that the gene Ubx maintains an ancestral role of modulating A1 appendage fate without preventing Dll initiation, and a secondary adaptation of abd‐A evolves the ability to specify abdominal segments and proleg identity. We conclude that changes in abdominal Hox gene expression and their target genes regulate abdominal appendage morphology during the evolutionary course of holometabolous larvae.
... Locomotion is a fundamental behaviour in the Animal Kingdom. There is great diversity in how it is accomplished, from the modification of torque angles in rigid bodied animals (Audu et al., 2007 ) to a diverse array of peristalses in limbed (reviewed in van Griethuijsen & Trimmer, 2014 ) and limbless soft-bodied animals (Berrigan & Pepin, 1995 ). Key to these different strategies is one unifying characteristic: action against a substrate or fluid produces forces, thereby translating the body in space. ...
During locomotion, soft-bodied terrestrial animals solve complex control problems at substrate interfaces, but our understanding of how they achieve this without rigid components remains incomplete. Here, we develop new all-optical methods based on optical interference in a deformable substrate to measure ground reaction forces (GRFs) with micrometre and nanonewton precision in behaving Drosophila larvae. Combining this with a kinematic analysis of substrate interfacing features, we shed new light onto the biomechanical control of larval locomotion. Crawling in larvae measuring ∼1 mm in length involves an intricate pattern of cuticle sequestration and planting, producing GRFs of 1-7 μN. We show that larvae insert and expand denticulated, feet-like structures into substrates as they move, a process not previously observed in soft bodied animals. These ‘protopodia’ form dynamic anchors to compensate counteracting forces. Our work provides a framework for future biomechanics research in soft-bodied animals and promises to inspire improved soft-robot design.
... 44 Furthermore, multifocal infection of dorso-ventral muscles, dorsal and ventral longitudinal muscles, and intrinsic and extrinsic leg muscles will cause asymmetrical and asynchronous locomotion that generates swirling, rolling, and nonambulatory larva rather than paralysis and/or ataxia, which are terms usually associated with neurological impairment. 5,42 Respiration impairment is due to skeletal muscle lesions that interfere with larval breathing by affecting convective gas transport, which variably depends on muscle contractions. 3,29,30 In addition, the death of tracheolar epithelial cells may further impair larval respiration by interfering with O 2 /CO 2 transport and exchange. ...
Mealworms are one of the most economically important insects in large-scale production for human and animal nutrition. Densoviruses are highly pathogenic for invertebrates and exhibit an extraordinary level of diversity which rivals that of their hosts. Molecular, clinical, histological, and electron microscopic characterization of novel densovirus infections is of utmost economic and ecological importance. Here, we describe an outbreak of densovirus with high mortality in a commercial mealworm (Tenebrio molitor) farm. Clinical signs included inability to prehend food, asymmetric locomotion evolving to nonambulation, dehydration, dark discoloration, and death. Upon gross examination, infected mealworms displayed underdevelopment, dark discoloration, larvae body curvature, and organ/tissue softness. Histologically, there was massive epithelial cell death, and cytomegaly and karyomegaly with intranuclear inclusion (InI) bodies in the epidermis, pharynx, esophagus, rectum, tracheae, and tracheoles. Ultrastructurally, these InIs represented a densovirus replication and assembly complex composed of virus particles ranging from 23.79 to 26.99 nm in diameter, as detected on transmission electron microscopy. Whole-genome sequencing identified a 5579-nucleotide-long densovirus containing 5 open reading frames. A phylogenetic analysis of the mealworm densovirus showed it to be closely related to several bird- and bat-associated densoviruses, sharing 97% to 98% identity. Meanwhile, the nucleotide similarity to a mosquito, cockroach, and cricket densovirus was 55%, 52%, and 41%, respectively. As this is the first described whole-genome characterization of a mealworm densovirus, we propose the name Tenebrio molitor densovirus (TmDNV). In contrast to polytropic densoviruses, this TmDNV is epitheliotropic, primarily affecting cuticle-producing cells.
... Our study found that the average body weight of FAW larvae increased by nearly 100 times from the 1st to the 3rd instars, and then again from the 3rd to the 6th instars. Furthermore, as larvae develop, they acquire more tarsal hooks on their legs and prolegs, which improves their crawling ability [44]. For example, FAW 1st instars are small in size and have few tarsal hooks, whereas the 3rd-4th instar larvae have 10-15 hooks, and the 5th-6th instar larvae have 17-18 hooks [45]. ...
The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a major pest of corn worldwide. FAW larval dispersal is an important life strategy that influences FAW population distribution in corn fields and subsequent plant damage. We studied FAW larval dispersal in the laboratory with sticky plates placed around the test plant and a unidirectional airflow source. Crawling and ballooning were the main dispersal means of FAW larvae both within and between corn plants. All larval instars (1st–6th) could disperse by crawling, with crawling being the only dispersal mechanism for 4th–6th instars. By crawling, FAW larvae could reach all aboveground parts of a corn plant as well as adjacent corn plants where leaves overlapped. Ballooning was used primarily by 1st-3rd instar larvae, and the proportion of these larvae that used ballooning decreased with age. Ballooning was largely governed by the larva’s interaction with airflow. Airflow influenced the direction and distance of larval ballooning. With an airflow speed of about 0.05 m/s, 1st instars could travel up to 196 cm from the test plant, indicating that long-distance FAW larval dispersal depends on ballooning. These results increase our understanding of FAW larval dispersal and provide scientific information for the development of FAW monitoring and control strategies.
... Friction management is central to efficient crawling over complex terrains [2]. Biological solutions to adjust the friction include anchoring with prolegs in caterpillars [3] and setae in earthworm [4], and orienting ventral scales in snakes [5]. ...
... They perform gait by sequentially contracting segments and bending them into an omega (U) shape. [4][5][6] Such motion is beneficial for certain movements such as twisting the body or going through narrow gaps. Moreover, caterpillars have a completely soft body without rigid components, which allows them to interact and adapt to changing environments. ...
The soft structure of creatures without a rigid internal skeleton can easily adapt to any atypical environment. In the same context, robots with soft structures can change their shape to adapt to complex and varied surroundings. In this study, we introduce a caterpillar-inspired soft crawling robot with a fully soft body. The proposed crawling robot consists of soft modules based on an electrohydraulic actuator, a body frame, and contact pads. The modular robotic design produces deformations similar to the peristaltic crawling behavior of caterpillars. In this approach, the deformable body replicates the mechanism of the anchor movement of a caterpillar by sequentially varying the friction between the robot contact pads and the ground. The robot carries out forward movement by repeating the operation pattern. The robot has also been demonstrated to traverse slopes and narrow crevices.
... In a complicated environment, inchworms, which are arthropods, may travel ahead and jump over barriers. Their soft bodies and strong muscles contribute to their agility and resilience [1]. They have served as an inspiration for the creation of bionic soft robots that can carry out difficult detecting tasks in a chaotic and unpredictable environment [2]. ...
To produce multi-modal mobility in complicated situations is a significant issue for soft robots. In this study, we show the conception, construction, and operation of an inchworm-impersonating dielectric elastomer-activated soft robot. The robot is small and lightweight, weighing only 3.5 g, and measuring an overall 110 mm by 50 mm by 60 mm (length, width, and height). The three mobility modes for the robot are each equipped with a detailed mechanism. When the excitation voltage is 5 kV, the robot runs forward under a frequency of stimulation of 1–9 Hz, and its direction of motion changes to a backwards motion at >10 Hz. When the excitation voltage of 5.5 kV is applied to the robot, the robot runs forward at 1–12 Hz frequency and moves in the opposite direction at 13 Hz, reaching the fastest reverse speed of 240 mm/s. When the excitation voltage rises to 6 kV, the robot reaches its fastest running speed of 270 mm/s at 14 Hz. Motivated by high voltage and high duty cycle, the robot can jump over obstacles of 5 mm. In order to assess the performance of backward running, the speed achieved by the robot under a 30% duty cycle and a 50% duty cycle was compared, as well as the speed of the robot with or without the use of a counterweight. The robot has a simpler design and construction than earlier soft robots of the same kind, as well as a quicker speed, a wider variety of movement modes, and other notable advantages.
... As shown in Fig. 2a, a silkworm-like gait is selected and improved in CCRobot-V. Although an inchworm-like gait offers more flexibility and accessibility than a silkwormlike gait in terms of adapting to complex environments, silkworms use their "abdominal legs" to support their multisegmented bodies [25] [26], which is more suitable for a cable-climbing scenario that requires high payload ability and durability. Similar to the silkworm's multi-segmented bodies, we creatively split CCRobot-V into several parts and connect them by adopting a wire-driven transmission system, it removes the stiffness requirement of the robot's body and drastically reduces the robot's body mass. ...
