Search

The insect cuticle, which serves as both a protective barrier and an efficient lever system for locomotion, is an extracellular matrix primarily composed of chitin and protein. The cuticle protein CPCFC characterized by a “CFC” motif containing 2 Cys split by the insertion of 5 residues is distributed across most insect species and specifically localized in the hard part of the cuticle. However, their physiological function is not fully understood. Here, we report 2 CPCFC proteins, TcCPCFC1 and TcCPCFC2, derived from the Coleopteran insect Tribolium castaneum. We revealed that TcCPCFC1 and TcCPCFC2 were predominantly expressed during the larval and adult stages of T. castaneum, respectively. The transcription downregulation of TcCPCFC1 significantly decreased the modulus and toughness of the elytral cuticle. We found that TcCPCFC proteins have high binding affinity to chitin. We cloned and produced recombinant TcCPCFC proteins and demonstrated that the addition of TcCPCFC proteins to chitin hydrogel greatly enhanced the hydrogel's modulus and toughness by forming denser chitin fibrous networks. Our findings reveal the functional role of CPCFC proteins in enhancing mechanical properties of insect cuticle, and we validate this process in vitro, and offer a protein candidate for fabrication of advanced chitin‐based materials. [ABSTRACT FROM AUTHOR]

Circadian rhythms are self‐sustained endogenous oscillations that are found in all living organisms. In insects, circadian rhythms control a wide variety of behavioral and physiological processes, including feeding, locomotion, mating, and metabolism. While the role of circadian rhythms in adult insects is well‐understood, it is largely unexplored in larvae. This study investigates the potential for larval synchronized activity in the red flour beetle (Tribolium castaneum), a species exhibiting solitary and aggregation phases. We hypothesized that, similar to adults, larvae would exhibit a daily activity pattern governed by an endogenous circadian clock. We further predicted that the transition between the solitary and gregarious phases extends to unique temporal activity patterns. Our results revealed unique timekeeper gene expression in larvae, leading to a distinct daily rhythm characterized by nocturnal activity. Cues indicating on potential cannibalism did not change daily activity peak. However, the absence of these cues significantly reduced the proportion of rhythmic larvae and led to higher variation in peak activity, highlighting the crucial role of social interactions in shaping their rhythmicity. This study sheds light on the evolution and function of larval synchronization in group‐living insects, offering novel insights into this complex behavior. [ABSTRACT FROM AUTHOR]

Blow flies (Diptera: Calliphoridae) are arguably the most important providers of an estimate of minimum post‐mortem interval in forensic investigations. They usually undergo a post‐feeding dispersal from the body. While previous studies have looked at dispersal of groups of larvae, recording the dispersal activity of individual larvae has not previously been demonstrated. A servosphere was used here to record the speed, directionality and phototaxis of individual post‐feeding larvae of two species of blow fly on a smooth plastic surface over time. The servosphere rotates to compensate for the movement of an insect placed at its apex, thereby enabling its unimpeded locomotion in any direction to be studied and behavioural changes to external stimuli recorded. To our knowledge, the servosphere has not previously been used to study apodous insects. The objective of our study was to compare dispersal behaviour of Calliphora vicina Robineau‐Desvoidy and Protophormia terraenovae (Robineau‐Desvoidy), both common primary colonisers of human and animal cadavers, but showing different post‐feeding dispersal strategies. Larvae of C. vicina generally disperse from the body while those of P. terraenovae remain on or close to the body. Our aims were to study (1) changes in dispersal speed over a 1‐h period; (2) changes in dispersal speed once a day for 4 days, between the end of feeding and onset of pupariation; and (3) response of dispersing larvae to light. We demonstrated that (1) the movement of three C. vicina larvae tracked for 1 continuous hour on 1 day slowed from an average of 3 to <1.7 mms−1; (2) the average speed of 20 larvae of C. vicina (4.08 mms−1) recorded for 5 min once per day over a 4‐day period between onset of dispersal and pupariation was significantly greater than that of P. terraenovae (2.36 mms−1; p < 0.0001), but that speed of both species increased slightly over the 4 days; (3) the responses of larvae of C. vicina to changes in light direction from the four cardinal directions of the compass, showed that they exhibited a strong negative phototactic response within 5 s, turning to move at approximately 180° away from the new light position. While conducted to observe larval calliphorid post‐feeding behaviour, the results of this proof of concept study show that apodous insects can be studied on a servosphere to produce both qualitative and quantitative data. [ABSTRACT FROM AUTHOR]

Several studies comparing primate locomotion under lab versus field conditions have shown the importance of implementing both types of studies, as each has their advantages and disadvantages. However, three‐dimensional (3D) motion capture of primates has been challenging under natural conditions. In this study, we provide a detailed protocol on how to collect 3D biomechanical data on primate leaping in their natural habitat that can be widely implemented. To record primate locomotion in the dense forest we use modified GoPro Hero Black cameras with zoom lenses that can easily be carried around and set up on tripods. We outline details on how to obtain camera calibrations at greater heights and how to process the collected data using the MATLAB camera calibration app and the motion tracking software DLTdv8a. We further developed a new MATLAB application “WildLeap3D” to generate biomechanical performance metrics from the derived x, y, z coordinates of the leaps. We provide details on how to collect data on support diameter, compliance, and orientation, and combine these with the jumps to study locomotor performance in an ecological context. We successfully reconstructed leaps of wild primates in the 3D space under natural conditions and provided data on four representative leaps. We provide exemplar data on primate velocity and acceleration during a leap and show how our protocol can be used to analyze segmental kinematics. This study will help to make motion capture of freely moving animals more accessible and help further our knowledge about animal locomotion and movement. [ABSTRACT FROM AUTHOR]

Objectives: Calcaneal external shape differs among nonhuman primates relative to locomotion. Such relationships between whole‐bone calcaneal trabecular structure and locomotion, however, have yet to be studied. Here we analyze calcaneal trabecular architecture in Gorilla gorilla gorilla, Gorilla beringei beringei, and G. b. graueri to investigate general trends and fine‐grained differences among gorilla taxa relative to locomotion. Materials and methods: Calcanei were micro‐CT scanned. A three‐dimensional geometric morphometric sliding semilandmark analysis was carried out and the final landmark configurations used to position 156 volumes of interest. Trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and bone volume fraction (BV/TV) were calculated using the BoneJ plugin for ImageJ and MATLAB. Non‐parametric MANOVAs were run to test for significant differences among taxa in parameter raw values and z‐scores. Parameter distributions were visualized using color maps and summarized using principal components analysis. Results: There are no significant differences in raw BV/TV or Tb.Th among gorillas, however G. b. beringei significantly differs in z‐scores for both parameters (p = <0.0271). All three taxa exhibit relatively lower BV/TV and Tb.Th in the posterior half of the calcaneus. This gradation is exacerbated in G. b. beringei. G. b. graueri significantly differs from other taxa in Tb.Sp z‐scores (p < 0.001) indicating a different spacing distribution. Discussion: Relatively higher Tb.Th and BV/TV in the anterior calcaneus among gorillas likely reflects higher forces associated with body mass (transmitted through the subtalar joint) relative to forces transferred through the posterior calcaneus. The different Tb.Sp pattern in G. b. graueri may reflect proposed differences in foot positioning during locomotion. [ABSTRACT FROM AUTHOR]

Objectives: Integration reflects the level of coordinated variation of the phenotype. The integration of postcranial elements can be studied from a functional perspective, especially with regards to locomotion. This study investigates the link between locomotion, femoral structural properties, and femur‐pelvis complex morphology. Materials and Methods: We measured (1) morphological integration between femoral and pelvic morphologies using geometric morphometrics, and (2) covariation between femoral/pelvic morphologies and femoral diaphyseal cross‐sectional properties, which we defined as morpho‐structural integration. Morphological and morpho‐structural integration patterns were measured among humans (n = 19), chimpanzees and bonobos (n = 16), and baboons (n = 14), whose locomotion are distinct. Results: Baboons show the highest magnitude of morphological integration and the lowest of morpho‐structural integration. Chimpanzees and bonobos show intermediate magnitude of morphological and morpho‐structural integration. Yet, body size seems to have a considerable influence on both integration patterns, limiting the interpretations. Finally, humans present the lowest morphological integration and the highest morpho‐structural integration between femoral morphology and structural properties but not between pelvic morphology and femur. Discussion: Morphological and morpho‐structural integration depict distinct strategies among the samples. A strong morphological integration among baboon's femur‐pelvis module might highlight evidence for long‐term adaptation to quadrupedalism. In humans, it is likely that distinct selective pressures associated with the respective function of the pelvis and the femur tend to decrease morphological integration. Conversely, high mechanical loading on the hindlimbs during bipedal locomotion might result in specific combination of structural and morphological features within the femur. [ABSTRACT FROM AUTHOR]

Objectives: An accident during arboreal locomotion can lead to risky falls, but it remains unclear that the extent to which primates, as adept arborealists, change their locomotion in response to the perceived risk of moving on high supports in the tree canopy. By using more stable forms of locomotion on higher substrates, primates might avoid potentially fatal consequences. Materials and Methods: Using high‐speed cameras, we recorded the quadrupedal locomotion of four wild lemur species—Eulemur rubriventer, Eulemur rufifrons, Hapalemur aureus, and Lemur catta (N = 113 total strides). We quantified the height, diameter, and angular orientation of locomotor supports using remote sensors and tested the influence of support parameters on gait kinematics, specifically predicting that in response to increasing substrate height, lemurs would decrease speed and stride frequency, but increase stride length and the mean number of supporting limbs. Results: Lemurs did not adjust stride frequency on substrates of varying height. Adjustments to speed, stride length, and the mean number of supporting limbs in response to varying height often ran counter to predictions. Only E. rubriventer decreased speed and increased the mean number of supporting limbs on higher substrates. Discussion: Results suggest that quadrupedal walking is a relatively safe form of locomotion for lemurs, requiring subtle changes in gait to increase stability on higher—that is, potentially riskier—substrates. Continued investigation of the impact of height on locomotion will be important to determine how animals assess risk in their environment and how they choose to use this information to move more safely. Research Highlights: Substrate height can increase the risk of injury after a fall.Lemurs make subtle and variable adjustments to gait in response to substrate height.Substrate height will be important to include in future studies of wild primate locomotion. [ABSTRACT FROM AUTHOR]

The moth fly, Clogmia albipunctata, is a common synanthropic insect with a worldwide range that lives in nearly any area with moist, decaying organic matter. These habitats comprise both smooth, slippery substrates (e.g., bathroom drains) and heterogeneous, bumpy ground (e.g., soil in plant pots). By using terrain of varying levels of roughness, we focus specifically on how substrate roughness at the approximate size scale of the organism affects kinematics and coordination in adult moth flies. Finally, we compare and contrast our characterizations of locomotion in C. albipunctata with previous work of insect walking in naturalistic environments. [ABSTRACT FROM AUTHOR]

Jumping requires high actuation power for achieving high speed in a short time. Especially, organisms and robots at the insect scale jump in order to overcome size limits on the speed of locomotion. As small jumpers suffer from intrinsically small power output, efficient jumpers have devised various ingenuous schemes to amplify their power release. Furthermore, semi‐aquatic jumpers have adopted specialized techniques to fully exploit the reaction from water. We review jumping mechanisms of natural and robotic insects that jump on the ground and the surface of water, and compare the performance depending on their scale. We find a general trend that jumping creatures maximize jumping speed by unique mechanisms that manage acceleration, force, and takeoff duration under the constraints mainly associated with their size, shape, and substrate. [ABSTRACT FROM AUTHOR]

The modular organization of tetrapod paired limbs and girdles, influenced by the expression of Hox genes is one of the primary driving forces of the evolution of animal locomotion. The increased morphological diversification of the paired limbs is correlated with reduced between‐limb covariation, while correlation within the elements is usually higher than between the elements. The tailed amphibians, such as Lissotriton newts, have a biphasic lifestyle with aquatic and terrestrial environments imposing different constraints on limb skeleton. By employing the methods of computerized microtomography and 3D geometric morphometrics, we explored the pattern of morphological variation, disparity, modularity and morphological integration in the proximal parts of the anterior limbs of six species of Eurasian small bodied newts. Although the species significantly differ in limb shape, there is a great overlap in morphology of scapula and humerus, and there are no differences in morphological disparity. For the scapula, the shape differences related to the duration of the aquatic period are in length, depth and curvature. The shape of the humerus is not affected by the length of aquatic period, and shape differences between the species are related to robustness of the body. The length of aquatic period has statistically supported phylogenetic signal. The scapula and humerus are structures of varying modularity. For the humerus, the strongest support on the phylogenetic level was for the capitulum/shaft hypothesis, which can also be interpreted as functional modularity. For the scapula, the greatest support was for the antero‐posterior hypothesis of modularity in case of Lissotriton vulgaris, which can be explained by different functional roles and muscle insertion patterns, while there was no phylogenetic modularity. The modularity patterns seem to correspond with the general tetrapod pattern, with modularity being more pronounced in the distal structure. The future research should include more salamandrid taxa with different habitat preferences and both adult and larval stages, in order to explore how size, phylogeny and ecology affect the morphology and covariation patterns of limbs. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim Methods Results Conclusion Brexpiprazole is the first FDA‐approved treatment for agitation associated with dementia due to Alzheimer's disease. Agitation in Alzheimer's dementia (AAD) occurs in high prevalence and is a great burden for patients and caregivers. Efficacy, safety, and tolerability of brexpiprazole were demonstrated in the AAD clinical trials. To demonstrate the agitation‐ameliorating effect of brexpiprazole in animals, we evaluated brexpiprazole in two AAD mouse models.The resident–intruder test was conducted in 5‐ to 6‐month‐old Tg2576 mice, given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally 1 h before the test. Locomotor activity was measured in 6‐month‐old APPSL‐Tg mice given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally the evening before the start of locomotor measurement for 3 days.In the resident–intruder test, Tg2576 mice showed significantly higher attack number and shorter latency to first attack compared to non‐Tg mice. In the Tg mice, brexpiprazole treatment (0.03 mg/kg) significantly delayed the latency to first attack and showed a trend toward a decrease in attack number. APPSL‐Tg mice (≧6 months old) showed significantly higher locomotion during dark period Phase II (Zeitgeber time [ZT] 16–20) and Phase III (ZT20‐24) compared to non‐Tg mice, correlating with the clinical observations of late afternoon agitation in Alzheimer's disease. Brexpiprazole treatment (0.01 and 0.03 mg/kg) significantly decreased hyperlocomotion during the Phase III in APPSL‐Tg mice.The suppression of attack behavior and the reduction of nocturnal hyperlocomotion in these Tg mice may be indicative of the therapeutic effect of brexpiprazole on AAD, as demonstrated in the clinical trials. [ABSTRACT FROM AUTHOR]

Body mass plays a crucial role in determining the mass‐specific energy expenditure during terrestrial locomotion across diverse animal taxa, affecting locomotion patterns. The energy landscape concept offers a framework to explore the relationship between landscape characteristics and energy expenditure, enhancing our understanding of animal movement. Although the energy landscape approach solely considers the topographic obstacles faced by animals, its suitability compared to previous methods for constructing resistance maps and delineating corridors has not been comprehensively examined. In this study, we utilized the enerscape R package to generate resistance maps in kilocalories (kcal) by incorporating digital elevation models (DEMs) and body size data (kg). We assigned body sizes ranging from 0.5 to 100 kg to encompass a wide range of small and large mammals in Iran, adjusting maximum dispersal distances accordingly from 50 to 200 km. By analyzing these scenarios, we produced four resistance maps for each body size. Next, we identified potential corridors between terrestrial protected areas in Iran using the Linkage Mapper toolkit and examined barriers and pinch‐points along these paths. Our study revealed significant findings regarding the shared corridors between small and large mammals in Iran's landscape. Despite their differing body sizes and energy requirements, many corridors were found to be utilized by both small and large mammal species. For example, we identified 206 corridors for mammals weighing 500 g, which were also recognized as the least‐cost paths for 100 kg mammals. Thus, embracing a comprehensive method in resistance map creation, one that incorporates species‐specific traits and human infrastructure becomes imperative for accurately identifying least‐cost paths and consequently pinpointing pinch points and barriers. [ABSTRACT FROM AUTHOR]

Animals communicate acoustically to report location, identity, and emotive state to conspecifics. Acoustic signals can also function as displays to potential mates and as territorial advertisement. Music and song are terms often reserved only for humans and birds, but elements of both forms of acoustic display are also found in non‐human primates. While culture, bonding, and side‐effects all factor into the emergence of musicality, biophysical insights into what might be signaled by specific acoustic features are less well understood. Objectives: Here we probe the origins of musicality by evaluating the links between musical features (structural complexity, rhythm, interval, and tone) and a variety of potential ecological drivers of its evolution across primate species. Alongside other hypothesized causes (e.g. territoriality, sexual selection), we evaluated the hypothesis that perilous arboreal locomotion might favor musical calling in primates as a signal of capacities underlying spatio‐temporal precision in motor tasks. Materials and Methods: We used musical features found in spectrographs of vocalizations of 58 primate species and corresponding measures of locomotion, diet, ranging, and mating. Leveraging phylogenetic information helped us impute missing data and control for relatedness of species while selecting among candidate multivariate regression models. Results: Results indicated that rapid inter‐substrate arboreal locomotion is highly correlated with several metrics of music‐like signaling. Diet, alongside mate‐choice and range size, emerged as factors that also correlated with complex calling patterns. Discussion: These results support the hypothesis that musical calling may function as a signal, to neighbors or potential mates, of accuracy in landing on relatively narrow targets. [ABSTRACT FROM AUTHOR]

This study presents a modular, electronics‐free, and fully onboard control and actuation approach for shape memory alloy (SMA)‐based soft robots to achieve locomotion tasks. This approach exploits the nonlinear mechanics of compliant curved beams and carefully designed mechanical control circuits to create and synchronize rhythmic deformation cycles, mimicking the central pattern generators prevalent in animal locomotions. More specifically, the study elucidates a new strategy to amplify the actuation performance of the shape memory coil actuator by coupling it to a carefully designed, monostable curve beam with a snap‐through buckling behavior. Such SMA‐curved beam assembly is integrated with an entirely mechanical circuit featuring a slider mechanism. This circuit can automatically cut off and supply current to the SMA according to its deformation status, generating a self‐sustained rhythmic deformation cycle using a simple DC power supply. Finally, this study presents a new strategy to coordinate (synchronize) two rhythmic deformation cycles from two robotic modules to achieve efficient crawling locomotion but still use a single DC power. This work represents a significant step toward fully autonomous, electronics‐free SMA‐based locomotion robots with fully onboard actuation and control. [ABSTRACT FROM AUTHOR]

Metabolism underpins all life‐sustaining processes and varies profoundly with body size, temperature and locomotor activity. A current theory explains some of the size‐dependence of metabolic rate (its mass exponent, b) through changes in metabolic level (L). We propose two predictive advances that: (a) combine the above theory with the evolved avoidance of oxygen limitation in water‐breathers experiencing warming, and (b) quantify the overall magnitude of combined temperatures and degrees of locomotion on metabolic scaling across air‐ and water‐breathers. We use intraspecific metabolic scaling responses to temperature (523 regressions) and activity (281 regressions) in diverse ectothermic vertebrates (fish, reptiles and amphibians) to show that b decreases with temperature‐increased L in water‐breathers, supporting surface area‐related avoidance of oxygen limitation, whereas b increases with activity‐increased L in air‐breathers, following volume‐related influences. This new theoretical integration quantitatively incorporates different influences (warming, locomotion) and respiration modes (aquatic, terrestrial) on animal energetics. [ABSTRACT FROM AUTHOR]

Objectives: Although a bounding gait is practiced by a diversity of animals, the morphological characteristics, kinematics, and energetics associated with this locomotor form remain poorly understood. This study focuses on the locomotor anatomy of two species of African colobine monkeys (Piliocolobus badius, a leaper, and Colobus polykomos, a leaper–bounder) in an effort to assess if bounding should be considered a unique primate locomotor category or is better viewed as a behavior on a leaping continuum. Materials and Methods: A total of 53 femora, 28 humeri, and 45 ossa coxae from the two species provide comparative morphological data. Free‐body models of bounding and leaping are presented to characterize loading conditions. Species differences in morphometric traits are evaluated via parametric and nonparametric tests (i.e., analysis of variance, resampling). Results: C. polykomos exhibits traits that align more closely with putative leaping specializations when compared to P. badius (e.g., large femoral head, long femur, low femoral neck angle), while also possessing certain traits that are not (e.g., long femoral neck and reduced relative femoral robusticity). Consequently, C. polykomos likely experiences absolutely greater joint forces at the hip and higher bending at the femoral neck both when it leaps and bounds, given equivalent accelerations in bounding and leaping. Discussion: Bounding is best described as a form of low‐acceleration leaping. If bounding has lower acceleration requirements relative to leaping, C. polykomos achieves locomotor competence with less energy, relatively smaller bending moments, and reduced joint forces. [ABSTRACT FROM AUTHOR]

Objective: Exposure of neonatal macaques to the antiseizure medications phenobarbital and midazolam (PbM) causes widespread apoptotic death of neurons and oligodendrocytes. We studied behavior and neurocognitive performance in 12 to 24 month‐old macaques treated as neonates with PbM. Methods: A total of 14 monkeys received phenobarbital and midazolam over 24 hours under normothermia (n = 8) or mild hypothermia (n = 6). Controls (n = 8) received no treatment. Animals underwent testing in the human intruder paradigm at ages 12 and 18 months, and a 3‐step stimulus discrimination task at ages 12, 18, and 24 months. Results: Animals treated with PbM displayed lower scores for environmental exploration, and higher scores for locomotion and vocalizations compared with controls. Combined PbM and hypothermia resulted in lower scores for aggression and vigilance at 12 months compared with controls and normothermic PbM animals. A mixed‐effects generalized linear model was used to test for differences in neurocognitive performance between the control and PbM groups in the first step of the stimulus discrimination task battery (shape center baited to shape center non‐baited). The odds of passing this step differed by group (p = 0.044). At any given age, the odds of passing for a control animal were 9.53‐fold (95% CI 1.06–85) the odds for a PbM animal. There was also evidence suggesting a higher learning rate in the shape center non‐baited for the control relative to the PbM group (Cox model HR 2.13, 95% CI 1.02–4.43; p = 0.044). Interpretation: These findings demonstrate that a 24‐hour‐long neonatal treatment with a clinically relevant combination of antiseizure medications can have long‐lasting effects on behavior and cognition in nonhuman primates. ANN NEUROL 2024;95:57–70 [ABSTRACT FROM AUTHOR]

Amphibious robots, which are expected to move agilely in both land and water environments with huge differences in medium density, have always been a hot spot in the field of robotics. However, limited by the simple structure and drive system, the existing mini‐robots have a relatively single‐movement mode, which limits their ability to move in complex environments. This article fuses two different biomimetic morphological features to create an amphibious mini‐robot: mimicking the body shape and gait of a terrestrial inchworm, and mimicking the superhydrophobic leg shape and gait of an aquatic water strider. The light‐driven approach also brings the advantage of remote wireless manipulation. The mass of the robot is only 8 mg, and it has fast land movement speed (≈0.05 times body length s−1), water surface movement speed (≈0.5 times body length s−1), and some obstacle‐crossing ability (over obstacles of ≈64% of the robot's height). Moreover, the robot can quickly switch from land to water locomotion, which is expected to facilitate emerging applications in various industrial and biomedical settings. [ABSTRACT FROM AUTHOR]

To understand fitness consequences of performance, one must determine how underlying physiological traits result in and constrain performance. Biochemical and mechanistic investment in a performance trait may cause decreased performance elsewhere: a performance tradeoff, indicating performance specialization in a population. (Co)variation exists within individuals, and among individuals, populations, and species. Conflicting patterns of among‐individual and within‐individual covariation may eliminate, or mask, the relationship at the phenotypic level. Multivariate mixed‐effects models (MMMs) model within‐individual and among‐individual variation separately. We used MMMs to test for relationships between physiological and performance traits associated with locomotion in the prairie lizard Sceloporus consobrinus, and tested for tradeoffs at multiple hierarchical levels. We then compared these results to the conventional Pearson correlations. We found a significant among‐individual tradeoff between endurance and climbing speed. Positive covariation within individuals masked the tradeoff at the phenotypic level. Sprint speed positively covaried with climbing speed. Excluding anaerobic scope, which was associated with endurance, no measured physiological traits were predictive of locomotor performance. These data indicate that performance specialization exists among prairie lizards and contribute to a growing body of literature that have successfully used MMMs to uncover performance tradeoffs which may have been masked using conventional methods. [ABSTRACT FROM AUTHOR]

Intermittent locomotion is a common locomotor mode in small vertebrates. Pausing is thought to aid in locating a predator or prey, enhancing crypsis, lowering energy costs, and/or maneuvering around obstacles or toward a refuge. Many lizards flee predators by turning into potential refugia and subsequently pausing, presumably to conceal themselves. Intermittent locomotion may be associated with turning by allowing an animal time to assess its surroundings and/or decreasing the likelihood of losing its footing. In this study, we quantify locomotor performance and the use of intermittent locomotion in Florida scrub lizards (Sceloporus woodi) when navigating either a 45° or 90° turn. Lizards paused in 92.91% of all trials, and yet despite pausing, instantaneous speed was not different entering or exiting the turn. This result suggests that turning comes at minimal cost to forward speed for lizards under these conditions. Pausing during a turn, however, did slow speed in the turn. Interestingly, the speed in the turn did not differ in trials with a pause before the turn versus trials without a pause. The angle of the turn also had no effect on whether lizards paused. We found that lizards increase peak acceleration following pauses to compensate for lost speed during the pause, providing a mechanism that may minimize negative fitness effects associated with slow running speeds and allow intermittent locomotion to be such a common strategy in lizards. [ABSTRACT FROM AUTHOR]

Primate fingers are typically in direct contact with the environment during both locomotion and manipulation, and aspects of external phalangeal morphology are known to reflect differences in hand use. Since bone is a living tissue that can adapt in response to loading through life, the internal bone architecture of the manual phalanges should also reflect differences in manual behaviours. Here, we use the R package Morphomap to analyse high‐resolution microCT scans of hominid proximal phalanges of digits 2–5 to determine whether cortical bone structure reflects variation in manual behaviours between bipedal (Homo), knuckle‐walking (Gorilla, Pan) and suspensory (Pongo) taxa. We test the hypothesis that relative cortical bone distribution patterns and cross‐sectional geometric properties will differ both among extant great apes and across the four digits due to locomotor and postural differences. Results indicate that cortical bone structure reflects the varied hand postures employed by each taxon. The phalangeal cortices of Pongo are significantly thinner and have weaker cross‐sectional properties relative to the African apes, yet thick cortical bone under their flexor sheath ridges corresponds with predicted loading during flexed finger grips. Knuckle‐walking African apes have even thicker cortical bone under the flexor sheath ridges, as well as in the region proximal to the trochlea, but Pan also has thicker diaphyseal cortices than Gorilla. Humans display a distinct pattern of distodorsal thickening, as well as relatively thin cortices, which may reflect the lack of phalangeal curvature combined with frequent use of flexed fingered hand grips during manipulation. Within each taxon, digits 2–5 have a similar cortical distribution in Pongo, Gorilla and, unexpectedly, Homo, which suggest similar loading of all fingers during habitual locomotion or hand use. In Pan, however, cortical thickness differs between the fingers, potentially reflecting differential loading during knuckle‐walking. Inter‐ and intra‐generic variation in phalangeal cortical bone structure reflects differences in manual behaviours, offering a comparative framework for reconstructing hand use in fossil hominins. [ABSTRACT FROM AUTHOR]

Spinal motor neurons (SMNs) are the primary target of degeneration in amyotrophic lateral sclerosis (ALS). Degenerating motor neurons accumulate cytoplasmic TAR DNA‐binding protein 43 (TDP‐43) aggregates in most ALS cases. This SMN pathology can occur without mutation in the coding sequence of the TDP‐43‐encoding gene, TARDBP. Whether and how wild‐type TDP‐43 drives pathological changes in SMNs in vivo remains largely unexplored. In this study, we develop a two‐photon calcium imaging setup in which tactile‐evoked neural responses of motor neurons in the brainstem and spinal cord can be monitored using the calcium indicator GCaMP. We devise a piezo‐assisted tactile stimulator that reproducibly evokes a brainstem descending neuron upon tactile stimulation of the head. A direct comparison between caudal primary motor neurons (CaPs) with or without TDP‐43 overexpression in contiguous spinal segments demonstrates that CaPs overexpressing TDP‐43 display attenuated Ca2+ transients during fictive escape locomotion evoked by the tactile stimulation. These results show that excessive amounts of TDP‐43 protein reduce the neuronal excitability of SMNs and potentially contribute to asymptomatic pathological lesions of SMNs and movement disorders in patients with ALS. [ABSTRACT FROM AUTHOR]

Objectives: Morphological intraspecific variation is due to the balance between skeletal plasticity and genetic constraint on the skeleton. Osteogenic responses to external stimuli, such as locomotion, have been well documented interspecifically across the primate order, but less so at the intraspecific level. Here, we examine the differences in cross‐sectional variability of the femur, humerus, radius, and tibia in Pan troglodytes troglodytes versus Gorilla gorilla gorilla. We investigate whether there are sex, species, bone, and trait differences in response to variable body size and locomotion. Materials and Methods: Adult male and female P. t. troglodytes and G. g. gorilla long bones from the Cleveland Museum of Natural History were scanned with a peripheral quantitative computer tomography system. Scans were taken at the midshaft of each bone according to functional bone length. Coefficients of variation were used to provide a size‐independent measure of variation. We applied a Bonferroni correction to account for the multiple pairwise tests. Results: There were limited significant differences between males and females, however, females tended to be more variable than males. Variation in Gorilla, when significant, was greater than in Pan, although significant differences were limited. There were no differences between bone variability in male and female Gorilla, and female Pan. Discussion: Increased female variability may be due to more variable locomotor behavior, particularly during periods of pregnancy, lactation, and caring for an offspring compared to consistent locomotion over the life course by males. Body size may be a contributing factor to variability; more work is needed to understand this relationship. [ABSTRACT FROM AUTHOR]

Tree sloths evolved below‐branch locomotion making them one of few mammalian taxa beyond primates for which suspension is nearly obligatory. Suspension requires strong limb flexor muscles that provide both propulsion and braking/support, and available locomotor kinetics data indicate that these roles differ between fore‐ and hindlimb pairs. Muscle structure in the pelvic limb is hypothesized to be a key anatomical correlate of function in braking/support during suspensory walking and propulsion and/or support during vertical climbing. This expectation was tested by quantifying architecture properties in the hindlimb limb musculature of brown‐throated three‐toed sloths (Bradypus variegatus: N = 7) to distinguish the roles of the flexor/extensor functional muscle groups at each joint. Measurements of muscle moment arm (rm), mass, belly length, fascicle length, pennation angle, and physiological cross‐sectional area (PCSA) were taken from n = 45 muscles. Overall, most muscles studied show properties for contractile excursion and fast joint rotational velocity. However, the flexor musculature is more massive (p = 0.048) and has larger PCSA (p = 0.003) than the extensors, especially at the knee joint and digits where well‐developed and strong flexors are capable of applying large joint torque. Moreover, selected hip flexors/extensors and knee flexors have modified long rm that can amplify applied joint torque in muscles with otherwise long, parallel fascicles, and one muscle (m. iliopsoas) was capable of moderately high power in B. variegatus. The architectural properties observed in the hip flexors and extensors match well with roles in suspensory braking and vertical propulsion, respectively, whereas strong knee flexors and digital flexors appear to be the main muscles providing suspensory support in the pelvic limb. With aid in support by the forelimbs and the use of adaptive slow locomotion and slow muscle fiber recruitment patterns, structure–function in the tensile limb systems of sloths appears to collectively represent an additional mechanism for energy conservation. [ABSTRACT FROM AUTHOR]

Determining which traits allow species to live at higher elevations is essential to understanding the forces that shape montane biodiversity.For the many animals that rely on flight for locomotion, a long‐standing hypothesis is that species with relatively large wings should better persist in high‐elevation environments because wings that are large relative to the body generate more lift and decrease the aerobic costs of remaining aloft. Although these biomechanical and physiological predictions have received some support in birds, other flying taxa often possess smaller wings at high elevations or no wings at all.To test if predictions about the requirements for relative wing size at high elevations are generalizable beyond birds, we conducted macroecological analyses on the altitudinal characteristics of 302 Nearctic dragonfly species.Consistent with the biomechanical and aerobic hypotheses, species with relatively larger wings live at higher elevations and have wider elevation breadths—even after controlling for a species' body size, mean thermal conditions, and range size. Moreover, a species' relative wing size had nearly as large of an impact on its maximum elevation as being adapted to the cold.Relatively large wings may be essential to high‐elevation life in species that completely depend on flight for locomotion, like dragonflies or birds. With climate change forcing taxa to disperse upslope, our findings further suggest that relatively large wings could be a requirement for completely volant taxa to persist in montane habitats. [ABSTRACT FROM AUTHOR]

In nature, some semiaquatic arthropods evolve biomechanics for jumping on the water surface with the controlled burst of kinetic energy. Emulating these creatures, miniature jumping robots deployable on the water surface have been developed, but few of them achieve the controllability comparable to biological systems. The limited controllability and agility of miniature robots constrain their applications, especially in the biomedical field where dexterous and precise manipulation is required. Herein, an insect‐scale magnetoelastic robot with improved controllability is designed. The robot can adaptively regulate its energy output to generate controllable jumping motion by tuning magnetic and elastic strain energy. Dynamic and kinematic models are developed to predict the jumping trajectories of the robot. On‐demand actuation can thus be applied to precisely control the pose and motion of the robot during the flight phase. The robot is also capable of making adaptive amphibious locomotion and performing various tasks with integrated functional modules. [ABSTRACT FROM AUTHOR]

For living organisms, the ability to acquire information regarding the external space around them is critical for future actions. While the information must be stored in an allocentric frame to facilitate its use in various spatial contexts, each case of use requires the information to be represented in a particular self‐referenced frame. Previous studies have explored neural substrates responsible for the linkage between self‐referenced and allocentric spatial representations based on findings in rodents. However, the behaviors of rodents are different from those of primates in several aspects; for example, rodents mainly explore their environments through locomotion, while primates use eye movements. In this review, we discuss the brain mechanisms responsible for the linkage in nonhuman primates. Based on recent physiological studies, we propose that two types of neural substrates link the first‐person perspective with allocentric coding. The first is the view‐center background signal, which represents an image of the background surrounding the current position of fixation on the retina. This perceptual signal is transmitted from the ventral visual pathway to the hippocampus (HPC) via the perirhinal cortex and parahippocampal cortex. Because images that share the same objective‐position in the environment tend to appear similar when seen from different self‐positions, the view‐center background signals are easily associated with one another in the formation of allocentric position coding and storage. The second type of neural substrate is the HPC neurons' dynamic activity that translates the stored location memory to the first‐person perspective depending on the current spatial context. [ABSTRACT FROM AUTHOR]

Pangolin species are notoriously difficult to detect and monitor in the wild and, as a result, commonly used survey techniques fall short in gathering sufficient data to draw confident conclusions on pangolin populations, conservation status, and natural history. The white‐bellied pangolin is a semiarboreal species that may be poorly detected in general mammal surveys even with modern techniques such as camera‐trapping. As a result, population status information is often derived from hunting, market, and trafficking data. There is therefore a crucial need to improve camera‐trap survey methods to reliably detect this species in its natural environment. Here, we test the influence of camera‐trap placement strategy on the detectability of the white‐bellied pangolin by comparing estimates from targeted ground‐viewing camera‐trapping and a novel log‐viewing placement strategy adapted from local hunters' knowledge. Our results suggest that (1) deploying camera‐traps to detect animals walking along logs is an effective strategy for recording several forest species, including the white‐bellied pangolin, and (2) that camera‐traps targeting logs are more efficient at detecting white‐bellied pangolins than camera‐traps viewing the ground (>100% increase in detection probability). We also found moderate evidence that there is a relationship between the white‐bellied pangolin occurrence at our locality and elevation and weak evidence of an association with distance to the nearest river. Our results suggest an effective new monitoring approach allowing consistent detection of the white‐bellied pangolin with moderate survey effort. This highlights the importance of harnessing local knowledge to guide the design of monitoring protocols for cryptic species. [ABSTRACT FROM AUTHOR]

Objectives: When studying hominin skeletal remains, anthropologists commonly assume that the morphology of entheses (muscle and tendon attachment sites) is influenced by physical activity patterns during life. Here, we use samples of mice from a prior experiment (Siegel & Jones [1975] American Journal of Physical Anthropology 42:141–144) to test this assumption. Specifically, we investigate the effects of habitual climbing on entheses of the humerus using a recently developed protocol for analyzing entheseal morphology called the "Validated Entheses‐based Reconstruction of Activity" (VERA) method. Materials and Methods: In the original experiment, young mice were raised for approximately 9 weeks in one of two experimental conditions: a cage designed to limit locomotion to terrestrial quadrupedalism over a flat surface (n = 22), or a cage designed to impel animals to cling to a suspended wire mesh apparatus and limit their locomotion to climbing (n = 21). We μCT‐scanned the humeri of these mice and used the VERA method to assess the morphology of the deltoid tuberosity, greater tubercle, lesser tubercle, and supinator crest. Results: Significant differences in entheseal morphology were detected between climbers and non‐climbers when using both multivariate statistics to assess all entheses simultaneously and univariate statistics to assess each enthesis individually. Discussion: Our results provide new support for the general use of entheseal morphology for inferring hominin physical activity patterns in the past. Furthermore, based on our results, we propose that analyzing entheseal morphology using the VERA method may be a promising strategy for future research on the importance of climbing in hominin locomotor evolution. [ABSTRACT FROM AUTHOR]

Aim: This study aims to address the role of the interaction between subthalamic (STN) neurons and substantia nigra pars compacta (SNc) dopaminergic (DA) neurons in movement control. Methods: Fiber photometry and optogenetic/chemogenetic techniques were utilized to monitor and manipulate neuronal activity, respectively. Locomotion in mice was recorded in an open field arena and on a head‐fixed apparatus. A hemiparkinsonian mouse model was established by unilateral injection of 6‐OHDA in the medial forebrain bundle. Whole‐cell patch‐clamp techniques were applied to record electrophysiological signals in STN neurons and SNc DA neurons. c‐Fos‐immunostaining was used to label activated neurons. A rabies virus‐based retrograde tracing system was used to visualize STN neurons projecting to SNc DA neurons. Results: The activity of STN neurons was enhanced upon locomotion in an open field arena and on a head‐fixed apparatus, and the enhancement was significantly attenuated in parkinsonian mice. Optogenetic stimulation of STN neurons enhanced locomotion, increased activity of SNc DA neurons, meanwhile, reduced latency to movement initiation. Combining optogenetics with patch‐clamp recordings, we confirmed that STN neurons innervated SNc DA neurons through glutamatergic monosynaptic connections. Moreover, STN neurons projecting to SNc DA neurons were evenly distributed in the STN. Either 6‐OHDA‐lesion or chemogenetic inhibition of SNc DA neurons attenuated the enhancement of locomotion by STN stimulation. Conclusion: SNc DA neurons not only affect the response of STN neurons to movement, but also contribute to the enhancement of movement by STN stimulation. This study demonstrates the role of STN‐SNc interaction in movement control. [ABSTRACT FROM AUTHOR]

The Smithsonian Institution's National Museum of American History houses the largest remaining collection of inter‐positive composite glass plate images from the production of Eadweard Muybridge's Animal Locomotion series. These photographs, which are approximately 150 years old, exhibit a wide range of degradation phenomena and products, including alteration of the glass plates. Compositions of both the image‐bearing glass plates and support glass panels were obtained through quantitative scanning electron microscope–energy‐dispersive spectrometry. Electron imaging of cross‐sectioned samples of the image‐bearing glass plates reveals a visible sodium‐depleted glass alteration layer. Furthermore, electron imaging shows delamination of the image‐containing gelatin layer and captures evidence that suggests that interfacial stresses between the glass alteration layer and the unaltered glass contribute to the delamination of this layer along with the overlaid gelatin. [ABSTRACT FROM AUTHOR]

The anatomy of the sternum in birds varies according to their habitats and type of locomotion. In particular, the carina sterni manifest different shape variations. In this study, the shape of the carina sterni was investigated by means of geometric morphometrics. Birds of different types of locomotion were used in the study: flying, swimming, and terrestrial. Ducks and chickens show a wider variety of shapes. Pigeons are the species with the least differences. The margo cranialis carinae in a turkey is the flattest compared to other species. In chickens, the apex carinae is more caudally than the base of the carina sterni. The margo cranialis of the carina sterni in ducks is concave. The differences in centroid size and shape differences between species collectively are statistically significant (p < 0.0001). The most distinct shape contrast is between the duck and turkey (p: 0.0003). Form differences between the ducks and geese as well as between the chicken and turkey are statistically insignificant. There is less variation in the shape of the carina sterni among avian species representing the same type of locomotion. Although there are many comparative morphological and morphometric studies of birds, shape analysis studies revealing the interspecific differences and similarities of the sternum are very limited. Morphology of the carina sterni can be useful in taxonomic investigations. [ABSTRACT FROM AUTHOR]

In this study, we present not only a new and detailed anatomical description of the epaxial muscles and adjacent ligamentous and fascial structures in the African savanna elephant but also a structural and functional comparison with other Afrotherian mammals and some domestic quadrupeds. All structures were examined by means of standard anatomical techniques. The back of the largest land mammal is a crucial part of trunk construction according to the bow and string concept, which is applied also in other quadrupedal animals. The epaxial muscles of the African savanna elephant play an important role in the biomechanical properties of the entire back and in supporting and moving the heavy head. Situated in the short cervical region of the African savanna elephant is a large mass comprised of numerous muscle individuals together with a well‐developed ligamentum nuchae. Parts of the mm. interansversarii ventralis cervicis form a strong muscle belly, which was named the m. intertransversarius longus. Whereas the head is held in a high or extended position most of the time during locomotion, the head and neck are highly mobile while the animal is foraging or socially interacting. Movements between the elements of the thoracic and lumbar spine are likely to be very limited due to the obvious rigidity of the bony vertebral column. Aponeuroses surrounding long epaxial muscles could contribute to an energy‐saving mechanism, which is active during both stance and locomotion. The well‐developed m. serratus dorsalis cranialis helps in facilitating effective breathing in an animal, which is equipped with an unusual pleural structure. [ABSTRACT FROM AUTHOR]

Background: The robust brown capuchin monkey (Sapajus apella) is a South American primate with preferences for arboreal locomotion, which requires specific thoracic limb muscle adaptations. The present investigation studied the gross anatomy of the extrinsic and intrinsic scapular and brachial muscles. Methods: Gross dissections were performed in both thoracic limbs of four formaldehyde‐fixed specimens. Results: Three rhomboideus muscles were present (capitis, cervicis, and thoracis). The trapezius muscle was divided into two parts (cervicis and thoracis). The pectoralis abdominalis and omotransversarius muscles were present. The anconeus muscle was found as an individual muscle or fused to the caput mediale of the triceps brachii muscle. The brachialis muscle had among one and two heads. The anconeus epitrochlearis was absent. Conclusion: These muscles of Sapajus apella are adapted for arboreal locomotion and some terrestrial habits, since these have many similarities with other primates with a similar locomotor patterns. [ABSTRACT FROM AUTHOR]

The dynamics of fish assemblages in reservoirs depend on factors such as the morphometry of the catchment, habitat structure, and the uses of the reservoir. In the Paraíba do Sul (PSR) basin in southeastern Brazil, there are several types of reservoirs, some on the main channel, some are cascade reservoirs originated from a diversion of the waters of the PSR, and others are isolated reservoirs from tributaries. This study aimed to evaluate the influences of these three types of reservoirs on the taxonomic and functional distinctness of the fish assemblages. It was hypothesized that reservoirs on the main channel (more inflowing waters and habitat availability) have higher taxonomic and functional distinctness compared to cascade reservoirs, which in turn, have greater distinctness than isolated reservoirs. In addition, we expect assemblage structure to differ among these types of reservoirs because of the close relationship with local environmental conditions and habitat structure. Thirty measurements (26 quantitative and 4 categorical) from 34 fish species representing functional traits associated with locomotion, feeding, life strategy, and habitat use were taken. Fish assemblages differed among the three types of reservoirs, which was probably associated with different environmental and local habitat conditions. Higher taxonomic and functional distinctness were found for the isolated reservoirs, and lower for reservoirs on the main channel. This suggests that the fish fauna in this latter type of reservoir were probably composed of phylogenetically close and morphologically similar species. It is likely that limitation of the available resources induces fish to partition the available niches to coexist, favoring assemblages with species adapted to different functions. Our results demonstrate that assessing fish functional and taxonomic distinctness can be used to advance understanding of fish communities from reservoirs in Neotropical regions. [ABSTRACT FROM AUTHOR]

During dynamic locomotion, animals employ tails to help control the orientation of their bodies. This type of control is pervasive throughout locomotion strategies. Roboticists endeavor to close the gap between robots and their biological counterparts by developing various active tails. This work explores these active tails and establishes a design strategy to enhance reorientation performances. A dynamic model to describe the transmitted torques at the body from the single‐axis active tail is suggested. The design parameters, which define the transmitted torques, are analyzed through the dynamic model to understand their contributions. The effects of aerodynamics on the active tail's performance are also explored. The active tails are categorized according to inertial tail designs (unbalanced distal mass or mass‐balanced about a rotating point), aerodynamic configurations (inertial, aerodynamic, aerodynamic with external airflow), and operating strategies (partial oscillation, symmetric oscillation, asymmetric‐oscillation or full rotations). The reorientation performance of 24 possible active tail combinations is explored and design strategies to select the proper combinations according to the target system's conditions are provided. This work can help in guiding the advanced active tail designs for future agile mobile robots. [ABSTRACT FROM AUTHOR]

Muscle spindles, one of the two main classes of proprioceptors together with Golgi tendon organs, are sensory structures that keep the central nervous system updated about the position and movement of body parts. Although they were discovered more than 150 years ago, their function during movement is not yet fully understood. Here, we summarize the morphology and known functions of muscle spindles, with a particular focus on locomotion. Although certain properties such as the sensitivity to dynamic and static muscle stretch are long known, recent advances in molecular biology have allowed the characterization of the molecular mechanisms for signal transduction in muscle spindles. Building upon classic literature showing that a lack of sensory feedback is deleterious to locomotion, we bring to the discussion more recent findings that support a pivotal role of muscle spindles in maintaining murine and human locomotor robustness, defined as the ability to cope with perturbations. Yet, more research is needed to expand the existing mechanistic understanding of how muscle spindles contribute to the production of robust, functional locomotion in real world settings. Future investigations should focus on combining different animal models to identify, in health and disease, those peripheral, spinal and brain proprioceptive structures involved in the fine tuning of motor control when locomotion happens in challenging conditions. [ABSTRACT FROM AUTHOR]

The cerebellum is involved in encoding balance, posture, speed, and gravity during locomotion. However, most studies are carried out on flat surfaces, and little is known about cerebellar activity during free ambulation on slopes. Here, it has been imaged the neuronal activity of cerebellar molecular interneurons (MLIs) and Purkinje cells (PCs) using a miniaturized microscope while a mouse is walking on a slope. It has been found that the neuronal activity of vermal MLIs specifically enhanced during uphill and downhill locomotion. In addition, a subset of MLIs is activated during entire uphill or downhill positions on the slope and is modulated by the slope inclines. In contrast, PCs showed counter‐balanced neuronal activity to MLIs, which reduced activity at the ramp peak. So, PCs may represent the ramp environment at the population level. In addition, chemogenetic inactivation of lobule V of the vermis impaired uphill locomotion. These results revealed a novel micro‐circuit in the vermal cerebellum that regulates ambulatory behavior in 3D terrains. [ABSTRACT FROM AUTHOR]

Total dissolved gas (TDG) supersaturation from sources such as hydroelectric dams can cause harmful bubble growth in the tissues of aquatic animals, known as gas bubble trauma (GBT). Locomotion is known to exacerbate bubble growth in tissues during decompression under certain conditions (such as in diving animals), possibly because of increased bubble nucleation. As with decompression sickness, GBT is caused by the supersaturation of tissues with gas, and thus we hypothesize that locomotion promotes bubble nucleation in the tissues of fish exposed to TDG supersaturation. Many previous laboratory studies have tested the effects of TDG on fish exposed to low‐velocity, non‐directional flow, whereas fish in field conditions are exposed to higher‐velocity flows and are likely more active. Therefore, it is important to understand the effects of locomotion on GBT to apply laboratory results to active fish in field conditions. We exposed rainbow trout (Oncorhynchus mykiss) to either control (100% TDG) or TDG supersaturation (123% TDG) in either static or flowing water conditions (1.8 Bl/s) and recorded time to 50% loss of equilibrium (LOE). We observed no statistically significant difference in time to 50% LOE between flow conditions. Given the lack of statistically significant difference between static and flowing water, our findings indicate that results from GBT experiments on rainbow trout in non‐directional flow are applicable to more active individuals. [ABSTRACT FROM AUTHOR]

Miniaturized untethered soft robots are recently exploited to imitate multi‐modal curvilinear locomotion of living creatures that perceive change of surrounding environments. Herein, the use of Caenorhabditis elegans (C. elegans) is proposed as a microscale model capable of curvilinear locomotion with mechanosensing, controlled by magnetically reconfigured 3D microtopography. Static entropic microbarriers prevent C. elegans from randomly swimming with the omega turns and provide linear translational locomotion with velocity of ≈0.14 BL s−1. This velocity varies from ≈0.09 (for circumventing movement) to ≈0.46 (for climbing) BL s−1, depending on magnetic bending and twisting actuation coupled with assembly of microbarriers. Furthermore, different types of neuronal mutants prevent C. elegans from implementing certain locomotion modes, indicating the potential for investigating the correlation between neurons and mechanosensing functions. This strategy promotes a platform for the contactless manipulation of miniaturized biobots and initiates interdisciplinary research for investigating sensory neurons and human diseases. [ABSTRACT FROM AUTHOR]

Robust locomotion relies on information from proprioceptors: sensory organs that communicate the position of body parts to the spinal cord and brain. Proprioceptive circuits in the spinal cord are known to coarsely regulate locomotion in the presence of perturbations. Yet, the regulatory importance of the brain in maintaining robust locomotion remains less clear. Here, through mouse genetic studies and in vivo electrophysiology, we examined the role of the brain in integrating proprioceptive information during perturbed locomotion. The systemic removal of proprioceptors left the mice in a constantly perturbed state, similar to that observed during mechanically perturbed locomotion in wild‐type mice and characterised by longer and less accurate synergistic activation patterns. By contrast, after surgically interrupting the ascending proprioceptive projection to the brain through the dorsal column of the spinal cord, wild‐type mice showed normal walking behaviour, yet lost the ability to respond to external perturbations. Our findings provide direct evidence of a pivotal role for ascending proprioceptive information in achieving robust, safe locomotion. Key points: Whether brain integration of proprioceptive feedback is crucial for coping with perturbed locomotion is not clear.We showed a crucial role of the brain for responding to external perturbations and ensure robust locomotion.We used mouse genetics to remove proprioceptors and a spinal lesion model to interrupt the flow of proprioceptive information to the brain through the dorsal column in wild‐type animals.Using a custom‐built treadmill, we administered sudden and random mechanical perturbations to mice during walking.External perturbations affected locomotion in wild‐type mice similar to the absence of proprioceptors in genetically modified mice.Proprioceptive feedback from muscle spindles and Golgi tendon organs contributed to locomotor robustness.Wild‐type mice lost the ability to respond to external perturbations after interruption of the ascending proprioceptive projection to the brainstem. [ABSTRACT FROM AUTHOR]

Bite force represents a critical measure of an animal's feeding capabilities and has been analyzed in the context of ecology and body size in numerous vertebrate lineages. Among birds, bite force potential has been comprehensively quantified in finches; however, no in vivo data have been reported within parrots (order: Psittaciformes), and an anatomical estimate of bite force has been calculated for only two species. Despite this paucity of data, the parrot feeding system represents one of the most functionally interesting among tetrapods, exhibiting many anatomical novelties unique among birds and contributing to locomotion when parrots climb vertical surfaces. Within this study, we present in vivo bite force data from six rosy‐faced lovebirds (Agapornis roseicollis) at a range of gapes (2.5–10 mm, or 20–50°). These data are contextualized against more than 70 other avian taxa for which bite forces have been previously reported. Our findings demonstrate that bite forces decreased iteratively with each increase in gape size, with all between‐group differences yielding statistical significance. Relative to other birds, Agapornis, Psittacus, and Myiopsitta all exhibit larger bite forces than would be expected for their body size. We infer that the diet of parrots – many of which are specialized granivores, capable of crushing large and mechanically resistant seeds – may have contributed to their relatively strong biting capabilities. This interpretation is supported by other recent studies highlighting how the mechanical properties of foods drive bite forces in other vertebrate lineages, such as lizards and bats. [ABSTRACT FROM AUTHOR]

Aim: Understanding and predicting the biological consequences of climate change requires considering the thermal sensitivity of organisms relative to environmental temperatures. One common approach involves 'thermal safety margins' (TSMs), which are generally estimated as the temperature differential between the highest temperature an organism can tolerate (critical thermal maximum, CTmax) and the mean or maximum environmental temperature it experiences. Yet, organisms face thermal stress and performance loss at body temperatures below their CTmax, and the steepness of that loss increases with the asymmetry of the thermal performance curve (TPC). Location: Global. Time period: 2015–2019. Major taxa studied: Ants, fish, insects, lizards and phytoplankton. Methods: We examine variability in TPC asymmetry and the implications for thermal stress for 384 populations from 289 species across taxa and for metrics including ant and lizard locomotion, fish growth, and insect and phytoplankton fitness. Results: We find that the thermal optimum (Topt, beyond which performance declines) is more labile than CTmax, inducing interspecific variation in asymmetry. Importantly, the degree of TPC asymmetry increases with Topt. Thus, even though populations with higher Topts in a hot environment might experience above‐optimal body temperatures less often than do populations with lower Topts, they nonetheless experience steeper declines in performance at high body temperatures. Estimates of the annual cumulative decline in performance for temperatures above Topt suggest that TPC asymmetry alters the onset, rate and severity of performance decrement at high body temperatures. Main conclusions: Species with the same TSMs can experience different thermal risk due to differences in TPC asymmetry. Metrics that incorporate additional aspects of TPC shape better capture the thermal risk of climate change than do TSMs. [ABSTRACT FROM AUTHOR]

Background: The clinical examination of lame horses in real world settings often requires the use of sloped surfaces. Objectives: This pilot study aimed to evaluate the effects of uphill and downhill locomotion on asymmetry in horses with naturally occurring lameness affecting forelimbs and hindlimbs. Methods: Ten horses (8–19 years) with forelimb lameness and eight horses (7–16 years) with hindlimb lameness were fitted with inertial sensors at the poll, withers, sacrum and both tuber coxae. Data were collected whilst the horses were trotted in hand on a level surface (<0.7%), as well as up and down a minor slope of 2.4%. Data were collected for a minimum of 25 strides at each incline type. Effect of incline was compared using a repeated measures ANOVA and, where significant, a subsequent Bonferroni's multiple comparisons. Results: Of the horses with hindlimb lameness, there were reductions in asymmetry seen during downhill locomotion when compared with trotting on the flat (flat: 6.6 ± 4.4 mm to downhill: 1.9 ± 2.9 mm; p = 0.015) and when compared with uphill locomotion (8.4 ± 4.3 mm; p = 0.007). Horses with forelimb lameness showed no significant difference in asymmetry. However, there were considerable changes in poll asymmetry (>20 mm) among conditions in individual horses. Two horses with hindlimb lameness and two horses with forelimb lameness switched asymmetry between left and right by changing incline. Conclusions: These results confirm that incline can be an influential factor in the assessment of lame horses. Further work is justified to elucidate the types of pathology associated with the most relevant changes in asymmetry which would allow the use of an incline to prioritise a list of differential diagnoses. [ABSTRACT FROM AUTHOR]

Amphibious robots can undertake various tasks in terrestrial and aquatic environments for their superior environmental compatibility. However, the existing amphibious robots usually utilize multi‐locomotion systems with transmission mechanisms, leading to complex and bulky structures. Here, a miniature amphibious robot based on vibration‐driven locomotion mechanism is developed. The robot has two unique rigid‐flexible hybrid modules (RFH‐modules), in which a soft foot and a flexible fin are arranged on a rigid leg to conduct vibrations from an eccentric motor to the environment. Then, it can run on ground with the soft foot adopting the friction locomotion mechanism and swim on water with the flexible fin utilizing the vibration‐induced flow mechanism. The robot is untethered with a compact size of 75 × 95 × 21 mm3 and a small weight of 35 g owing to no transmission mechanism or joints. It realizes the maximum speed of 815 mm s–1 on ground and 171 mm s–1 on water. The robot, actuated by the RFH‐modules based on vibration‐driven locomotion mechanism, exhibits the merits of miniature structure and fast movements, indicating its great potential for applications in narrow amphibious environments. [ABSTRACT FROM AUTHOR]

Designs perfected through evolution have informed bioinspired animal‐like robots that mimic the locomotion of cheetahs and the compliance of jellyfish; biohybrid robots go a step further by incorporating living materials directly into engineered systems. Bioinspiration and biohybridization have led to new, exciting research, but humans have relied on biotic materials—non‐living materials derived from living organisms—since their early ancestors wore animal hides as clothing and used bones for tools. In this work, an inanimate spider is repurposed as a ready‐to‐use actuator requiring only a single facile fabrication step, initiating the area of "necrobotics" in which biotic materials are used as robotic components. The unique walking mechanism of spiders—relying on hydraulic pressure rather than antagonistic muscle pairs to extend their legs—results in a necrobotic gripper that naturally resides in its closed state and can be opened by applying pressure. The necrobotic gripper is capable of grasping objects with irregular geometries and up to 130% of its own mass. Furthermore, the gripper can serve as a handheld device and innately camouflages in outdoor environments. Necrobotics can be further extended to incorporate biotic materials derived from other creatures with similar hydraulic mechanisms for locomotion and articulation. [ABSTRACT FROM AUTHOR]

Joint range of motion (RoM) analyses are fundamental to our understanding of how an animal moves throughout its ecosystem. Recent technological advances allow for more detailed quantification of this RoM (e.g. including interaction of degrees of freedom) both in ex vivo joints and in vivo experiments. Both types of data have been used to draw comparisons with fossils to reconstruct locomotion. Salamanders are often used as analogues for early tetrapod locomotion; testing such hypotheses requires an in‐depth analysis of salamander joint RoM. Here, we provide a detailed dataset of the ex vivo ligamentous rotational joint RoM in the hindlimb of the fire salamander Salamandra salamandra, using a new method for collecting and visualising joint RoM. We also characterise in vivo joint RoM used during walking, via scientific rotoscoping and compare the in vivo and ex vivo data. In summary, we provide (1) a new method for joint RoM data experiments and (2) a detailed analysis of both in vivo and ex vivo data of salamander hindlimbs, which can be used for comparative studies. [ABSTRACT FROM AUTHOR]

Sex‐specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth‐brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex‐specific functional performance trade‐offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth‐brooding. This study explored sexual dimorphism and morphological trait adaptations related to feeding, breeding, respiration and locomotion performance in two paternal mouth‐brooding freshwater fishes (Glossamia aprion and Neoarius graeffei). Eight morphological traits were evaluated for sexual dimorphism (non‐brooder males vs. females) and male breeding state differences (brooders vs. non‐brooders). Male breeding state was a significant predictor of trait variation in both species. Brooders differed in buccal volume and in several feeding and locomotory traits compared to non‐brooder males. Non‐brooder males had bigger buccal volumes and relative eye diameters (G. aprion) and larger relative gape sizes (N. graeffei) compared to females, a potential response to both mouth‐brooding and feeding requirements. Although there were clear trait differences between brooder and non‐brooder males, further research is required to confirm whether individuals return to their former morphology once mouth‐brooding has ceased or if trait differences are maintained post‐brooding. This study highlights the importance of considering the potential impacts of intraspecific trait variation on the performance of critical life functions, such as feeding, respiration and locomotion across the life history. [ABSTRACT FROM AUTHOR]

Comparative study of terrestrial locomotion of 4 fish genera including Anabas, Channa, Clarias, and Monopterus, was performed in experimental setting with the substrate surface of wet clay. No special adaptations for terrestrial locomotion were found. Every fish uses for propulsion on land what it already has. Eel‐shaped Monopterus crawls by body undulations in a serpentine or sidewinding technique, the latter of which was not previously observed beyond snakes. The other 3 fish genera walk by body oscillations using stiff appendages as propulsors. When they are located anteriorly, as the serrate operculum in Anabas and the preaxial spine of the pectoral fin in Clarias, the propulsion is termed prolocomotor, when posteriorly, as the spiny anal fin in Channa—metalocomotor. Channa is the heaviest fish walking out of water in our days, quite comparable in size with first Devonian tetrapods Acanthostega and Tulerpeton. A theoretical calculation is suggested for the upper size limit of a fish capable of terrestrial walking without special locomotor adaptations. It should be roughly 20 cm in the vertical dimension of the trunk, which is just a little above the known size of Devonian tetrapodomorph fishes Panderichthys and Elpistostege. The metalocomotor walking technique of Channa is suggested as the closest extant model for terrestrial locomotion at the fish‐tetrapod transition. The major difference is that the metalocomotor propulsor in Channa is represented by the anal fin, while in tetrapodomorphs by the pelvic fins. The sprawled pelvic fins were advantageous in respect of reduced requirement for side‐to‐side tail swinging. [ABSTRACT FROM AUTHOR]