Integrative and Comparative Biology最新文献

The tongue, as a muscular hydrostat, performs several dynamic behaviors and functions, including feeding, vocalizing, and respiration. As such, this hydrostat must be capable of performing complex movements, which are powered via a set of muscles typically defined as "extrinsic" (originating outside of the tongue) and "intrinsic" (contained wholly in the tongue). These muscles are typically classified based on their gross anatomical positions and also are often ascribed functions based on these positions, with the extrinsic muscles being assigned the role of positioning the tongue, and the intrinsic muscles thought to function to shape it. For example, genioglossus is typically described as a tongue protruder, whereas hyoglossus is often described as a tongue retractor. However, the neural control of these muscles involves relatively small motor units, and defining the function of tongue muscles based on anatomy, when they occupy overlapping space and exhibit refined control may oversimplify their function. Yet, distinguishing between gross anatomical structures and refined neural control can be challenging due to the complexity of functions the tongue performs. Here, we used an infant animal model (pigs) to evaluate how the neural control of the tongue is modulated in anatomical space given a relatively simplified behavior (suckling). We tested for variation in control along the anteroposterior and dorsoventral axis of the tongue using high speed videofluoroscopy coupled with electromyography (EMG). We found variation in EMG firing timing along both axes, which correspond to differences in behaviors. Furthermore, this variation in activity is likely reflected by regional variation in function within a muscle. These data suggest that defining muscles by their anatomical structure over-simplifies their functional roles and that studies investigating the three-dimensional structure and function of the tongue should evaluate it based on regional variation in control, in the context of the behavior of interest.

The scientific enterprise of the United States is facing challenges on a scale that many living scientists have never encountered. After nearly a century of bipartisan support, the prominence of American science is threatened by dramatic cuts to the federal budget, political interference, and special interests. Although portions of the American public may be generally aware of these challenges, many are not well-versed in what the forthcoming changes mean for future advances in knowledge, our health, the environment, and the economy. Most training in science has focused on communicating the technical details of our methodology and findings to other scientists. Disparate training opportunities and few incentives for outward-facing communication have made many scientists poorly trained to combat the increasingly loud, well-funded, and hostile anti-science movement. In this Editorial, I highlight the differences in how scientists communicate with one another compared to how other professional communicators reach their established audiences and continue to grow those audiences. By describing 5 high-order strategies of effective communication, I aim to lower the barriers for fellow scientists to experiment with new communication opportunities that will reach wider audiences. At a time when anti-science propaganda is running rampant, scientists and their professional organizations should dedicate increased effort toward communicating with new audiences at local, regional, and national levels.

Nature is an unparalleled innovator, coming up with countless solutions over millions of years. From the microscopic structures of gecko feet that enable effortless climbing to the hydrodynamic efficiency of fish armor, biological systems have evolved to solve a myriad of complex challenges. Engineers have long drawn inspiration from these natural innovations, translating biological principles into new technologies. The process is rarely straightforward-biological structures evolve under constraints and trade-offs, often leading to multifunctional designs that do not conform to traditional engineering approaches. Here, we explore the dynamic exchange between biology and engineering, highlighting how bioinspired design not only informs new technologies but also deepens our understanding of living systems. Bioinspired design plays a crucial role in materials science, robotics, and biomedical sciences, underscoring the need for interdisciplinary collaboration. Existing partnerships between biologists and engineers have led to advances in adhesives, protective materials, filtration systems, and dynamic structural designs. Translating biological complexity into engineered simplicity can be challenging; we need open communication between fields to share methodologies, resources, and discoveries. By fostering a continuous feedback loop between biology and engineering, we can push the boundaries of innovation and discovery, ensuring that bioinspired design remains a driving force in scientific and technological advancement.

Wildlife health comparisons within and across populations and species are essential for population assessment and surveillance of emerging infectious diseases. Due to low costs and high informational yield, hematology is commonly used in the fields of ecoimmunology and disease ecology, yet consistency and proper reporting of methods within these fields are lacking. Previous investigations on various wildlife taxa have revealed noteworthy impacts of the vein used for blood collection on hematology measures. However, the impacts of venipuncture site on bats, a taxon of increasing interest in ecoimmunology and disease ecology, have not yet been tested. Here, we use a long-term study system in western Oklahoma to test the effect of venipuncture site on hematology parameters of the Mexican free-tailed bat (Tadarida brasiliensis) and cave myotis (Myotis velifer), two abundant and representative bat species from the families Molossidae and Vespertilionidae. Between September 2023 and October 2024, we collected paired peripheral blood from both the propatagial and intrafemoral veins in 25 individuals per species. We then quantified total red and white blood cells, reticulocyte counts, and leukocyte differentials and used generalized linear mixed models to compare parameters among venipuncture sites within and between bat species. Overall, venipuncture site had no effect on any hematology parameters; however, we revealed small differences in neutrophil and lymphocyte proportions between veins among the species. By contrast, we detected significant species-level differences in most cell measurements, which we propose could be explained by life-history strategy and phylogenetic differences. We encourage continued testing of additional venipuncture sites, and of the same venipuncture sites on different species, on hematology and other health metrics used in ecoimmunology and disease ecology. Lastly, we emphasize the importance of thorough method reporting in publications to enable transparent comparisons and accounting for even small sampling-based artifacts. All future efforts are especially important for bats to improve conservation monitoring, ecosystem services estimations, and their association with emerging infectious diseases.

Biological segmented armors integrate mineralized tiles with soft tissues, forming a structure that is both puncture resistant and flexible. In the 9-banded armadillo Dasypus novemcinctus, scapular and pelvic buckler osteoderm tiles are hexagonally shaped, tapering from the superficial face down to the deep face. Each osteoderm is embedded in the dermis and adjacent osteoderms are connected to one another via connective Sharpey's fibers. Our study hierarchically investigated the relationship between armor geometry, connective fibers, and soft supporting layers during flexion. We used micro-CT scans to inform the design of simplified 3D-printed buckler osteoderm models with 3 taper angles, 2 types of connective layers of different compliances (elastic and rigid), and one soft silicone rubber layer. Resistance to bending for 18 model combinations were tested using a 3-point bend test. We found that tapered tiles form a "sweet spot" between flexibility and rigidity. Tapered geometry decreased the stiffness of the system, while models without tapers greatly increased the stiffness via increased tile interactions. The stiff fabric set a limit for bending, regardless of taper type, and there was no additive effect when combining stiff and elastic fabrics. The silicone rubber increased the flexural stiffness of the model and helped to redistribute forces. This study further demonstrates that armadillo armor is complex and relies on hard-soft interfaces to resist bending and to translocate damaging forces. When creating bio-inspired models, it is imperative to take biological complexity into account, yet test the system hierarchically to better predict the role of the geometry as well as the material (hard and soft elements).

The inherent benefits of soft materials in robotic designs have rendered soft robotics a growing field in research and engineering. Due to their compliance, soft robots are safe in working environments shared with humans, offer great potential in health care and medical applications, and may be operational in environments inaccessible or unfit for their solid body counterparts. However, for truly soft, self-contained robots, onboard electronics-free control is required. While there are pneumatic transistors that can be combined to simple control logics, the weight of these circuits may sometimes overburden soft-legged robots. To overcome the weight limitation of our current soft robotic prototypes, we sought inspiration from nature by studying the leg morphology and parasagittal gait of mammals. They have been shaped by evolution to support the heaviest terrestrial animals on earth: elephants. We assume that the leg morphology and strides of elephants are optimized for energy efficiency and/or load bearing, and we translated their characteristics to a pneumatically actuated elephant soft robotic leg. However, as soft actuators are remarkably different from the mammal joint-and-muscle system, a direct transfer from joint angles and muscle movement is not desirable. We therefore adapted the known kinematics of elephant strides to PneuNet bending actuators by means of approximating the actuators' bending angles to elephants' joint angles and subsequently arranging different actuator states into a sequence in order to approximate the elephant strides. We here present our current version of a biomimetic soft walker with parasagittal gait achieving a speed of 126 mm/s (0.82 body lengths per second) and a total load capacity of >5.2 × its body weight.

During swallowing, a diverse range of mammals-from opossums to humans-propel food boluses out of the oropharynx via tongue base retraction (TBR). The widespread distribution of TBR behavior implies an ancient evolutionary origin, but the biomechanical mechanisms of TBR remain poorly understood. The evolution of TBR behavior is further complicated by the diversity of hyoid and tongue anatomy across mammals: to what extent does hyolingual morphology shape TBR mechanism? Using biplanar videoradiography and the XROMM workflow, we collected high-resolution 3D kinematic data in opossums (Marsupialia), dogs (Placentalia), and macaques (Placentalia) to test hypotheses on the evolutionary conservation of TBR mechanisms. Despite differences in hyolingual morphology and resting hyoid position, both dogs and macaques drive TBR through hyoid movement: hyoid excursions reduce the oral volume and squeeze the tongue base posteriorly, analogous to a hydraulic pump displacing an incompressible fluid. In opossums, however, intrinsic lingual muscles deform the tongue base to initiate TBR, independent of hyoid movement and oral volume change. We suggest that multiple mechanisms are viable for the highly conserved TBR behavior across mammals, and the functional diversity of TBR mechanisms is decoupled from the morphological diversity of the hyolingual system. This decoupling may have facilitated the evolution of novel hyolingual phenotypes while avoiding trade-offs in swallowing performance.

Bio-inspired design has become a significant driver of innovation, enabling the development of effective solutions to some of the world's toughest challenges. Bio-inspired design leverages evolutionary advancements to create products and processes that are often more efficient and sustainable. However, applying biological insights to engineering can be challenging due to the distinct ways the two disciplines define and interpret core concepts. This paper explores the cognitive and technical skills required to effectively translate biological inspiration into engineering solutions. Our hypothesis focuses on bridging the "language and representation gap" between biology and engineering. The goal of this paper is to identify key aspects of biological representation that enable its successful adaptation into engineering design, fostering the development of more impactful and efficient bio-inspired solutions. The analysis of student feedback and ideation outputs revealed that engineers preferred biology texts with a medium level of technical complexity, balancing ease of understanding with image quantity. Basic references were found to support diverse idea generation, while more technical texts proved useful and necessary for understanding in-depth biological insights and applying them to engineering problems. Future research could explore the impact of information presentation order, the role of biological experts in deepening insights, and the use of machine learning to refine how biological information is selected and categorized to enhance the bio-inspired design process.

Amphibians, like other vertebrates, respond to stressors through the activation of the hypothalamic-pituitary-interrenal (HPI) axis, leading to elevated levels of glucocorticoids in the bloodstream. The amphibian HPI axis is functionally analogous to the mammalian hypothalamic-pituitary-adrenal (HPA) axis, coordinating the stress response via glucocorticoid release. Among these, corticosterone (CORT) acts as the principal downstream effector hormone, exerting widespread effects on various physiological systems. As seen in many other vertebrates, physiologically increased CORT levels are commonly associated with immune modulation, which might enhance or suppress the immune response. This immune outcome is influenced by several factors, including the duration and intensity of the stressors, the body condition of individuals, life history, and species-specific traits. Here, we provide a literature review on the role of stressors and CORT in amphibian immunity, including studies conducted in natural environments and controlled settings. These studies involve standardized stress protocols (i.e., restraint, captivity, and exogenous hormone treatment), along with "in vivo" and "in vitro" immune assays. Overall, CORT levels and their effects on immunity are highly variable, yet they do not act in isolation. There is significant interaction between CORT and other hormones, such as testosterone and melatonin, which further influences the immune response in amphibians. This interplay underscores the complexity of the stress-immune relationship and suggests that a holistic approach is essential to fully understand the impact of stressors on amphibian health and conservation.

We present a portable, noninvasive, and low-cost three-dimensional tracking method to quantify in situ water-hopping kinematics of mudskippers. By combining dual-camera video recordings with tracking the fish path, Gaussian Splatting terrain reconstruction and stereo matching, we capture detailed 3D trajectories of mudskippers in their natural tidal-flat habitats. Our proposed method resolves hopping motions including both straight and curved escape paths, and reveals that horizontal stride length, hopping height, and velocity are strongly influenced by fish length and local terrain features. These results highlight both the biomechanical and ecological significance of water-hopping in mudskippers, demonstrating how a simple, deployable 3D approach can resolve complex amphibious movements in challenging field environments.