Integrative and Comparative Biology最新文献

The tongue plays a crucial role in feeding by positioning, manipulating, and transporting the bolus during chewing and swallowing. As a muscular hydrostat, its biomechanical function relies on regional deformations and coordinated movements with the jaw. Sensory feedback from oral afferents, particularly via the trigeminal nerve, is critical for modulating these movements and deformations. This study investigates how food texture and oral sensory perturbations influence tongue kinematics in an omnivorous carnivoran, the skunk (Mephitis mephitis). Using X-ray Reconstruction of Moving Morphology (XROMM) and controlled nerve blocks to the tongue and teeth, we analyzed tongue protraction-retraction, regional lengthening-shortening, and their timing relative to the gape cycle across three foods-banana, carrot, and kibble. Results indicate that food properties significantly impact tongue movements, with soft foods like banana eliciting greater anteroposterior motion and posterior tongue deformation. Despite these kinematic differences, the timing of tongue movements relative to jaw cycles remains consistent, but there are differences in the timing of regional lengthening and shortening between foods. Bilateral nerve blocks altered tongue kinematics and deformations, particularly regional deformations, but did not disrupt overall coordination with the chewing cycle. These findings suggest that oral afferents refine motor commands, optimizing tongue-bolus interactions while rhythmic jaw-tongue coordination patterns are maintained. This study enhances our understanding of sensorimotor integration in mammalian feeding and provides insights on tongue biomechanics as a muscular hydrostat.

Atlanta, renowned for its extensive urban tree canopies, embodies the concept of a "city in a forest." Spelman College, a historically Black college (HBCU), despite its relatively small footprint, acts as a steward for a small but vital portion of this urban forest. This compact campus, a shared habitat for students and a diverse ecosystem of trees, offers a unique living timeline of the institution's history. However, significant opportunities remain untapped in leveraging this environment for research and deeper student engagement with nature. This article describes the unique opportunities and rationale for student-staff collaborations within the Spelman Arboretum, highlighting how such partnerships can bridge the gap between urban students and their natural surroundings, expand scientific understanding beyond traditional disciplines, and foster a stronger sense of community. It presents several examples of activities born from the Tree Map project, a faculty learning community initiative-demonstrating the range of potential collaborations-and planning future projects from them. Furthermore, it invites faculty across disciplines to conduct studies within the Spelman Arboretum, bringing their science into the public eye and transforming the campus into a dynamic urban laboratory. By showcasing the Spelman Arboretum project as a potential model, we aim to inspire a comprehensive approach that utilizes this unique campus environment to ask interesting research questions and unify the college community.

Wildlife populations increasingly encounter unpredictable environmental conditions and reduced resource availability, influencing energy and protein available for immune defenses. According to resource-constraint hypotheses, central to ecoimmunology, organisms with more resources should have the ability to invest more into immune defenses. We investigated whether fat condition or protein content influenced three constitutive immune defenses-bacterial killing ability, hemolytic complement activity, and total antioxidant capacity-in mule deer (Odocoileus hemionus). We used hundreds of samples from individuals captured during 2014-2021 and generalized linear models fit in a Bayesian framework to determine the probability of the direction of a relationship. Bacteria-killing ability had greatest probability (0.87) of a positive relationship with fat condition, and a 0.84 probability of a negative relationship with protein. In contrast, hemolytic complement activity had a 0.93 probability of being negatively associated with protein content and antioxidant capacity had a 0.94 probability of a positive association with protein content. Neither had a clear directional relationship with fat condition. Still, absolute effect sizes were small, and immune differences between a deer in poor nutritional condition and one in good nutritional condition were minor. The small effect sizes were contrary to the assumptions of many studies and might arise because the immune defenses in this study were constitutive, highly regulated by negative feedback cycles, and had low energy and resource costs. These nuanced results, however, support different, albeit small, effects of protein and fat reserves on immune defenses. Our results highlight the importance of assessing the assumed relationship between immune defenses and nutritional reserves in each population.

Existing and emerging diseases threaten wildlife populations worldwide and population resilience in the face of disease depends on immune responses. To apply conservation strategies to populations threatened by disease, it is critical to know not only how individuals will respond to the initial exposure of the pathogen but also to determine risks when the pathogen becomes endemic or is reintroduced. Immune responses following a subsequent exposure to a pathogen may vary from initial responses due to several immunological memory mechanisms such as adaptive immune function and innate immune priming/training and tolerance. Alternatively, immune responses may vary as a consequence of resource limitation. Regardless of outcome, these altered responses could impact how individuals respond to successive pathogen exposures in their environment. Disease threatens reptiles worldwide but research on reptilian immunology has lagged behind other taxonomic groups, resulting in large gaps in our understanding of both mechanistic and functional immune responses. Reptiles possess traditionally considered "innate" and "adaptive" immune components, but current literature seems to agree that reptiles depend largely on innate immune components as adaptive responses are slow. We present an exploratory study in which we measured functional immune responses in male red-eared slider turtles (Trachemys scripta elegans) to 2 antigen injections representing bacterial (lipopolysaccharide), viral (polyinosinic-polycytidylic acid; poly(I:C), fungal infections (zymosan), and control (saline), administered 2 weeks apart. We separated serum and buffy layer (serum + BL) from blood samples and manipulated the serum + BL (fresh, frozen, frozen + heat) to systematically inactivate immune components. We conducted microbial killing assays using the manipulated serum + BL with Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, and the diploid yeast Candida albicans, which allowed us to examine immune responses across various contexts. Although sample sizes were small, we observed varied responses across treatments and serum + BL/microbe assay combinations, suggesting that several mechanisms of immune memory may have occurred after the first treatment injection. Given the time frame of our exploratory study and previous research on acquired antibody production timing in reptiles, we suggest that our observations may be products of immune training/priming, tolerance, and resource reallocation. However, more work is necessary to examine these processes in reptiles and we make suggestions for future research directions. Our work further demonstrates the role that diverse immunological tools have in understanding immune strategies across taxa to enhance our knowledge of reptilian immunology and inform conservation decisions.

The mammalian tongue is a muscular hydrostat composed of multiple muscles, each with complex fiber architecture and small motor units. This allows it to move and deform in three dimensions (3D) to function in several complex behaviors, including suckling. The ability of infant mammals to successfully suckle is dependent on these variable deformations, as the tongue must perform multiple functions simultaneously. The lateral margins of the tongue curl to seal around a nipple, while the middle of the tongue moves in an anteroposterior wave to suck milk into the mouth, transport it posteriorly, and swallow it. The kinematics, mechanics, and coordination of the tongue during suckling are impacted by nipple properties, as evidenced by differences between feeding from nipples with narrow ducts (e.g., breastfeeding) and nipples that are hollow cisterns (e.g., bottle feeding). These structural differences result in different feeding outcomes, yet their effect on tongue function and kinematics is poorly understood. In addition, despite the 3D shape of the tongue during suckling, measurements of tongue movement have been limited to motion along the midsagittal plane and have not assessed suck volume. To evaluate how tongue function differs between ducted and cisternic nipples, we used X-ray Reconstruction of Moving Morphology and a dynamic endocast, synchronized with intraoral suction, to quantify 3D tongue kinematics and suck volume. We found that pigs generated less suction but had greater suck volumes when they fed on cisternic nipples compared to ducted nipples. This is likely because the pigs compressed the cisternic nipple to express milk, resulting in higher flow, which we hypothesize slowed the accumulation of suction and permitted the tongue to achieve a larger suck volume. These results suggest that nipple design impacts the relationship between fluid dynamics and tongue function during feeding. In addition, we found that infants moved the surface of their tongue ventrally and posteriorly throughout the suck, but they did not increase the width of the suck volume. The use of a digital endocast to measure suck volume represents an important advance in our ability to evaluate the mechanics of feeding and could be used in the future to understand the relationships between tongue function and performance as infants mature, as well as in a comparative framework.

Understanding wildlife immune responses is crucial for assessing disease risks, environmental stress effects, and conservation challenges. Traditional ecoimmunology approaches rely on targeted assays, which, while informative, often provide a fragmented and species-limited view of immune function. Proteomics offers a powerful alternative by enabling the high-throughput, system-wide quantification of immune-related proteins, providing a functional perspective on immunity that overcomes many limitations of conventional methods. However, proteomics remains underutilized in ecoimmunology despite its potential to enhance biomarker discovery, host-pathogen interaction studies, and environmental health assessments. This perspective highlights proteomics as a transformative tool for ecoimmunology, disease ecology, and conservation biology. We discuss its unique advantages over other -omics approaches, including its ability to capture realized immune function rather than inferred gene expression, its applicability to diverse wildlife taxa, and its potential for longitudinal immune monitoring of individuals using minimally invasive sampling. We also address key challenges, including limited genomic reference resources, sample constraints, reproducibility issues, and the need for standardized protocols. To overcome these barriers, we propose practical solutions, such as leveraging proteomes of closely related species for annotation and using their annotated genomes as search spaces for peptide mapping. Additionally, we highlight the importance of alternative quality control strategies and improved data-sharing practices to enhance the utility of proteomics in wildlife research. To fully integrate proteomics into ecoimmunology, we recommend expanding public reference databases for non-model species, refining field-adapted workflows, and fostering interdisciplinary collaboration between ecologists, immunologists, and bioinformaticians. By embracing these advancements, the field can leverage proteomics to bridge the gap between molecular mechanisms and ecological processes, ultimately improving our ability to monitor wildlife health, predict disease risks, and inform conservation strategies in the face of environmental change.

Many animal structures and appendages are pressurized, cylindrical, and helically wrapped with fibers. Squid tentacles, elephant trunks, echinoderm tube feet, notochords, arteries, and the bodies of sharks, nematodes, and annelids are all helically wrapped and their structural function depends on force transmission by this wrapping. Classical understanding of helically-wrapped cylinders in biology originates with calculations and concepts developed in the context of worm bodies, particularly nemerteans, turbellarians, and nematodes. This work recognized the geometric effects of the fiber angle on the cylinder volume and the fiber stretch. Subsequent work on tongues, tentacles, trunks, and polychaete worms used cylinder geometry to infer mechanical advantage. However, these studies did not explicitly consider forces and hence are limited in developing a general understanding for the mechanics of soft skeletons. Recently, a more precise theory was developed that incorporates force transmission, enhancing an understanding of mechanical and displacement advantage in these biological hydrostats. Some general insights are derivable from this foundation. A pressurized cylinder has a hoop stress that is twice the longitudinal stress and a crossed-helical wrapping of fibers can carry all of those stresses, if the fibers are at the magic angle of 54.7°. In a variable-volume cylinder with inextensible fibers, the magic angle corresponds to the maximum enclosed volume, but in a constant-volume cylinder, shape change necessitates stretching of the helical fibers. Strain and the length-to-radius ratio (aspect ratio) are functions of fiber angle, but aspect ratio also depends on the number of fiber wrappings. A constant-volume cylinder at any other angle will generate higher pressure, stretch helical fibers, store energy, cause shape changes, and possibly generate axial or radial external forces. Due to geometry, the mechanical advantage of force transmission from longitudinal muscles to radial output forces is not the inverse of the mechanical advantage of circumferential muscles transmitting force to the axial direction. Additionally, the mechanical advantage of short, wide cylinders is higher in extension than that of longer, thinner cylinders, suggesting that short and wide earthworm and polychaete segments have a higher mechanical advantage in generating axial forces during burrowing. Helical fibers can reduce the mechanical advantage during extension and retraction because energy is stored in the fibers; stiffer fibers reduce the mechanical advantage more; and some worms have helical muscles that might allow behavioral modulation of mechanical advantage. These inferences demonstrate insights that may be gleaned from explicit considerations of the mechanical principles of hydrostatic skeletons.

Hydrostatic skeletal support is widespread among animals. If modeled as an isovolumetric cylinder that is longer than it is wide, a hydrostatic structure should undergo large changes in length for relatively small changes in diameter. This presents an underappreciated consequence for the muscle fibers controlling hydrostatic skeletal shape: longitudinally oriented muscle fibers may experience remarkably long operating ranges. Superelongation, or the ability to produce relatively high forces over an extreme range of muscle lengths, may thus be necessary for longitudinally oriented fibers. We discovered superelongation and an interesting morphological specialization in an obliquely striated muscle of the polychaete worm Glycera dibranchiata. These worms have an eversible proboscis that is used for burrowing and prey capture. The proboscis retractor muscles extend from the body wall to the gut and likely undergo a large stretch during proboscis eversion. Like two other previously described superelongating muscles in squid and leeches, the proboscis retractor muscles had a broad length-force relationship (LFR). At a given muscle length, however, some muscle fibers were folded while others were not (i.e., the folded fibers were longer than the whole muscle, at least when the muscle was partially contracted). The number of folded fibers and extent of folding were higher at shorter muscle lengths. We hypothesize that the short muscle fibers experience tension at all muscle lengths, while the folded fibers only experience tension at long whole muscle lengths. Thus, each retractor muscle contains populations of fibers of different lengths that may contribute differentially to the broad LFR. Superelongation with varying fiber folding may represent a previously unrecognized strategy in obliquely striated muscle for permitting high force production over a broad range of muscle lengths needed for hydrostatic skeletal support.

Artificial flowers have long been used in pollinator research to understand and manipulate key floral features such as rewards and display. Increased access to 3D printing and Internet of Things (IoT) technologies has expanded the capabilities of artificial flowers, enabling more precise control and real-time data collection. These IoT-enabled artificial flowers, referred to as robotic flowers or robo-flowers, integrate single-board computers, such as the Raspberry Pi series or similar embedded system devices, as well as affordable camera and sensor modules. However, despite their flexibility and modularity, the majority of robotic flowers are designed to investigate how pollinators make foraging decisions based on visual cues linked to floral rewards, with less attention paid to the broader information landscape that pollinators use to decide which flowers to visit. We have developed a robotic flower system that extends this approach to incorporate multimodal signaling capabilities as well as aversive floral stimuli. These stimuli were designed to allow for investigation into the more nuanced information tradeoffs that feature in pollinators foraging decisions, but the designs could be broadly useful for researchers interested in understanding insect nociception, decision-making, and apparent predation in the context of plant-pollinator interactions.

When terrestrial organisms locomote in natural settings, they must navigate complex surfaces that vary in incline angles and substrate roughness. Variable surface structures are common in arboreal environments and can be challenging to traverse. This study examines the walking gait of katydids (Tettigoniidae) as they traverse a custom-built platform with varying incline angles ($30^circ$, $45^circ$, $60^circ$, $75^circ$, $90^circ$) and substrate roughness (40, 120, and 320 grit sandpaper). Our results show that katydids walk more slowly as the incline angle increases and as katydid mass increases, with a decrease of around 0.3 body lengths per second for every 1$^circ$ increase in incline. At steeper inclines and larger sizes, katydids are also less likely to use an alternating tripod gait, opting instead to maintain more limbs in contact with the substrate during walking. Katydids also increased average duty factor when climbing steeper inclines and with increasing body mass. However, substrate roughness did not affect walking speed or gait preference in our trials. These findings provide insights into how environmental factors influence locomotor strategies in katydids and enhance our understanding of effective locomotor strategies in hexapods.