Integrative and Comparative Biology最新文献

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.

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.

Reptiles are increasingly faced with conservation challenges and ecoimmunological techniques would be a beneficial tool in monitoring and evaluating populations that are at-risk. However, the reptilian immune system is poorly understood, and few studies have made intraspecies comparisons, making generalizations difficult. To help address this gap, innate immune function across three conspecific freshwater turtle species was evaluated. Red-eared sliders (Trachemys scripta elegans), Mississippi mud (Kinosternon subrubrum hippocrepis), and musk turtles (Sternotherus odoratus), are found throughout the Southeastern USA and represent different ecological microhabitats and life histories. In spring 2024, male aquatic turtles were caught using hoop nets, and blood samples were taken to assess immune characteristics. Microbial killing assays were conducted using multiple blood serum and buffy layer (hereafter referred as "serum + BL") manipulations (fresh, frozen, and frozen + heat manipulated serum + BL) as well as three microbes that activate specific immunological responses: Gram-positive bacterium (Staphylococcus aureus), Gram-negative bacterium (Escherichia coli), and a fungus (Candida albicans). By using this suite of microbial assays, differences in immune prioritization can be observed across species. This study revealed that there are differences in immunocompetence in each species of freshwater turtle that varied by microbe and serum + BL manipulation. We determined that because of the contribution of complement proteins when challenged against Gram-negative bacteria, frozen manipulated serum + BL appears to be a reliable way to assess immunocompetence in individuals across turtle species. Conducting intraspecies comparisons in immune function using integrative approaches can provide valuable insight into the underlying patterns of physiological variability within wild organisms, especially those that are of conservation concern.

Dermal denticles (scales) are important in influencing the movement of water around a shark's body. To date, most of the research on denticle morphology and their impacts on hydrodynamics has focused on the lateral flank of fast-swimming species. One understudied region where these interactions may be important is the nares of sharks. The constant flow of water through the nares is critical to olfaction and therefore a shark's survival. We imaged dermal denticles all around the incurrent and excurrent nares of the Pacific spiny dogfish (Squalus suckleyi), a benthopelagic species inhabiting eastern Pacific waters. At the incurrent naris, we quantified denticle morphological traits such as length, width, aspect ratio, ridge number, and angle of rotation off the anterior-posterior axis. We found that denticles at the incurrent naris display two primary morphologies: elongated with ridged crowns and rounded with smooth crowns. Moreover, we show denticles rotated to nearly 180 degrees off the anterior-posterior axis as denticles enter the incurrent naris at the cranial region. Using particle image velocimetry over a 3D printed model of a micro-computed tomography scan of the incurrent naris, we visualized the effects of this rotation on flow and found preliminary data for a reverse circulating vortex in addition to laminar flow into the olfactory chamber. Finally, we propose two hypotheses on the importance of this phenomenon. This work highlights the diversity of shark denticle morphology, particularly with respect to their role in fluid mechanics. Our findings challenge our current understanding of dermal denticle orientation and function, further supporting the need to investigate areas of interest across shark bodies that have not yet been studied in the literature.

Vertebral deformities such as abnormal curvatures and shapes may influence kinematics of fishes during swimming. Our study examines the vertebral deformities of hatchery-reared lumpfish (Cyclopterus lumpus) to better understand the effects of vertebral deformity on swimming kinematics. We recorded and analyzed videos of 50 juvenile lumpfish that were being raised as cleaner fish for salmonid farms. Each lumpfish was observed in 10-s video intervals and then euthanized for X-ray visualization of the skeleton. We used midline tracking to calculate speed, tailbeat amplitude, stride length, tailbeat frequency, and tail curvature during volitional swimming. Body shape analysis using 2D landmarking and principal component analysis showed that there was a significant relationship between the number of deformities and body shape from a dorsal view. We also found that body shape from a lateral view was a significant predictor of speed and stride length. We expected that an increase in deformity would cause a change in tail curvature and a decrease in speed, stride length, tailbeat frequency, and tail amplitude. Instead, we found that the lumpfish swimming was mostly unaffected by the deformity. There was only a significant relationship between tailbeat amplitude and number of early compressed vertebrae. Since vertebral deformities had a significant relationship with body shape, there was also an indirect effect of deformity on swimming speed.

Increasingly sophisticated taxonomic tools have enhanced our understanding of species diversity and phylogenetic relationships in elasmobranchs. Nevertheless, ichthyologists continue to face challenges in resolving the taxonomic placement and authentication of some taxa, particularly those originally described based on morphology. The recently described genus Fontitrygon comprises several Atlantic dasyatid stingrays whose phylogenetic positions have remained unresolved due to the lack of molecular data. In this study, we employed an integrative taxonomic approach to identify and determine the phylogenetic position of the understudied Fontitrygon garouaensis from Nigeria. Specimens were collected from freshwater ecosystems along the Jebba and Lokoja stretches of the River Niger in Nigeria. Comparative morphological analysis distinguished F. garouaensis from other Fontitrygon species by the presence of a depressed central-spine shaft with flanges extending along either side, a flattened oval disc, an obtuse snout, a whip-like tail bearing a sting, a broad and elongated snout, small pelvic fins, and radially arranged pectoral fins. Additionally, morphological measurements of the newly collected F. garouaensis were consistent with those of the syntype and holotype, confirming species identification. Phylogenetic analyses based on mitochondrial cytochrome c oxidase subunit I gene sequences recovered Fontitrygon as a monophyletic lineage and identified F. garouaensis as the sister taxon to F. margarita and F. margaritella. This study provides an integrative taxonomic assessment of F. garouaensis, clarifying its species identity and confirming the presence of F. garouaensis from the upstream of the Jebba stretch of the River Niger. We, therefore, propose an update to its IUCN geographic range.

Wildlife face a number of extrinsic stressors, such as habitat loss, pathogen infections, and contaminant exposure, which can increase the energy needed to maintain optimal health and survival. These multiple extrinsic stressors can also occur simultaneously during intrinsically stressful life stages such as reproduction, migration, or hibernation. To fully understand how to support healthy wildlife populations, we must quantify physiological and immunological phenotypes across a variety of stressors. We pose a framework for conducting field studies to collect individual-level samples that can be used for measuring physiological and immunological phenotypes as well as the potentially stressful intrinsic and extrinsic drivers of those phenotypes. We suggest that collaborative efforts should then be made to create broader, spatially coordinated hypotheses for determining patterns of wildlife health under intrinsically stressful time periods and across extrinsically stressful landscapes. We provide an example and preliminary findings for this multi-stressor, collaborative, and spatially coordinated approach with an ongoing study of North American bat health. Quantifying direct and critical measures of wildlife health and identifying key intrinsic and extrinsic stressors that drive physiological and immunological phenotypes will provide broad targets for conservation strategies and where and when those strategies should be prioritized in the future.

The increasing emergence of virulent pathogens necessitates novel approaches to predict and manage infectious disease risks. The importance of integrating observational and experimental approaches to studying host-pathogen interactions has long been recognized, as captive studies can mechanistically test hypotheses derived from field studies and identify causal factors shaping host susceptibility or tolerance of infection. However, captive experiments can also determine biomarkers of infection outcomes that could improve later interpretation of field data and identify at-risk hosts in wild populations. Such work could be especially useful in preempting or managing risks of pathogen spillover or spillback. SARS-CoV-2 emerged in humans in late 2019 and was rapidly followed by spillback into naïve wildlife, leading to both mortality events and novel enzootic cycles. Of special concern is whether SARS-CoV-2 could establish in bats in the Americas, given that sarbecoviruses coevolved with rhinolophid bats in the Eastern Hemisphere, and as coronavirus infection may exacerbate effects of white-nose syndrome. Here, we leverage residual plasma samples from a previous SARS-CoV-2 challenge study of Mexican free-tailed bats (Tadarida brasiliensis) to identify candidate protein biomarkers of susceptibility and test whether these can predict coronavirus risks in wild bats. We generated plasma proteomes from captive (n = 20; four resistant, five susceptible, 11 unchallenged) and wild (n = 15) bats using the S-Trap method and LC-MS/MS, identifying 475 proteins using data-independent acquisition and a species-specific genome annotation generated by the Bat1K Project. Receiver operator characteristic curves identified 27 potential biomarkers of SARS-CoV-2 susceptibility (AUC ≥ 0.8), and subsequent enrichment analyses of these proteins suggested downregulation of blood clotting and upregulation of complement activation and humoral immunity in susceptible bats. We then mined plasma proteomes from wild bats (sampled in 2022 from Bracken Cave Preserve, the largest known Mexican free-tailed bat population) to show that all candidate biomarkers were present in this population, with coefficients of variation ranging from 16 to 150% per protein. We detected coronaviruses in 20% of wild bats, with two cases of potential SARS-CoV-2 spillback. We demonstrate that at least four of these candidate susceptibility biomarkers classified bats with and without coronavirus infection in the wild. Our results inform the possible immune strategies underlying SARS-CoV-2 susceptibility in bats and give a preliminary example of how captive challenge studies can be coupled with field studies to inform zoonotic and conservation risks.

Comparative biomechanics describes investigating animal models to inform, understand, and improve health and locomotor understanding in humans and across biological organisms and species. In recent years, there has been an increased understanding of comparative biomaterials, which utilizes intincredibly diverse, yet can primarilyerdisciplinary techniques spanning physics, materials science, engineering, and biology to mimic and model the complex morphology and mechanics of biological structures. This perspective piece highlights some recent innovations in biological material characterization of mechanics, morphology, and composition, highlighting specific innovations that help address classical challenges in biomaterials analysis. It concludes with a review of highlights in material fabrication techniques that have expanded the scope of biomaterials through bio-inspired multi-material 3-dimensional printing, textiles, and bio-hybrids. This perspective serves as a starting guide for researchers to broaden their understanding of the innovations that different disciplines have made in characterizing biological materials across various length scales, which could be applied to bio-inspired design.