Integrative and Comparative Biology最新文献

Integration and modularity can have a profound impact on the function and evolution of environmentally responsive traits, especially when they result in discrete, alternative forms-that is, developmental polyphenism. An unresolved issue for understanding this impact is the degree to which the genetic architectures of the individual components of a plastic trait permit independent versus coordinated evolution. The association of trait variation with genomic variation can provide a test of whether the same loci influence different components of the same integrated phenotype. An example of a coordinated, plastic trait is in the shark-tooth nematode Pristionchus pacificus, which develops into either a bacterial-feeding or a predatory adult morph, depending on its perception of local food availability. Moreover, this polyphenism, when measured as morph induction in response to a common set of cues, differs across natural isolates of the species. By creating recombinant inbred lines (RILs) from natural isolates that have diverged in their morph-induction bias, followed by quantitative trait locus analysis, we tested whether and the extent to which component traits of this resource polyphenism are linked. We found that RILs with more frequent induction of the predatory morph also produced Eu individuals that were more effective predators. We also found that these two traits are associated with the same major-effect locus, suggesting that their causal genes are physically linked, if not the same, and are therefore likely to experience coordinated selection. In contrast, we found that morphological variation was not linked to these two traits and that such variation within each morph was even independent of variation in the other. Our findings show that the same coordinated plastic trait exhibits a blend of genetic correlation and independence, whose balance shapes the trait's evolutionary potential.

Understanding how plant innovations arise and persist requires connecting mechanisms across biological scales. The growing accessibility of genomic data and methodological advances in phylogenetic comparative methods provide unprecedented opportunities to achieve this integration. Yet, functional tools remain unevenly distributed across the plant Tree of Life, and conceptual differences across scales of inquiry limit integration. Here, we highlight emerging approaches that bridge developmental, genomic, and macroevolutionary research to generate a more comprehensive view of plant evolution. We propose building a "Functional Tree of Plant Life" by investing in shared infrastructure and funding programs for developing transformation techniques and building genetic resources to incentivize research in non-model taxa. Concurrently, further methodological advances in phylogenetic comparative methods are needed to continue accommodating complex developmental, genomic, and transcriptomic data. Combined, these efforts would enable experimental validation of gene function across diverse lineages and improve reconstructions of the evolution of genetic pathways and the developmental origins of key phenotypes. Building this integrative framework will require both conceptual synthesis, collaboration, and community investment but offers a transformative path toward understanding the evolution of plant form and function.

Over the course of development, sensory systems must integrate specialized cells and tissues to generate a functional unit. A robust example of this type of integration is the lateral line, a mechanosensory system in fishes and amphibians that senses changes in water movement. Over the past century, numerous reports noted that the principal organs of the lateral line-neuromasts-co-localize to the position of ossification centers for bones of the facial skeleton. More recent work in the freshwater model system, Astyanax mexicanus, revealed facial bones of the suborbital complex frequently fuse in a manner consistent with approximated neuromasts. In cave dwelling morphs, which lack a structural eye, positioning of the neuromasts encircling the orbit differ from closely related, eyed surface-dwelling morphs. This suggests facial bone fusion patterns are a function of eye regression, which interferes with neuromast positioning early in development. Here, we compared adult bone fusion patterns from individuals derived from three cavefish populations derived from at least two independent cave colonizations-the Pachón, Tinaja and Molino caves. Interestingly, despite established asymmetries impacting the cavefish craniofacial complex, no asymmetric bias was observed in facial bone fusion. Surface fish showed minimal fusion, however cave morphs showed substantial facial bone fusion which varied in severity by cave population. Facial bone fusion is therefore not a simple function of eye regression, since each eyeless cavefish population harbored different patterns of fusion severity. We propose intra-population variation in bone fusion is a function of the timing of eye degeneration. Early and rapid eye degeneration (as in Pachón cavefish) likely has a more profound effect on neuromast positioning, and consequential bone fusion patterns. Tinaja and Molino cavefish have slower and more gradual eye regression, likely interfering less with neuromast positioning. This results in fewer approximated neuromasts, and fusions between neighboring facial bones. This study showcases the integrated nature of sensory-skeletal development, a poorly understood phenomenon. Moreover, aberrations impacting this integration-such as eye loss in cave dwelling fish-can lead to remarkable intraspecific (and intra-population) variation.

Dysphagia, a pervasive global health issue, is increasingly prevalent with age (presbyphagia), significantly impacting well-being. Studying its complex mechanisms in humans is challenging, often necessitating animal models. Ideally, such models should combine close anatomical and physiological similarity to humans with practical attributes that facilitate longitudinal research, including ease of handling and housing, manageable lifespan, compressed developmental timelines, and high fecundity. Marmosets (Callithrix jacchus), with their notable human-like similarities and practical advantages, represent an ideal biogerontology model, though their swallowing physiology remains largely underexplored. From a comparative biology perspective, this study aims to elucidate swallowing biomechanics and physiology across the lifespan of healthy captive common marmosets using cineradiographic imaging. We used cineradiography to examine swallowing function and spinal posture in 26 healthy marmosets, ranging from 0 to 19 years old. A high-resolution microfocal X-ray source and beryllium fast-response image intensifier, housed in a radiation-proof chamber, were employed. Animals consumed barium-mixed Castella cake while a dual video camera system captured synchronized visual and audio data. Researchers remotely manipulated the animal cage via an X-ray control desk. We measured bolus size, inter-swallow intervals, pharyngeal inlet angle (PIA), and spinal angles during swallowing. Analyzing 784 swallows from 56 recordings, we found significant age-related differences in bolus size, inter-swallow interval, and PIA (P < 0.001). Elderly marmosets displayed longer inter-swallow intervals, and had wider PIAs than younger animals; poorer dental health also correlated with these changes. Postural analysis revealed older marmosets exhibited more flexed cervicothoracic and thoracolumbar angles and increased spinal sinuosity. Importantly, narrower spinal angles correlated with larger boluses, wider PIAs, and longer inter-swallow intervals. This study provides a comprehensive lifespan investigation of marmoset swallowing, revealing distinct age-related changes in anatomy and swallowing physiology. Our findings significantly advance the understanding of aging in this species and underscore the marmoset's potential as a valuable model for future swallowing research, particularly for investigating disease conditions and testing interventions relevant to human dysphagia.

Outcomes of ecological interactions often depend on the abundance and identity of the organisms involved. Flower-bacteria interactions can strongly affect plant ecology, and the identities of epiphytic flower bacteria are relatively well documented. Yet little is known about how the abundance of epiphytic bacteria on flowers changes over time. In this field study, we quantified how the abundance of culturable epiphytic bacteria on flowers changed as flowers aged and how abiotic factors influenced bacterial abundance and flower longevity. To accomplish this, we sampled flowers from anthesis to senescence of 8 plant species that varied substantially in terms of flower longevity and comprised 8 different genera from 7 different families. As expected, flowers of all plant species accumulated more bacteria with age. However, plant species with longer-lived flowers accumulated bacteria relatively more slowly, suggesting such plant species may have evolved more effective antibacterial defenses. Although elevated temperature is often expected to boost bacterial growth and diminish flower longevity, temperature was negatively associated with both flower longevity and bacterial accumulation, suggesting that changes to flower longevity strongly affect bacterial populations. In contrast, precipitation was positively associated with flower longevity and negatively associated with bacterial accumulation, likely because precipitation reduced plant water stress while also dislodging bacteria from flowers. Finally, we discuss the implications of our results for plant-bacterial-pollinator interactions.

Illegal introductions in North America have helped establish populations of Northern Snakehead (Channa argus), an invasive freshwater fish from Asia. Once targeted for eradication, widespread establishment of populations in the Chesapeake Bay watershed has now led management to prioritize mitigation. One method of mitigation has been harvesting via bowfishing. We measured the influence of bowfishing in the snakehead fishery between 2022 and 2024. Ten charter boat captains who operated bowfishing trips across 17 rivers in 2024 provided 556 trip reports for snakehead trips (March to November) that represented an average of four bowfishing clients (range = 1 client to 12 clients) who fished an average of 4.8 hours (standard error = 0.05) per evening trip (high ebb to slightly beyond low tide). Harvest ranged between 0 fish and 32 fish per river-trip, with an average median of 10 fish (standard error = 2.7). Harvest was greatest in spring and fall (3.5°C < air temperature < 17°C) and full or new moons. Bowfishing and gigging accounted for the majority of annual fishing mortality, which was 19.1% in 2023 and 20.0% in 2024. This was lower than the target of 25% to achieve population declines. Our results highlight both the value of bowfishing and the need to encourage bowfishing as means of harvesting snakeheads in ecosystems.

Evolution on islands often generates specialized lifestyles that are rarely seen in continental species. The biota on oceanic islands are, however, prone to extinctions following human colonization, resulting in an incomplete understanding of the lifestyles of species that evolved prior to colonization. For example, the Hawaiian Islands hosted a unique and diverse assemblage of endemic taxa, most of which became extinct following human colonization. Among these is Apteribis (Threskiornitidae), an extinct genus of flightless ibises for which nothing is known of their behaviour and ecology. To gain insight into the foraging behaviour and activity pattern of this unusual genus, we quantified their olfactory, visual, and somatosensory systems from direct measurements of skulls, CT scans, and endocasts. We then compared Apteribis with extant ibises with phylogeny-informed statistics to determine if they differed significantly in any of our measured traits. Our analyses show that the olfactory and somatosensory systems of Apteribis are comparable in size and anatomy to those of extant ibises and it was likely flexible in terms of preferred foraging habitat. In contrast, the visual system of Apteribis is greatly reduced in size, suggesting a nocturnal lifestyle, which is an unprecedent trait among ibises. Our data therefore suggests that Apteribis occupied a niche similar to that of New Zealand kiwi (Apteryx): nocturnal, flightless species that rely on tactile cues from its beak to detect prey. This study provides the first quantitative evidence for the evolution of a kiwi-like niche for a bird outside New Zealand, and emphasizes the remarkable diversity of avian lifestyles lost due to anthropogenic impact.

The resource strategy of seedlings is an important aspect for understanding the adaptation of trees at this ontogenetic phase to abiotic changes. In this study, we sought to determine the patterns of response of functional traits of a shade-tolerant (Acer platanoides) and a shade-intolerant (Quercus robur) species along natural environmental light gradients. We conducted trait-based analyses at both individual and community levels using direct (leaf area index [LAI] and diffuse noninterceptance [DIFN]) and indirect (light coefficient, derived from Ellenberg values [LC]) methods in the Arboretum at Kórnik (Poland). Differences between the two species were found for some variables. Analysis of phenotypic plasticity indices of leaf, stem, and root traits of seedlings had high values ​​for both species. The values of plasticity indices of A. platanoides root traits were lower compared to the corresponding traits for Q. robur. Relationships between measures obtained from individual-level trait data were stronger than relationships with measures obtained from community-level trait data. The data obtained from the direct method, which included light measurements both at the community level (experimental plots) and at the individual level (seedlings), revealed the closest relationships between functional traits of seedlings and light changes at the individual level trait data for both species. Correlation links between LAI and leaf (leaf mass per area; specific leaf area) and stem (specific stem length; stem mass fraction) traits were less tight for Q. robur compared to A. platanoides. The indirect Ellenberg indicator analysis revealed relationships between LC and leaf mass per area, and stem-to-root ratio of seedlings based on community-level trait data. Close relationships between LC and leaf mass fraction and specific leaf area were not established, in contrast to LAI and DIFN. The closest relationships, representing among traits within the same organ system, and links, describing interactions between traits of different organ systems, were established at the community-level trait data.

Rhagovelia oriander is a freshwater water strider native to the rivers and streams of North and South America, known for its distinctive skating movement on the water's surface. This movement resembles the correlated random-walk pattern seen in microorganisms such as Escherichia coli. Previous studies have primarily focused on limb adaptations and biomechanics, leaving the ecological significance inadequately addressed. We combine field observations with controlled laboratory experiments using a flow mill to investigate the dynamics of R. oriander under typical flow conditions. Our findings indicate that this insect exhibits a two-dimensional run-and-tumble motion, often incorporating lateral tumbles following straight runs (run distance: $30.7pm 9.3$ mm). We find that this behavior is resilient to changes in flow speed. In-silico simulations of particle interception demonstrated that this locomotion method enhances encounter rates compared to linear movement, particularly when the simulated food particle is following a rapid flow field. Our results document run-and-tumble locomotion in a millimeter-scale organism, showcasing a unique example of convergent behavior across diverse taxonomic groups and providing valuable insights into locomotion ecology while serving as a source of inspiration for bioinspired robotics and environmental exploration algorithms.