Integrative and Comparative Biology最新文献

To navigate complex terrains, insects use diverse tarsal structures (adhesive pads, claws, spines) to reliably attach to and locomote across substrates. This includes surfaces of variable roughness and inclination, which often require reliable transitions from ambulatory to scansorial locomotion. Using bioinspired physical models as a means for comparative research, our study specifically focused on the diversity of tarsal spines, which facilitate locomotion via frictional engagement and shear force generation. For spine designs, we took inspiration from ground beetles (Family Carabidae), which is a largely terrestrial group known for their quick locomotion. Evaluating four different species, we found that the hind legs host linear rows of rigid spines along the entire tarsus. By taking morphometric measurements of the spines, we highlighted parameters of interest (e.g., spine angle and aspect ratio) in order to test their relationship to shear forces sustained during terrain interactions. We systematically evaluated these parameters using spines cut from stainless steel shim attached to a small acrylic sled loaded with various weights. The sled was placed on 3D-printed models of rough terrain, randomly generated using fractal Brownian motion, while a motorized pulley system applied force to the spines. A force sensor measured the reaction force on the terrain, recording shear force before failure occurred. Initial shear tests highlighted the importance of spine angle, with bioinspired anisotropic designs producing higher shear forces. Using this data, we placed the best (50○ angle) and worst (90○ angle) performing spines on the legs of our insect-scale ambulatory robot physical model. We then tested the robot on various surfaces at 0, 10 and 20○ inclines, seeing similar success with the more bioinspired spines.

The extent to which evolution is predictable is a long-standing question in biology, with implications for urgent biological issues such as viral evolution, the emergence of antibiotic resistance in bacteria, and organismal responses to climate change. Convergent evolution, the phylogenetically independent evolution of similar phenotypes, provides biological replicates useful for exploring patterns of predictability in evolution. Understanding evolutionary convergence requires synthesizing findings across biological scales and organisms. To this end, we organized a SICB-wide symposium entitled "Integrating research on convergent evolution across levels of biological organization, organisms, and time". Our symposium showcased interdisciplinary research on evolutionary convergence across diverse study systems and levels of biological organization, while highlighting new techniques and comparative methods for identifying patterns of predictability in convergently evolved traits. Here, we introduce findings from papers included in this symposium issue and identify common themes, highlight emerging questions, and discuss how we can integrate new techniques, tools, and systems to expand our understanding of evolutionary convergence.

The morphology-performance-fitness paradigm has long been a guiding principle inspiring a great deal of laboratory and field studies fundamental to understanding functional-morphology relationships across the tree of life. Despite the power of experimental approaches they also come with inherent limitations associated with equipment and animal costs, as well as ethical considerations for the types of manipulations that can be implemented. Modeling can provide an opportunity to surmount some of these challenges by offering greater flexibility in manipulating variables and exploring a wider parameter space than is tractable during animal experimentation. However, effective implementation of these tools requires careful consideration of the limitations and benefits they convey, requiring both greater interdisciplinary training from early stages of educational development and increased collaboration and synergies among scientists from traditionally separate disciplines. With institutions increasingly recognizing the need for and investing in providing universal access to computational and rapid prototyping resources, we believe that it is an opportune moment to prioritize greater synergy to accelerate discovery and innovation across fields.

When cultural biases pervade communication, whether visual or text-based, objectivity is impaired. Anthropocentrism (human-centered bias) and androcentrism (male-centered bias) in particular distort perspectives in mammalian reproductive biology. This paper provides a resource for professionals who understand how cultural biases can be reinforced with language, visuals, and conceptual framing. After brief explanations, we present neutral alternatives to biased terminology as well as ways to avoid bias in illustrations. Since this paper is animal-centric, we hope to inspire the creation of similar resources across a more diverse biota and, thus, move towards a more neutral perspective across reproductive biology.

Birds exhibit a variety of migration strategies. Because sustained flapping flight requires the production of elevated levels of energy compared to typical daily activities, migratory birds are well-documented to have several physiological adaptations to support the energy demands of migration. However, even though mitochondria are the source of ATP that powers flight, the respiratory performance of the mitochondria is almost unstudied in the context of migration. We hypothesized that migratory species would have higher mitochondrial respiratory performance during migration compared to species that do not migrate. To test this hypothesis, we compared variables related to mitochondrial respiratory function between two confamilial bird species-the migratory Gray Catbird (Dumetella carolinensis) and the non-migratory Northern Mockingbird (Mimus polyglottos). Birds were captured at the same location along the Alabama Gulf Coast, where we assumed that Gray Catbirds were migrants and where resident Northern Mockingbirds live year-round. We found a trend in citrate synthase activity, which suggests that Gray Catbirds have a greater mitochondrial volume in their pectoralis muscle, but we observed no other differences in mitochondrial respiration or complex enzymatic activities between individuals from the migrant versus the non-migrant species. However, when we assessed the catbirds included in our study using well-established indicators of migratory physiology, birds fell into two groups: a group with physiological parameters indicating a physiology of birds engaged in migration and a group with the physiology of birds not migrating. Thus, our comparison included catbirds that appeared to be outside of migratory condition. When we compared the mitochondrial performance of these three groups, we found that the mitochondrial respiratory capacity of migrating catbirds was very similar to that of Northern Mockingbirds, while the catbirds judged to be not migrating were lowest. One explanation for these observations is these species display very different daily flight behaviors. While the mockingbirds we sampled were not breeding nor migrating, they are highly active birds, living in the open and engaging in flapping flights throughout each day. In contrast, Gray Catbirds live in shrubs and fly infrequently when not migrating. Such differences in baseline energy needs likely confounded our attempt to study adaptations to migration.

The evolution of the distinct chordate body plan has intrigued scientists for over a hundred and seventy years. Modern genomics and transcriptomics have allowed the elucidation of the Developmental Gene Regulatory Networks (GRNs) underlying the developmental programs for particular tissues and body axes in invertebrates and vertebrates. This has been most revealing in the Deuterostomia, the superphylum in which chordates evolved. The time was ripe to gather those working on deuterostome developmental GRNs to revisit the development and evolution of chordates and discuss the evolution of this unique body plan at the SICB 2024 meetings in Seattle, WA. It has been several years since the genomes of the major deuterostome clades have been sequenced - echinoderms, hemichordates, tunicates, lancelets and vertebrates. Genomic analyses have shown that lancelets have a genome and body plan that closely resemble the vertebrates, although phylogenomic analyses suggest that the tunicates are the sister group of the vertebrates. The evolution of the sessile and sometimes colonial adult tunicates was likely from a motile, lancelet-like ancestor. Scientists from all over the world converged at the SICB meetings in Seattle to discuss the current ideas of how chordates evolved. Some common mechanisms and themes emerged and are captured in this ICB volume on Chordate Origins, Evolution and Development.

Throughout their lives, organisms must integrate and maintain stability across complex developmental, morphological, and physiological systems, all while responding to changing internal and external environments. Determining the mechanisms underlying organismal responses to environmental change and development is a major challenge for biology. This is particularly important in the face of the rapidly changing global climate, increasing human populations, and habitat destruction. In January 2024, we organized a symposium to highlight some current efforts to use modeling to understand organismal responses to short- and long-term changes in their internal and external environments. Our goal was to facilitate collaboration and communication between modelers and organismal biologists, which is one of the major aims of the Organismal Systems-type Modeling Research Coordination Network, OSyM. Accompanying this introduction are a series of papers that are aimed to enhance research and education in linking organismal biology and modeling and contribute to building a new community of scientists to tackle important questions using this approach.