Integrative and Comparative Biology最新文献

Wingbeat frequency estimation is an important aspect for the study of avian flight, energetics, and behavioral patterns, among others. Hummingbirds, in particular, are ideal subjects to test a method for this estimation due to their fast wing motions and unique aerodynamics, which results from their ecological diversification, adaptation to high-altitude environments, and sexually selected displays. Traditionally, wingbeat frequency measurements have been done via "manual" image/sound processing. In this study, we present an automated method to detect, track, classify, and monitor hummingbirds in high-speed video footage, accurately estimating their wingbeat frequency using computer vision techniques and signal analysis. Our approach utilizes a zero-shot learning algorithm that eliminates the need for labeling during training. Results demonstrate that our method can produce automated wingbeat frequency estimations with minimal supervision, closely matching those performed by trained human observers. This comparison indicates that our method can, in some scenarios, achieve low or zero error compared to a human, making it a valuable tool for flight analysis. Automating video analysis can assist wingbeat frequency estimation by reducing processing time and, thus, lowering barriers to analyze biological data on fields such as aerodynamics, foraging behavior, and signaling.

The cost of supporting traits that increase mating opportunities and maximize the production of quality offspring is paid in energy. This currency of reproduction is enabled by bioenergetic adaptations that underlie the flexible changes in energy utilization that occur with reproduction. This review considers the traits that contribute to variation in the capacity of an organ to produce ATP. Further, it synthesizes findings from studies that have evaluated bioenergetic adaptations to the production of sexually selected traits and performance during reproduction and the role of change in mitochondrial respiratory performance in the tradeoff between reproduction and longevity. Cumulatively, these works provide evidence that in selecting for redder males, female finches will likely mate with a male with high mitochondrial respiratory performance and, potentially, a higher probability of mitonuclear compatibility. Females from diverse taxa allocate more to reproduction when the respiratory performance of mitochondria or density of the inner mitochondrial membrane in the liver or skeletal muscle is higher. Finally, reproduction does not appear to have persistent negative effects on mitochondrial respiratory performance, countering a role for mitochondria in the trade-off between reproduction and longevity. I close by noting that adaptations that improve mitochondrial respiratory performance appear vital for optimizing reproductive fitness.

Hybridization is important in evolution, because it is a necessary (though not sufficient) step in the introgression of potentially adaptive variation between species. Bindin is a gamete recognition protein in echinoids and asteroids, capable of blocking cross-fertilization between species to varying degrees. Four species of the sea urchin genus Diadema are broadly sympatric in the Indo-Pacific: D. paucispinum, D. savignyi, D. clarki, and D. setosum. Data from three published studies, one of identification of hybrids through allozymes, one of the phylogeography of mitochondrial DNA, and one of the phylogeny of bindin, were combined to assess the degree of bindin introgression between these four species. I analyzed sequences of the ATPase 8 and ATPase 6 mitochondrial genes and of bindin, sampled throughout the species ranges, with an isolation-migration algorithm, IMa3. IMa3 uses a coalescent approach to produce Bayesian estimates of effective population sizes and gene flow between populations. The results showed that bindin alleles coalesce completely within the species bounds of D. clarki and of D. setosum. The sister species D. paucispinum and D. savignyi, however, were estimated as having exchanged a bindin allele at an average of every one to two-and-a-half generations since they speciated from each other. As the allozyme study detected nine hybrids between three of these species in Okinawa (most of them between D. setosum and D. savignyi) in a single sample, hybrids between these species are produced, but bindin does not introgress. Therefore, bindin must not be efficient in blocking heterospecific fertilizations. Complete, or almost complete, reproductive isolation between species of Diadema must result from low hybrid fitness.

Avian migration is among the most energetically demanding feats observed in animals. Studies evaluating the physiological underpinnings of migration have repeatedly shown that migratory birds display numerous adaptations that ultimately supply the flight muscle mitochondria with abundant fuel and oxygen during long-distance flights. To make use of this high input, the organs and mitochondria of migrants are predicted to display several traits that maximize their capacity to produce adenosine triphosphate (ATP). This review aims to introduce readers to several mechanisms by which organs and mitochondria can alter their capacity for oxidative phosphorylation and ATP production. The role of organ size, mitochondrial volume, substrate, and oxygen delivery to the electron transport system are discussed. A central theme of this review is the role of changes in electron chain complex activity, mitochondrial morphology and dynamics, and supercomplexes in allowing avian migrants and other taxa to alter the performance of the electron transport system with predictable shifts in demand. It is my hope that this review will serve as a springboard for future studies exploring the mechanisms that alter bioenergetic capacity across animal species.

Purple sea urchins (Strongylocentrotus purpuratus) profoundly impact nearshore rocky coasts through their feeding habits. Their intense grazing sculpts substrates through bioerosion using their teeth and spines and controls the alternative stable state dynamic between kelp bed and urchin barrens. These states have contrasting food availability for sea urchins, with abundant food in kelp beds and scarce food in barren grounds. However, the relationship between food availability and bioerosion is unknown. We predicted that when kelp is available, it would ameliorate the action of teeth on the substrate. Our 11-week long, 2 × 2 factorial experiment, crossed community state (kelp present vs absent) and rock type (sandstone vs mudstone). We also quantified the contribution of spine abrasion to bioerosion on the two rock types. The bioerosion rates did not differ between treatments with and without kelp. Although there was no significant difference in net bioerosion between the rock types, there was a large difference between the proportion of bioerosion from teeth vs spine abrasion. Approximately a third of the sandstone bioerosion was from spines whereas less than 2% of mudstone bioerosion could be attributed to spines. As anticipated, growth of sea urchins fed kelp ad-libitum was higher than food-limited sea urchins. Surprisingly, sea urchins on mudstone (which has a higher organic component) grew faster than sea urchins on sandstone. Although bioerosion rates may not differ on a per-urchin basis between community states, the sea urchin population densities between kelp beds and urchin barrens likely causes a difference in net bioerosion between these communities. Our results point to the importance of lithology on the mechanics of sea urchin bioerosion. Differences in texture, grain size, and hardness of rock substrates undoubtedly contribute to bioerosion rates and dynamics.

Inclusive teaching is teaching in a way that reaches all students in the classroom; this is beneficial for everyone, particularly for those with minoritized identities. Instructors play a critical role in scaffolding how students are exposed to and learn science content in the classroom. In this manuscript, we discuss how biology instructors can make their classrooms more inclusive with regard to sex and gender diversity content. Many topics in biology are based on androcentric, heteronormative, and oppressive framing, even though those lenses are more reflective of our own history and culture than they are of the diversity we see in nature. Here, we summarize information presented in the SICB 2024 workshop titled "Incorporating sex diversity and gender inclusivity in biology undergraduate classrooms" and provide instructors with (a) rationale for why inclusive teaching matters, (b) guidance on how to challenge unscientific views and make their curricula more sex diverse and gender inclusive, and (c) practical and easy-to-implement strategies for discussing "contentious" topics in the classroom. Incorporation of this material will be beneficial for students, for science and medicine, and for accurately representing the diversity found across the tree of life.

Trade-offs resulting from the high demand of offspring production are a central focus of many subdisciplines within the field of biology. Yet, despite the historical and current interest on this topic, large gaps in our understanding of whole-organism trade-offs that occur in reproducing individuals remain, particularly as it relates to the nuances associated with female reproduction. This volume of Integrative and Comparative Biology (ICB) contains a series of papers that focus on reviewing trade-offs from the female-centered perspective of biology (i.e., a perspective that places female reproductive biology at the center of the topic being investigated or discussed). These papers represent some of the work showcased during our symposium held at the 2024 meeting of the Society for Integrative and Comparative Biology (SICB) in Seattle, Washington. In this roundtable discussion, we use a question-and-answer format to capture the diverse perspectives and voices involved in our symposium. We hope that the dialogue featured in this discussion will be used to motivate researchers interested in understanding trade-offs in reproducing females and provide guidance on future research endeavors.

Corticosterone, the main glucocorticoid in birds, is a major mediator of the incredible physiological feat of migration. Corticosterone plays important roles in migration, from preparation to in-flight energy mobilization to refueling, and corticosterone levels often show distinct elevations or depressions during certain stages of the migratory process. Here, we ask whether corticosterone's role in migration shapes its modulation during other life-history stages, as is the case with some other phenotypically flexible traits involved in migration. Specifically, we use a global dataset of corticosterone measures to test whether birds' migratory status (migrant versus resident) predicts corticosterone levels during breeding. Our results indicate that migratory status predicts neither baseline nor stress-induced corticosterone levels in breeding birds; despite corticosterone's role in migration, we find no evidence that migratory corticosterone phenotypes carry over to breeding. We encourage future studies to continue to explore corticosterone in migrants versus residents across the annual cycle. Additionally, future efforts should aim to disentangle the possible effects of environmental conditions and migratory status on corticosterone phenotypes; potentially fruitful avenues include focusing on regions where migrants and residents overlap during breeding. Overall, insights from work in this area could demonstrate whether migration shapes traits during other important life stages, identify tradeoffs or limitations associated with the migratory lifestyle, and ultimately shed light on the evolution of flexible traits and migration.

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.