Integrative zoology最新文献

As natural science research penetrates further into the microscopic world, the biological discipline has an increasing demand for tools to observe sub-micrometer structures such as cell structure and biomolecule assembly. Electron microscopy imaging has emerged as a pivotal method for such observations, yet accurate identification remains challenging due to the high density, mutual occlusion, small size, and diverse postures of the targets. To date, no research has systematically addressed these issues, limiting progress in biological microscopic research. Here, we introduce an improved YOLOv8n model for detecting the bird feather hooklet, a typical microscopic target within electron microscope images. The improved model incorporates three modules: gather-excite attention mechanism (global-local feature integration), explicit visual center (EVC) module (small-object detection enhancement through global and local feature fusion), and Shape IoU loss function (bounding-box regression optimization for posture variations). The experimental outcomes demonstrate that, compared to the baseline model, the improved YOLOv8n achieves a 3.5% increase in precision, a 9.1% boost in recall, and a 5.7% improvement in mAP50, along with 4.4% and 6.3% gains in mAP50-95 and F1 score, respectively. These advancements demonstrate the improved YOLOv8n model's effectiveness in detecting occluded, aggregated, and multi-posed hooklets at the nanometer level, offering new insights into feather structure-function relationships and advancing ornithological research. This study not only highlights the great potential of the improved YOLOv8n model in complex object detection but also emphasizes its application significance in micro-precision biological research.

Sex ratio is an important population metric in animal conservation, but its study in marine species with low sexual dimorphism is often challenging. This work aimed to apply the principles of skin mark analysis to a cetacean species to test its ability to identify sex differences in markings and build a sex-discrimination model exclusively based on photographic material. The common bottlenose dolphin (Tursiops truncatus) was chosen as the model species, and skin marks and their progression over time were identified and measured across the whole-body surface of individuals on photographs acquired between 2016 and 2023 in the Tiber River Estuary area. Interactions with fisheries were quantified both as the proportion of encounters in presence of trawlers, and as a probability of fishing gear injuries. Non-parametric tests were used to assess sex-specific differences. A generalized linear model with binary response (sex) was built through a stepwise procedure, using mark-based indices as predictors. Relevant differences between sexes emerged in markings, with males presenting more social, aggression-related, and fishing-related marks overall, and a stronger tendency of mark accumulation over time. The estimated model reflected the differences highlighted by the statistical tests and had a high accuracy and sensitivity toward both sexes. These results highlight the feasibility and efficacy of this methodological approach to sex-ratio investigations and identify differences in anthropic pressures insisting on males and females, with important conservation implications. The exclusive use of photographic material makes this methodology potentially applicable and adaptable to multiple species and environments, aiding the efforts of conservationists worldwide.

Male weaponry evolution is often linked to male-male competition for resources or access to females, a pattern observed in well-studied taxa, such as beetles and mammals. Whether factors such as breeding site type influence weaponry evolution remains an open question. We explored this question using frogs of the subfamily Leptodactylinae, where males of species that spawn in exposed sites (water bodies) fight to hold oviposition sites or dislodge rivals during amplexus. Conversely, males of species that spawn in concealed sites (ground nests and crevices) rarely engage in physical contests. We hypothesized that male weaponry evolution would be associated with reproduction in exposed sites. Using two complementary phylogenetic comparative methods, we first found that both gains and losses of weapons occurred more frequently in species spawning in exposed sites. This unexpected finding suggests that the dynamics of weaponry evolution are more intricate than anticipated. Second, we found a macroevolutionary correlation between male weapons and breeding site type: the presence of weapons is associated with exposed sites, while their absence is associated with concealed sites. We explore how additional factors, such as population density, the energetic costs of producing and maintaining weapons, and female choice, may also influence this macroevolutionary pattern. Finally, we hope our findings stimulate further investigations into weaponry evolution in other clades of external fertilizers.

The social brain hypothesis predicts that the relative size of specific brain regions is driven by the cognitive capacity required to manage complex (social) situations. Spiders are intriguing models to test this hypothesis, as sociality is rare in this usually solitary and aggressive group. Here, we used microCT to compare the central nervous system and brain volumes between social and solitary females of the species in two taxonomic groups, huntsman and crab spiders. Overall, we found no difference in relative CNS and brain volume between social and solitary species. However, social huntsman spiders Delena cancerides had larger arcuate and mushroom bodies than the solitary huntsman species Isopeda villosa and Heteropoda jugulans. Social crab spiders Xysticus bimaculatus had larger visual neuropils than the solitary species Thomisus spectabilis and Tharrhalea evanida. Social huntsman spiders exhibit intricate social behavior, including prey sharing and kin recognition, which could explain the higher investment in brain structures that are related to cognitive integration. They also had smaller venom glands, possibly due to their prey-sharing behavior. In social crab spiders, the low-light leafnest may have driven enlarged visual neuropils. Some variations in specific brain regions between solitary and social species were consistent with the social brain hypothesis, but the patterns differed between lineages. Thus, it is likely that other ecological drivers affect the development of specific brain regions in spiders. Our study provides the essential knowledge platform to conduct experimental manipulations of social and environmental conditions on these spiders to directly test their impact on brain structures, coupled with tests of relevant behavior.

In the last 30 years, the area of the study of parasitism caused by blood parasite infections on wildlife has suffered an extraordinary transformation. We will review here some of the advances produced in three specific aspects: (1) Taxonomy; this field has been profoundly transformed, moving from microscopy to molecular analyses and phylogeny. (2) Impact of infections on wildlife fitness; from an initial position in which it was understood that infections by blood parasites had little or no effect on their hosts, we have moved on to the experimental demonstration of important effects on the fitness of individuals. (3) Distribution of blood parasite infections; the distribution across latitudinal and altitudinal gradients as well as the different effects of anthropic activities on the incidence of blood parasite infections have been developed importantly during the last few years. Finally, we will look at the promising future of this discipline by pointing out some developing fields of research.

Chemical signal perception plays a crucial role in arthropod reproduction and survival. The scorpion is one of the oldest terrestrial arthropods; however, its knowledge of the chemosensory genes remains unclear. Based on the transcriptomic analysis of widely distributed Mesobuthus martensii in China, 46 candidate gustatory receptors (GRs) and 80 candidate ionotropic receptors (IRs)/ionotropic Glutamate receptors (iGluRs) overall showed similar expression trends in different tissues between the third-instar and adult scorpions, which suggested that young scorpions possessed a relatively complete chemical perception capability. Most GRs showed higher transcript accumulation in the pectines, rather than other tissues, aligning with their known chemosensory function and highlighting the remarkable significance of pectines as crucial sensory organs. Conversely, IRs/iGluRs overall exhibited a more widespread distribution throughout the different tissues of the scorpion body. The phylogenetic tree further elucidated the evolutionary relationships among these chemosensory genes in arthropods. These findings contributed to a better understanding of the functionality and evolution of the chemosensory systems in scorpions, which would accelerate the functional investigations of scorpion chemosensory genes in the future.

Octocrylene (OC) and ethylhexyl salicylate (EHS), widely used organic ultraviolet (UV) filters, are persistently detected in natural environments, raising concerns about their ecological toxicity. However, their toxicity at environmentally relevant concentrations remains poorly understood, and a comparative assessment of their aquatic effects is lacking. This study exposed zebrafish embryos (≤4 h post-fertilization, hpf) to OC and EHS (0.05, 0.5, 5, and 50 mg/L) until 120 hpf. Both chemicals induced developmental abnormalities, including deformities and reduced heart rates. Exposure to 50 mg/L EHS resulted in 54.72% mortality, while the same concentration of OC caused 13.33% mortality at 96 hpf, indicating higher acute toxicity of EHS. Behavioral assays revealed that 50 mg/L OC and 5 mg/L EHS induced hyperactivity, whereas 50 mg/L EHS caused locomotor suppression, suggesting neurodevelopmental toxicity. Transcriptomic analysis showed OC regulated hypoxia response, cytochrome P450, and extracellular matrix, while EHS affected immunity, nucleotide/amino-sugar metabolism, and lipid homeostasis. Oxidative stress biomarkers (superoxide dismutase, glutathione peroxidase, and glutathione) and triglyceride (TG) levels were monitored. Both chemicals induced oxidative stress, but only EHS significantly upregulated TG, disrupting lipid metabolism. These findings highlight that EHS exhibits broader and more severe toxicity than OC, emphasizing the need for further research and regulatory measures to mitigate the ecological risks of these UV filters.

Body size and dietary breadth are important for understanding animal evolution and adaptation. Snakes, as ecologically diverse predators with wide variation in morphology, reproduction, and diet, provide an excellent species group to explore how venom, reproductive mode, and biogeographical traits shape the evolution of ecological traits and dietary breadth. In this study, we compiled a global dataset of 4190 snake species and applied phylogenetically informed models to examine how traits such as venom, litter size, reproductive mode, and biogeographical characteristics across their geographic ranges (temperature, precipitation, and NDVI) influence body size and dietary breadth. We found that larger body size was consistently associated with greater dietary breadth, larger litter sizes, warmer climate, and higher vegetation. Dietary breadth, as an ecological outcome shaped by intrinsic functional traits, increased with venom, higher litter size, colder climate, and broader range size, though these effects varied across genera. Trait-function relationships were also influenced by ecological conditions: Body size increased more pronouncedly with both higher dietary breadth and vegetation in invertebrate-aquatic predators; the reduction in dietary breadth associated with warmer climates was more pronounced in open-canopy than forest-dwelling species. These findings show that ecological factors drive trait evolution in snakes by influencing body size and shaping dietary breadth. Our results could provide implications for snake conservation under global change by identifying trait combinations (e.g., small body size, narrow dietary breadth, limited range) that may increase vulnerability to climate-driven range shifts and help prioritize vulnerable lineages for conservation.

Understanding the mechanisms shaping biodiversity distribution patterns is essential in ecology, and species distributions are closely influenced by environmental factors. Previous studies have often focused on taxonomic levels, potentially overlooking important within-group ecological variations. Anurans, with six distinct ecotypes, each occupying unique habitats, serve as an ideal model to examine how environmental factors shape these ecotype-specific distributions. Here, we investigated the global distribution and environmental determinants of anuran ecotypes to reveal diversity patterns, assess their contributions to overall anuran richness, and identify key environmental drivers. Using microhabitat and geographic data from 6088 anuran species, we mapped the richness and relative richness of each ecotype and evaluated the correlation between ecotype distributions and overall anuran diversity. We further used a random forest model to analyze the impact of environmental factors on the distribution patterns of each ecotype. The results showed significant diversity and distributional differences across ecotypes. Terrestrial and arboreal species, comprising 38.44% and 41.19% of total richness, respectively, contributed strongly to anuran diversity patterns (correlation up to 0.96), while other ecotypes showed weaker correlations. The impacts of environmental factors varied across ecotypes and even had contrasting effects among them. Our findings underscore the importance of accounting for ecotype differences within taxa to accurately understand biodiversity distribution patterns, as environmental influences on anuran diversity are strongly ecotype-dependent.