China stands as a global hotspot for cuckoo diversity and their avian hosts, presenting an unparalleled natural laboratory for investigating brood parasitism and co-evolutionary dynamics in avian systems. Through an extensive synthesis of published literature, verified media reports, and meticulously curated visual documentation contributed by citizen scientists, we present a comprehensive update on cuckoo–host diversity and their intricate ecological relationships across China. Our study identifies 17 cuckoo species, with 15 confirmed as brood parasites exploiting an extensive network of 142 host species spanning 74 genera and 34 families within the passerine assemblage. While we observed broad overlaps in the ranges of host body mass and egg volume across different cuckoo species, phylogenetic generalized linear mixed models reveal significant patterns of adaptive matching in both body mass and egg volume parameters between cuckoos and their respective hosts. Our findings demonstrate striking specificity in host selection, with minimal overlap in actual host species utilization among sympatric cuckoos, suggesting sophisticated niche partitioning strategies to mitigate interspecific competition. Nevertheless, critical knowledge gaps persist, particularly regarding the evolutionary dynamics of egg phenotype mimicry in relation to specific host species. Finally, we introduce a real-time tracking program designed to engage citizen scientists in ongoing documentation of parasitism events, facilitating dynamic updates to host–parasite records.

This paper addresses the population genetic structure of the forest-dwelling gonyleptid Geraeocormobius sylvarum (Arachnida, Opiliones). Phylogeographic analyses using cytochrome oxidase subunit I (COI) were conducted on 186 individuals from 43 localities in Argentina and Paraguay, arranged into nine operational sectors and defined upon geographic and vegetation features. Given the current environmental uniformity, it was aimed to assess whether molecular fingerprints of G. sylvarum correlate with Pleistocene fragmentation events, inferred through forest contraction/expansion cycles. The network of 87 haplotypes displayed an unstructured pattern; 75 were found in unique localities (54 on single individuals), with most haplotypes restricted to a single operational sector. The calibrated phylogenetic tree revealed significant admixture, with each clade mainly related to one operational sector. Results suggest multiple fragmentation events; most COI diversity arose in the Late Pleistocene/Early Holocene; recent and relict lineages coexist at a few sites. Banks of major rivers (Paraná and Uruguay) in Misiones Province may have served as main refuge areas, with dispersal within each basin being frequent but sporadic across the watershed divide, keeping basins separated for long periods. The split of the Misiones opiliogeographical area into two sectors corresponding to the major basins is proposed.

Examining closely related species evolving in similar environments offers valuable insights into the mechanisms driving phylogenetic conservatism and evolutionary lability. This can elucidate the intricate relationship between inheritance and environmental factors. Nonetheless, the precise genomic dynamics and molecular underpinnings of this process remain enigmatic. This study explores the evolutionary conservatism and adaptation exhibited by two closely related high-altitude frog species: Nanorana parkeri and N. pleskei. We assembled a high-quality genome for Tibetan N. pleskei and compared it to the genomes of N. parkeri and their lowland relatives. Our findings reveal that these two Tibetan frog species diverged approximately 16.6 million years ago, pointing to a possible ancestral colonization of high-elevation habitats. Following this colonization, significant adaptive evolution occurred in both coding and non-coding regions of the ancestral lineage. This evolution led to notable phenotypic alterations, as evidenced by the reduced body size. Also, due to purifying selection, most ancestral adaptive features persisted in descendant species, indicating a strong element of evolutionary conservatism. However, descendant species evolved novel adaptations to exacerbated environmental challenges in the Tibet Plateau, mainly related to hypoxia response. Furthermore, our analysis underscores the critical role of regulatory variations in descendant adaptive evolution. Notably, hub genes in networks, such as EGLN3, accumulated more variations in regulatory regions as they were transmitted from ancestors to descendants. In sum, our study sheds light on the profound and lasting impact of genetic heritage on species' adaptive evolution.

Earth has experienced five major global mass biodiversity extinctions, and we are currently facing the sixth, which includes mammals, particularly carnivores, being among the most affected. Studying the remnant populations alone of the currently endangered species often provides limited information. It fails to reveal the scenarios of the early dynamics and key driving facts/factors that led to their population decline. Therefore, a comprehensive understanding of the dynamics of long-term faunal extinction is not just an academic pursuit, but a crucial necessity for developing or amending tangible conservation strategies and management. This study examines the extirpation trajectories of tigers, relying extensively on fossil databases in the Pleistocene and historical geographic changes during the Holocene. We estimated their extinction probability and relationship with anthropogenic and climatic changes using a moving time window modeling framework. It illustrates how the impacts of humans on nature have significantly influenced threatened animals. These human activities will continue to shape the future survival prospects of tigers in China. Our findings indicate that cropland expansion, human population growth, and forest reduction have profoundly driven tiger extinctions, particularly after 1850, when pervasive human activities led to the disappearance of wild South China tigers. We estimate that isolated tiger populations face extinction within roughly 67.8 years, emphasizing the need for habitat connectivity. This study highlights the critical role of reducing human activities in tiger habitats and offers a model for estimating extinction probabilities and thresholds, underscoring the urgency of conservation strategies tailored to anthropogenic and environmental threats.

DNA metabarcoding is revolutionizing biodiversity research by providing rapid and efficient ways of collecting species occurrence data. However, it has not yet been effectively applied to many taxonomic groups, mainly due to a significant lack of reference sequences and dedicated protocols. One such group is the tardigrades—a charismatic phylum of microinvertebrates known for their extremophilic and cryptobiotic capabilities. In this study, we provide the first curated database of 3194 tardigrade COI sequences sourced from public databases and supplemented with newly produced barcodes. We demonstrate tardigrade metabarcoding in action with optimized PCR primers and a sample processing protocol using 78 samples collected in Poland and Italy. The metabarcoding revealed the presence of more than a hundred operational taxonomic units classified as Tardigrada, representing 23 genera. We compared the metabarcoding results with a morphological survey, which revealed the presence of the same genera, but a lower number of species-level taxa identified morphologically. We observed congruent patterns of tardigrade species richness and taxonomic composition between metabarcoding and morphological surveys in both within-sample and regional fauna composition levels. The metabarcoding had a higher discriminatory power, revealing cryptic diversity, and distinguishing species belonging to taxonomically challenging species complexes. By combining metabarcoding with morphological study, we were able to find rare taxa, including novel biogeographic records and putative species new to science, showing also that this approach can be extremely powerful and effective in meiofauna research.

Deep-sea shrimps from the family Alvinocarididae are prominent inhabitants of chemosynthesis-based habitats worldwide. However, their genetic diversity and population connectivity remain poorly understood due to limited sampling. To fill these knowledge gaps, we compared the population genetics of two vent- and seep-dwelling alvinocaridid species with overlapped geographic ranges between the South China Sea and the Manus Basin. Alvinocaris longirostris has a wider distribution, ranging from 35°N to 3°S and at depths of 930 to 1736 m, while Alvinocaris kexueae is more restricted, found between 16°N and 3°S at depths of 1300 to 1910 m. Our analysis, based on the mitochondrial cytochrome c oxidase subunit 1 gene, revealed that A. longirostris had lower genetic diversity and minimal genetic differentiation across eight disjoint vent and seep populations. In contrast, the narrower-distributed A. kexueae exhibited higher genetic diversity and significant genetic differentiation, with stronger gene flow observed from its Haima seep population to the Manus Basin vent population. In addition, both species appear to have experienced population expansion in their recent evolutionary history. These results suggest that A. longirostris and A. kexueae may possess distinct life-history traits that contribute to their differing distribution ranges in the Western Pacific.

The genus Typhlomys comprises six species that all exhibit exceptional climbing agility in arboreal habitats, of which five have been established to use ultrasonic echolocation in the 80–120-kHz frequency range to navigate among tree branches. Here, we investigated the ultrasonic vocalizations of the remaining and recently recognized species, T. fengjiensis, and compared its ultrasonic and morphological traits with its sibling species T. daloushanensis. Both species produced frequency-modulated (FM) ultrasonic calls that lacked harmonic structure, consistent with echolocating calls established for other members of this genus Typhlomys. This FM echolocation call structure is well-adapted to navigating along branches in dense foliage conditions in the forest understory. Importantly, however, the specific call structures of T. fengjiensis and T. daloushanensis exhibited significantly different ultrasonic characteristics, with different numbers of pulse groups, in support of phonic speciation. T. fengjiensis was on average larger than T. daloushanensis and vocalized at a lower frequency and for a longer duration, in support of the signal-size allometry hypothesis. Furthermore, T. fengjiensis has the lowest ultrasonic call frequency among Typhlomys spp., corresponding with it being the largest member of this genus. Bergmann's law does not provide a compelling explanation of the body mass differences between T. fengjiensis and T. daloushanensis, due to the likely overlap in their elevational distribution. Further research is needed to establish if differences in habitat selection and diet, or differences in social and reproductive behavior, might best explain this local species divergence based on phonic traits.

Human activities generally increase trophic overlap in predator guilds through resource subsidies, whereas the effects on whether sympatric species overlap or separate their niches are context-dependent. Mesocarnivores (order Carnivora, Mammalia) are often adaptive and tolerant to human activities, allowing them to establish populations in human-modified landscapes. Here, we examined how trophic niche overlaps between the wide-ranging mesocarnivores, the red fox (Vulpes vulpes) and sympatric martens (genus Martes), are influenced by geo-environmental and anthropogenic factors, using a systematic literature review and meta-analysis at the Eurasian continental scale. We hypothesized that the extent of trophic overlap would increase in areas with greater human disturbance and less productive environments associated with resource availability. We included a total of 35 publications with 76 observations from continental Europe and Japan and then calculated the relative trophic overlap. Their trophic overlaps were relatively high because they shared common resources, such as small mammals, invertebrates, and fruits. Contrary to our predictions, multivariate statistical modeling demonstrated that trophic overlaps declined with increasing human disturbance and decreasing vegetative landscapes. Our findings indicate that human disturbances forced their resource use to separate, potentially due to resource depletion by land modifications and intense human activities, whereas vegetated habitats moderated direct and indirect competition. Based on these results, we conclude that patterns in trophic interactions largely depend on spatiotemporal resource availabilities. We suggest that maintaining regional resource abundance is crucial for successful sympatry in competing carnivores and for balancing stable intraguild interactions in human-modified landscapes.

Aquariums globally have seen significant growth in recent decades. However, persistent negligence exists concerning underwater sound pollution in aquariums and its impact on cetaceans. Here, the audiogram of Taotao, the world's first successfully captive-born and bred Yangtze finless porpoise, and the underwater sound levels in the Baiji Aquarium at the Institute of Hydrobiology, Chinese Academy of Sciences were examined. In contrast to the previously published U-shaped audiograms of the Yangtze finless porpoise, Taotao's audiogram exhibited a W-shaped pattern. Additionally, the audiogram of Taotao was, on average, 42 ± 15 dB (mean ± SD) higher than that of other non-aquarium-born Yangtze finless porpoises in the Baiji Aquarium and 43 ± 11 dB higher than that of wild Yangtze finless porpoises, particularly in the 20–60 kHz range and at 90 kHz. The underwater sound spectra in the Baiji Aquarium do not account for the notches observed in the porpoise's audiogram below 60 kHz, suggesting that congenital hearing disorders may be the cause of Taotao's hearing loss in these frequency bands. In contrast, the cumulative weighted broadband sound exposure levels of underwater sound within the aquarium (mean: 162 dB) exceeded the temporary threshold shift onset threshold for non-impulsive noise (153 dB) and the permanent threshold shift onset threshold for impulsive noise (155 dB) in finless porpoises. The high levels of underwater sound exposure, particularly from conspecific porpoises, highlight the need for increased focus on the welfare of captive animals.

Despite the large amount of video data captured during ethological studies of wild mammals, there is no widely accepted method available to automatically and quantitatively measure and analyze animal behavior. We developed a framework using facial recognition and deep learning to automatically track, measure, and quantify the behavior of single or multiple individuals from 10 distinct mammalian taxa, including three species of primates, three species of bovids, three species of carnivores, and one species of equid. We used spatiotemporal information based on animal skeleton models to recognize a set of distinct behaviors such as walking, feeding, grooming, and resting, and achieved an accuracy ranging from 0.82 to 0.96. Accuracies of validation videos ranged from 0.80 to 0.99. Our study offers an innovative analytical platform for the rapid and accurate evaluation of animal behavior in both captive and field settings.

Recently burnt and logged habitats challenge the persistence of animal populations. Insects like cicadas, which survive belowground during fire and logging, are exposed to hostile conditions due to increased predation and limited resources when they emerge as adults. This study investigates the combined effects of wildfire and post-fire salvage logging on the survival, spatial behavior, and habitat selection of the cicada Lyristes plebejus in Mediterranean pine forests. A total of 63 individuals were captured, tagged, and released across six plots in three disturbance contexts: burnt and logged, burnt and unlogged, and unburnt. Using radio telemetry, we tracked their movements and compared home range size and survival across these contexts. Results show that cicadas in burnt but unlogged areas were more mobile and tended to select areas of lower fire severity compared to those in burnt and logged areas. Salvage logging removed essential fire refuges, increasing exposure to predators. Although no significant differences in total distance covered were found, cicadas in burnt and logged areas displayed lower movement rates, indicating a reduced ability to explore and select suitable habitats. These findings highlight the importance of considering both wildfire and post-fire management practices in conservation. Salvage logging exacerbates the negative effects of fire, emphasizing the need to preserve biological legacies and fire refuges to promote ecosystem resilience. The study suggests that careful forest management is crucial for protecting biodiversity, particularly for species like cicadas that depend on both above and below-ground habitats.

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.

Pomacea canaliculata is recognized as a globally invasive aquatic species. Analyses of intestinal microbiota, dietary composition, and metabolism of invasive species can enhance our understanding of their feeding strategies and physiological adaptation strategies to the environment. Intestinal content samples were collected from P. canaliculata inhabiting three distinct environments including a pond, a river, and a ditch. These samples were subjected to 16S rRNA gene sequencing analysis and multiple metabarcoding analyses, including eukaryotic 18S rRNA, mitochondrial cytochrome c oxidase I (COI), and chloroplast rbcL genes. In addition, metabolomics analysis was conducted on the intestinal content samples to investigate metabolic change. The highest dietary diversity in P. canaliculata was observed in the ditch, and females exhibited a higher dietary diversity than males in the pond. The 18S rRNA gene has a high potential for identifying the dietary components of omnivorous species. The intestinal microbiota of P. canaliculata from different habitats displayed significant variations, attributed to differences in food resources and other environmental factors. Bacteria in the aquatic environment had minimal impact on the intestinal microbiota of P. canaliculata. Overall, P. canaliculata exhibited adaptive changes in physiological characteristics across different habitats, including alterations in diet, which, in turn, influence microbiota and metabolic pathways such as amino acid biosynthesis in the intestine. The present study investigated the physiological mechanisms that enable P. canaliculata to adapt to diverse habitats, considering various factors including diet, which is important for comprehending its invasive potential and the subsequent threats it poses to aquatic ecosystems.

The development of anthropogenic structures in cities has resulted in thermal heterogeneity, potentially affecting the immunological features of urban fauna. In these environments, synanthropic species such as pigeons (Columba livia) exhibit coloration polymorphisms under endocrine regulation mediated by the melanocortin system, which determines several immunological traits. Due to these potential sources of variability, we assessed how habitat influences physiological traits related to immunological features, theoretically affected by feather coloration, while considering other factors such as seasonality, body mass, and sex. This study aimed to determine whether pigeons from locations with different urban temperatures (Santiago, Chile) and color polymorphism exhibited variability in plasma immunoglobulin Y concentration, leukocyte profiles, and the H/L index. The results demonstrate that pigeons exhibit variations in immunological features related to the thermal characteristics of their urban habitats. Specifically, we observed a strong effect of thermal heterogeneity on the H/L ratio, with higher values in areas experiencing warmer temperatures, a relationship dependent on body mass. We also identified differential impacts of seasonality and sex on basophil and monocyte percentages. Regarding humoral immunity, we found a strong effect of environmental temperature and plumage melanism on urban pigeons which was influenced by sex. Our findings contribute to understanding the factors affecting the immune system in urban birds and provide valuable insights into their response to landscape modifications.

The adaptive significance of female ornamentation remains a central question in evolutionary biology, with ultraviolet (UV)-induced fluorescence emerging as a key area of interest. This study investigates the potential adaptive advantages of female-specific UV-induced fluorescence in male mate choice and predation risk, as fitness costs, using two species of ornate jumping spiders Phintella vittata and Ph. bifurcilinea. In these species, the palps of adult females exhibit UV-induced fluorescence, offering a compelling model to explore the interplay of sexual and natural selection acting on female ornamentation. In male mate-choice trials, males were presented with a choice between a fluorescent (F+, UV-visible) and a non-fluorescent (F–, UV-blocked) female. Males showed pronounced mate preference for F+ females over F– females, that is, spending significantly more time interacting with F+ females, suggesting that fluorescence serves as a sexually selected signal. To assess the potential costs of fluorescence, we tested its effect on predation risk using the spider-eating jumping spider Portia xishan as a predator under F+ and F– conditions. Predation rates were significantly higher for F+ females than for F– females, indicating that UV-induced fluorescence increases detectability by predators. These findings provide empirical evidence of a trade-off: While fluorescence enhances male mate preference, it also increases predation risk. This study is the first to demonstrate the dual roles of fluorescence in sexual signaling and predation in female jumping spiders, challenging traditional male-centric perspectives on mate choice. By integrating behavioral and ecological approaches, this work offers new insights into the evolutionary trade-offs associated with female sexually selected traits.

Social advancement and heightened waste discharge have resulted in escalating ammonia pollution in aquatic ecosystems, presenting toxicity hazards to aquatic fauna, especially turtles, by impairing their neurological function. To assess the ammonia effect on turtle brains, we subjected Chinese striped-necked turtles (Mauremys sinensis) to varying ammonia concentrations (CK, control; A1, 0.790 mg/L NH3; A2, 1.418 mg/L NH3) for durations of 24 and 48 h. Our data indicate that ammonia exposure markedly elevated glutamate levels and glutamate receptor mRNA expression in turtle brains, while concurrently diminishing glutamate transporter expression. These alterations resulted in an increase in brain water content, Na⁺-K⁺-Cl⁻ cotransporter 1 (NKCC1), and matrix metalloproteinases. The decrease in tight junction proteins and Caveolin1 levels may lead to the rupture of the blood–brain barrier and subsequent edema. The impaired blood–brain barrier and edema led to elevated calcium levels and decreased function of certain ATPases. Gene expression associated with calcium homeostasis increased, signifying an imbalance. As the exposure time and concentration of ammonia increased, the TUNEL-stained positive cells began to appear. Taken together, increased ammonia concentrations lead to glutamate accumulation, impairing the blood–brain barrier and resulting in cerebral edema. This impairs calcium homeostasis, ultimately inducing cell death. This work provides significant insights into the toxicity of ammonia to aquatic turtles, hence augmenting our comprehension of stress physiology in these species. It underscores the necessity of safeguarding aquatic ecosystems from ammonia contamination to guarantee the health and survival of turtles and other aquatic fauna.