Abstract:[Objectives] Cognition plays an important role in many ecological processes across animals. Growing evidence has indicated individual differences in cognitive performances across multiple species, and the cases of this phenomenon have shown mixed results. However, most of these studies focused on discrete cognitive task or certain limited factors, which may lead to bias. The aims of this study are two-fold: (1) investigate the effects of personality traits (neophobia and exploration), sex, and body characteristics on four general cognitive tasks; (2) investigate whether performances in problem-solving tasks are associated with personality traits, sex, and body characteristics. [Methods] We conducted a series of cognitive experiments to investigate the effects of sex, tarsus length, head volume, and personality traits (exploration and neophobia) on general cognitive tasks and problem-solving performances of budgerigars (Melopsittacus undulatus). Apparatuses with two levels of difficulty were used to measure the problem-solving performances of budgerigars. Exploration behavior was measured in a closed apparatus (L × W × H: 120 cm × 65 cm × 65 cm), which included five artificial trees (height × diameter: 50 cm × 1.5 cm) with two branches (one at the height of 25 cm and one at the top; Fig. 1a). A transparent acrylic sheet was covered on the apparatus top for recording. Budgerigars were caught via flight cages and placed in small cages (L × W × H: 29.3 cm × 22.5 cm × 28 cm), which were coved with black cloth to keep the light out. After 10-min acclimatization, the cage door was opened, and behavior was immediately recorded for 2 min when a budgerigar entered the apparatus. The sum of the walking, flying, and jumping behaviors of each bird in 2 min was regarded as the exploratory score. The test was conducted three times, with the intervals being more than 15 d. In the neophobia test, we recorded the time before individuals began to touch the apparatuses in inhibitory control and associative learning tasks, which were regarded as individuals’ neophobia of different experimental apparatuses. The inhibitory control ability was tested by a detour reaching task. The apparatus consisted of a transparent open-ended cylinder (length × diameter: 7 cm × 7 cm) in which a food reward was placed in the center (Fig. 1b). A lead block was placed at the bottom of the apparatus, which could prevent the bird from easily moving. In each trial, an attempt was considered as successful when the individual detoured the ends of the apparatus without pecking the transparent wall three times. The test was conducted 10 times, with each lasting for 1 min. The number of successful times was seemed as the score in this task. Individuals with high scores were considered to have a better performance in inhibitory control, while a low score indicated poorer performance. The associative learning was tested by a color discrimination task. The apparatus was a rectangular block of wood (L × W × H: 15 cm × 6 cm × 3 cm) with two wells (diameter × depth: 2 cm × 1 cm; Fig. 1c). The wells were covered with dark green and light green lids. In the first trial, an individual needed to open both of the lids and find the food reward, and the reward color was set in light green. The trials were no more than 50 times per day, with the interval of 1 min. If the bird chose the wrong well, the apparatus was immediately removed and the next trial was conducted 1 min later. The individuals were regarded as pass the associative learning task when they found the correct reward well on eight of nine consecutive attempts. The total number of attempts made by the budgerigar was counted as the score for this experiment. A low score indicates better performance in associative learning, while a high score indicates poorer performance. The reversal learning task began 24 h later when the associative learning task was finished. In this task, the food reward was in the dark green well and other experimental procedures were same as those in the associative learning task. The total number of attempts made by the budgerigar was counted as the score for this test. Individuals with low scores are considered to have a better performance in reversal learning, while a high score indicates poorer performance. The spatial memory task was conducted with a rectangular board, which contained 8 wells with blue lids (L × W × H: 20 cm × 15 cm × 3 cm; Fig. 1d). Individuals needed to open the correct lid to get the food reward randomly placed into the well. This test encompassed four phases. In the first phase, individuals had to open the blue lids to search for the reward well. Once they found the correct well and ate the food, the board was removed. After a 5-min interval, the second phase began, with the food reward well being the same as that in the first phase. The first and second phases were training phases that allowed budgerigars to remember the correct reward well. The third and fourth phases were test phases with a 24-h interval, and these two phases were carried out 24 h and 48 h after the second phase, respectively. Budgerigars need to use their memory from the training phases to find the correct rewarded well. If they did not find the reward well within 2 h of the testing phase, we regarded these individuals as non-solvers, and the maximum score in this phase was recorded. The total number of lids opened by budgerigars in the third and fourth phases before they found the correct well was taken as the memory score, and the maximum score was 14. Individuals with low scores were considered to have a better performance in the spatial memory task, and high scores indicate poorer performance. The problem-solving task was carried out via two tests with different apparatuses. The apparatuses were categorized into two types, simple and complex, basing on different levels of difficulty. The simple apparatus was a petri dish with food reward (lid diameter: 70 mm; Fig. 1e), and individuals needed to open the petri dish to obtain the food reward by bill. The complex apparatus was a cuboid made of transparent acrylic sheets with an open end (L × W × H: 15 cm × 6 cm × 6 cm). Inside the complex apparatus was placed a small box with a flat stick that can be pulled out (Fig. 1f). The criterion for the success of this task was that the individuals had to use the stick to pull the box out of the apparatus and then open the lid on the box to obtain the food reward. The simple and complex apparatuses were respectively placed into the cages for 4 days (2 h from 9:00 to 11:00 and 2 h from 15:00 to 17:00 per day), and each apparatus needed to be tested for 16 h. If the individual fails to solve the problem within 16 h, the test will be deemed a failure. The number of attempts, the time before touching the apparatus, and the time to successfully opening the apparatus in problem solving tasks were recorded. In the exploration test, a linear mixed model was employed to calculate the individual repeatability of the exploration. To meet the normal distribution, exploration scores were square-root transformed and used as the response variable. The order (test sequence), sex, time, and date (days since January 1) were used as independent variables. The R package ‘rptR’ was used for data analysis. Then, the Best Linear Unbiased Prediction (BLUP) for each individual was calculated 1 000 times via the R package ‘arm’. In subsequent analyses, the mean BLUP values were used as exploration scores. In the spatial memory task, to demonstrate that budgerigars remembered the location of the reward well, according to previous study, we considered searching more than 4.5 wells as random searching. One-sample t-tests were conducted on the scores of the budgerigars in the third and fourth phases. We adopted six generalized linear mixed models (GLMMs) to analyze the effects of sex, tarsus length, exploration, and head volume on the cognitive performances in the six tests. We added neophobia as an independent variable in the inhibitory control, associative learning, and reversal learning tasks. To investigate the effects of sex and exploration on the problem-solving attempts, we adopted two GLMMs. Furthermore, we added the time before touching the apparatus as an independent variable in the problem-solving (complex apparatus) task. The ID was used as a random effect in all models, and all data analyses were conducted in R version 4.4.2. [Results] The repeatability of exploratory behavior was significant in exploration tests (R = 0.508, P < 0.001), and the confidence interval was [0.333, 0.651]. The average neophobia of individuals towards the inhibitory control apparatus was 373.3 ± 706.1 s, and that towards the associative-reversal learning apparatus was 141.2 ± 412.7 s. In the inhibitory control task, the average number of successful attempts was 7.42 ± 2.35. We found that a smaller head volume corresponded to a higher score in inhibitory control (Fig. 2a; Table 1), and male budgerigars had higher scores than females (Fig. 2b; Table 1). The scores in the inhibitory control task were not significantly related to neophobia or exploration (Table 1). In the associative learning task, the average number of attempts to meet the criterion was 46.84 ± 31.10. Individuals with smaller head volumes had lower number of attempts (Fig. 2c; Table 1), and male budgerigars had lower scores than females (Fig. 2d; Table 1). The attempts were not significantly related to neophobia, sex, exploration, or tarsus length (Table 1). In the reversal learning task, the average number of attempts to meet the criterion was 60.56 ± 24.07. The attempts were not significantly related to neophobia, sex, exploration, head volume, or tarsus length (Appendix 1). In the spatial memory task, the average number of attempts to find the reward well was 4.04 ± 3.39. No significant associations were found between measured factors and spatial memory scores (Appendix 1). In the problem-solving task (simple apparatus), the problem was solved by problem solvers in 3.58 ± 3.77 h (n = 40), and the non-problem solvers did not solve the problem within 16 h (n = 12). The number of attempts was 15.58 ± 11.54 (n = 52). Among the birds, fast explorers were more likely to open the apparatus (Fig. 3a; Table 2). Females were more likely to open the apparatus than males (Fig. 3b; Table 2). Budgerigars with longer tarsus were more likely to open the apparatus (Table 2). Whether the budgerigar could open the apparatus was not significantly related to the head volume (Table 2). Among the 40 budgerigars that successfully solved the problem, females spent shorter time to open the apparatus (Fig. 3b; Table 2), and the time was not significantly related to exploration, tarsus length, or head volume (Table 2). The number of attempts was not significantly correlated with sex among all budgerigars or only problem solvers (Appendix 2). In the problem-solving task (complex apparatus), the problem was solved by problem solvers in 3.49 ± 3.22 h (n = 30), and the non-problem solvers did not solve the problem within 16 h (n = 22). The number of attempts was 20.35 ± 16.54 (n = 52), and the time before touching the apparatus was 769.8 ± 1 890.4 s. Among the birds, females were more likely to solve the problem than males (Fig. 3c; Table 3). Whether the budgerigar could open the apparatus was not significantly related to exploration, tarsus length, the time before touching the apparatus, or head volume (Table 3). Among the 30 budgerigars that successfully solved the problem, individuals with longer tarsus spent shorter time to open the apparatus, and the time was not significantly related to sex, exploration, the time before touching the apparatus, or head volume (Table 3). Among the budgerigars that successfully solved the problem, females had a higher number of attempts than males (estimate = 14.410, SE = 5.692, df = 26, χ2 = 6.409, P = 0.011; Fig. 3d), while the number of attempts was not significantly correlated with exploratory behavior or the time before touching the apparatus (Appendix 3). Among all budgerigars, the number of attempts did not significantly correlate with exploration, sex, or the time before touching the apparatus (Appendix 3). [Conclusion] The findings indicate that cognition is related to personality, sex, and physical conditions, which enrich the understanding of cognition and its influencing factors. In the future, more in-depth experiments should be conducted, such as additional personality tests to examine their interrelationships and connections to cognitive performance.

Abstract:[Objectives] Understanding seasonal and habitat-related variations in stress hormone levels is essential for assessing wildlife physiological responses and adaptation to environmental changes. The Przewalski’s Gazelle (Procapra przewalskii), a rare and endangered species endemic to China, has long been affected by habitat fragmentation and human activities. It holds significant research value for exploring the physiological response mechanisms of endangered species to environmental stress. This study aims to compare seasonal fluctuations in fecal cortisol levels between wild and semi-captive populations and investigate sex differences in stress responses. [Methods] Fecal samples were collected from wild gazelles in the eastern region of Qinghai Lake and semi-captive individuals at the South Bank Rescue Center across three seasons: summer (June–July), autumn (September–October), and winter (January). Cortisol concentrations were quantified by radioimmunoassay (RIA). Prior to analysis, Shapiro-Wilk tests and Levene’s test were performed to assess data normality and homogeneity of variance. Multivariate analysis of variance (MANOVA) was performed to examine the effects of habitat, season, and sex on cortisol levels, followed by Mann-Whitney U tests for pairwise comparisons. [Results] Cortisol levels varied significantly across seasons (F2, 155 = 48.222, P < 0.001) and between habitats (F1, 155 = 5.244, P = 0.023), with wild individuals exhibiting higher cortisol levels than semi-captive ones, particularly in autumn and winter. Seasonal fluctuations followed a distinct pattern, with peak cortisol levels observed in summer and the lowest levels in winter. A significant interaction between sex and season was detected (F2, 155 = 4.962, P = 0.008). In summer, females exhibited higher cortisol levels than males (U = 25.0, P = 0.013), whereas this trend became opposite in winter (U = 102.0, P = 0.023). The results are illustrated in Figs. 2 and 3. [Conclusion] This study provides the first quantitative comparison of stress hormone levels between wild and semi-captive Przewalski’s Gazelles, revealing distinct seasonal and sex-related variations. Elevated cortisol levels in wild populations during autumn and winter likely reflect heightened environmental stressors, such as food scarcity and harsh climatic conditions. Seasonal peaks in cortisol correspond to key biological events, with higher summer levels in females potentially associated with reproductive demands and heightened vigilance, while increased winter cortisol levels in males may be linked to mating competition. These findings improve our understanding of the physiological adaptation of this endangered species to environmental stresses and offer critical insights for formulating conservation strategies.

Abstract:[Objectives] The introduction of Silver Foxes (Vulpes vulpes) as a natural predator is one of the biological control measures against Plateau Pika (Ochotona curzoniae). Investigating the survival status of artificially released Silver Foxes is crucial for assessing their effectiveness in rodent control. [Methods] This study was conducted in the Plateau Pika distribution areas of Xiahe, Luqu, and Maqu counties in Gannan Prefecture, China. In October 2019 and October 2022, a total of 13 Silver Foxes equipped with GPS+VHF tracking collars were released in the field. The abiotic factors (climatic factors, terrain factors, and distance from water source) and biotic factors [normalized difference vegetation index (NDVI) and human disturbance factors] were obtained from the location data transmitted by the tracking devices. Correlation and multivariate stepwise regression analyses were performed to analyze the survival duration of Silver Foxes and clarify the relationships between their survival duration and ecological factors. ArcGIS 10.2, SPSS 27, Origin 2022, and Excel 2019 were used for data analysis and chart production. [Results] (1) Among the 13 released individuals, five (38.46%), six (46.15%), and two (15.38%) survived less than one month, 2 ~ 3 months, and more than six months, respectively (Table 2). (2) The survival duration was positively correlated with mean annual temperature (r = 0.62, P < 0.05, Fig. 3a) and negatively correlated with elevation (r = -0.62, P < 0.05, Fig. 2a) and humidity (r = -0.70, P < 0.05, Fig. 3b). Although survival duration was negatively correlated with NDVI, distance from water source, distance from residential area, and distance from road, these relationships were not statistically significant (Figs. 4, 5). (3) Multivariate stepwise regression analysis further identified humidity as the key ecological factor, which explained 56.60% of the variation in survival duration (Table 3). [Conclusion] The survival capacity of artificially released Silver Foxes is relatively limited, and under winter (October) release conditions, ambient humidity is the main factor constraining their survival duration.

Abstract:Takydromus albomaculosus, belonging to the family Lacertidae, is currently known to be distributed only in Guangdong, China. From July to September 2024, three suspected specimens of this species were collected from the Guangxi Daguishan Crocodile National Nature Reserve in Hezhou, Guangxi, China. Morphological comparisons and phylogenetic analyses confirmed that these specimens were T. albomaculosus, representing a new distribution record of this species in Guangxi Zhuang Autonomous Region, China. This discovery enhances our understanding of the reptilian species diversity in Guangxi and provides foundational data for studying the geographical distribution and phylogeny of T. albomaculosus.

Abstract:[Objectives] Reproduction is a critical phase in the life history of birds, with the selection of an appropriate nest site being paramount to reproductive success. This selection is influenced by a multitude of environmental factors. Accelerated urbanization leads to habitat fragmentation and compression of avian living spaces, compelling birds to adapt swiftly. The impacts of urbanization on birds are multifaceted, resulting in differences in nest site selection and other aspects compared with their rural counterparts. Therefore, investigating the nest site selection of Chinese Blackbirds (Turdus mandarinus) in urban and rural settings is of great importance and necessity, contributing to our understanding of how birds adapt to urbanized environments. [Methods] From May to August 2024 and April to May 2025, we conducted systematic surveys for Chinese Blackbird nests in Huangpi District, Wuhan City, Hubei Province. Nests were surveyed bi-weekly. Upon nest discovery, the internal conditions were recorded, and each nest was sequentially numbered and located in the order of discovery. Following the conclusion of the breeding season, nest characteristic parameters, including inner diameter, outer diameter, cup depth, and nest depth, were measured via a fine measuring tape. Nest site parameters were measured via a measuring tape, while distances beyond the range of the tape were measured via ArcGIS software. A total of 14 nest site parameters related to the reproduction of Chinese Blackbirds were recorded. [Results] During the study period, we recorded the nest characteristic parameters of 62 Chinese Blackbird nests (21 urban nests and 41 rural nests) and 14 nest site parameters of 128 Chinese Blackbird nests (49 urban and 79 rural nests). There were no significant differences in the nest characteristic parameters between urban and rural nests. The distances from nests to trees and farmlands were significantly shorter for urban nests than for their rural counterparts, while tree height, diameter at breast height, and coverage above the nest were significantly greater for urban nests than for rural nests. Urban Chinese Blackbirds showed a preference for nesting in Camphor Trees (Cinnamomum camphora), whereas rural Chinese Blackbirds nested in a wider variety of tree species. Urban Chinese Blackbirds preferred to nest in taller, more robust trees with better concealment (Table 3). [Conclusion] This study demonstrates that predator avoidance is the primary factor influencing nest site selection for Chinese Blackbirds. Urban Chinese Blackbirds exhibit a preference for taller and more concealed tree canopies to evade predators, particularly feral cats. Foraging considerations also play a crucial role. Rural Chinese Blackbirds tend to nest near farmlands and woodlands, while their urban counterparts rely on green spaces such as parks and urban forests. Urbanization influences nest preferences, leading to a propensity for specific tree species and taller trees. The adaptability of Chinese Blackbirds to urban environments is evident, as exemplified by instances of nesting on utility poles. Future research will delve into the adaptive changes of Chinese Blackbirds across varying degrees of urbanization, thereby contributing theoretical insights to support urban ecological conservation and avian research.

Abstract:[Objectives] Bird songs serve the functions of territory defense and mate attraction. Many bird species exhibit high singing activity both in the early morning and at dusk. However, most studies on bird songs typically focus on morning vocalizations rather than those at dusk. Since bird song characteristics are typically influenced by a range of internal and external factors, the different environmental conditions between morning and dusk may lead to variations in songs within the same species, such as differences in acoustic parameters or qualitative characteristics. However, such differences have only been verified in a limited number of species, and whether this phenomenon exists in most bird species with bimodal singing patterns remains unclear. In this study, we investigated the songs of Light-vented Bulbuls (Pycnonotus sinensis), a common small urban songbird with prominent singing behaviors during both morning and dusk, aiming to compare the song differences between these two periods and analyze the potential underlying causes. [Methods] Recordings of Light-vented Bulbul songs were collected between mid-April and mid-May 2019. Sampling was conducted on clear days during two specific time periods: morning (6:00 ~ 9:00) and dusk (16:00 ~ 19:00). The study was carried out in Hongshan District, Wuhan, where songs were recorded from 15 different territories, each separated by at least 1 km (Fig. 1). A total of 302 songs were recorded during the morning, while 268 were recorded at dusk. For each male’s song, the following parameters were measured and calculated: 1) frequency parameters: maximum frequency, minimum frequency, frequency range, and peak frequency; 2) temporal parameters: song duration and between-song interval; 3) energy parameters: aggregate entropy and average entropy; 4) qualitative characteristics: number of syllables per song and number of syllable types per song. Additionally, we examined syllable type occurrence rate, song type occurrence rate, song type variants occurrence rate, and song type variability. Spectrograms for a song type example and its song type variants are shown in Fig. 2. To examine whether there were differences in the song characteristics of Light-vented Bulbuls between morning and dusk, we calculated the mean values and coefficients of variation (CVs) for each acoustic parameter of each individual. A repeated measures multivariate analysis of variance (repeated measures MANOVA) was conducted to compare the overall song parameters of Light-vented Bulbuls between morning and dusk. The syllable type occurrence rate, song type occurrence rate, song type variants occurrence rate, and song type variability were compared between morning and dusk by the Wilcoxon signed-rank test. All statistical analyses were performed in IBM SPSS Statistics for Windows, version 22.0 (IBM Corp., Armonk, N.Y., USA). [Results] There were no significant overall differences in song characteristics between the two periods (repeated measures MANOVA, Pillai’s Trace, F9,6 = 1.931, P > 0.05). Similarly, no significant overall differences were found in the CVs of these parameters between morning and dusk (Pillai’s Trace, F10,5 = 1.610, P > 0.05). Song parameters and their CVs between morning and dusk are presented in Tables 1 and 2. Each Light-vented Bulbul produced an average of 5.0 ± 1.4 syllable types, 1.3 ± 0.5 song types, and 3.2 ± 1.4 variants per song type during morning singing. During dusk, the averages were 5.1 ± 1.1 syllable types, 1.1 ± 0.4 song types, and 3.2 ± 2.1 variants per song type. At the same recording sites, individuals used the same song types in both morning and dusk periods (Fig. 3). There were no significant differences between morning and dusk in syllable type occurrence rate (Wilcoxon signed rank test, Z14 = -0.738, P = 0.480), song type occurrence rate (Z14 = -0.057, P = 0.978), song type variants occurrence rate (Z14 = -0.966, P = 0.359), or song type variability (Z14 = -0.255, P = 0.832). [Conclusion] There are no significant differences in the aforementioned acoustic parameters of Light-vented Bulbul’s songs in the study area, suggesting that the characteristics, stability, and overall qualitative characteristics of the birds’ songs remain consistent between the morning and dusk periods. It is hypothesized that the diurnal variations in environmental factors within the same habitat is insufficient to cause significant changes in the song characteristics of Light-vented Bulbuls, and social factors may potentially mask the effects of these environmental changes. Therefore, it can be concluded that there are no significant difference between the morning and dusk songs of Light-vented Bulbuls in the study region. This study contributes to filling the gap in the research on the vocal behavior of Light-vented Bulbuls and provides new insights into the dynamic patterns of bird vocalizations.

Abstract:To understand the current status of Chiroptera species diversity in the northwest and southwest regions of China, we conducted a field survey in Qinghai in July 2023. Six bat specimens (3♀ 3♂) were collected using harp nets and mist nets in Xunhua Salar Autonomous County, Haidong City, Qinghai Province, China. Morphological and molecular systematics methods are used for species identification. These bats possesses a medium body size, with a forearm length of 51.45 ± 2.18 mm (49.03﹣54.29 mm, n = 6). The ear measures 16.96 ± 1.52 mm (15.30﹣18.86 mm, n = 6) and does not extend beyond the rostrum tip when folded forward. The tragus is short at 7.48 ± 1.07 mm (5.83﹣8.65 mm, n = 6), approximately half the ear length. The skull snout is low and upturned with a low and flat forehead. The greatest skull length measures 17.99 ± 0.13 mm (17.85﹣18.17 mm, n = 4), with a braincase height of 7.00 ± 0.27 mm (6.60﹣7.22 mm, n = 4). Upper gear row length 6.84 ± 0.25 mm (6.52﹣7.12 mm, n = 4) (Appendix 1)The second upper and lower premolars are extremely small and located in the dentition. The dorsal pelage exhibits brown coloration with blackish-gray tips, while the ventral pelage displays black hairs tipped with grayish-white.(Fig 1) These characteristics demonstrate congruence with the external morphology and cranial features of Myotis pequinius. The Bayesian phylogenetic analysis results showed that the Qinghai sample was clustered with the M. pequinius from other regions. The genetic distance between the Qinghai specimen and theM. pequinius distributed in Shaanxi is the closest(Appendix 2). The species were identified as M. pequinius, a new record in Qinghai Province. The research results enriched the species diversity and distribution data of the Chiroptera in China, and providing basic information for the phylogenetic geography research of the M. pequinius.

Abstract:[Objectives] There are three recognized species within the genus Filogranella across the world, and most of them distribute in regions including the Red Sea, the Caribbean Sea, and costal region along Indonesia, Philippines, and Malaysia. This study reported the first distribution record of a reef-building tube worm species from the genus Filogranella in China, which was collected from the lagoon of the Meiji Reef in the South China Sea on April 25, 2024. [Methods] Optical microscopy and scanning electron microscopy were used to identify the morphological characteristics of this species. The mitochondrial 18S rRNA gene fragment was amplified and sequenced to reconstruct the phylogenetic relationships of the species in the family Serpulidae. [Results] The worms inhabit in white calcareous tubes and are composed of four parts: branchial crown, thoracic region, abdominal region, and posterior region. A light-yellow funnel is shown in some individuals occasionally; the worms usually demonstrate thoracic membranes which extend to the middle of the thoracic region; the pinnule is red in color at the root, and form a circular structure when stretch out (Fig. 1). Thoracic region of the worms has 12 or more thoracic chaetigers. The collar chaetiger demonstrates smooth capillary collar chaetaes and geniculate chaetaes, whereas the other thoracic chaetigers show much more diverse structures of chaetaes, including capillary collar chaetaes, smooth capillary collar chaetaes, coarse-toothed collar chaetaes, apomatus chaetaes, and sickle-chaetaes. The abdominal uncini is rasp-shaped with 3 to 7 teeth in transverse rows; posterior region encompasses a slit-like anus (Figs. 2, 3). The Maximal likelihood tree based on the 18S RNA sequence fragment shows that the sample in this study clusters with Filogranella elatensis. Sequence alignment between F. elatensis and our sample shows a comparable fragment with length of 438 bp, and similarity of 99.09% (Table 1, Fig. 4). [Conclusion] Combining the morphological taxonomic characteristics and molecular phylogenetic evidence, this species is identified as F. elatensis. The new distribution record of F. elatensis in this study enriches the marine species database of China.

Abstract:[Objectives] Sturgeons are evolutionarily significant and economically important fish in China, particularly valued for caviar production. Due to the lack of distinct secondary sexual characteristics between sexes, sex identification of farmed sturgeons remains challenging with conventional methods. This study aims to develop a minimally invasive DNA-based molecular marker for accurate early sex identification in farmed sturgeons, providing a solution that is minimally invasive, rapid, accurate, species-versatile, and beneficial for both sturgeon aquaculture and conservation efforts. [Methods] A total of 155 sturgeon samples were collected from Zhejiang and Heilongjiang provinces. The 110 samples from Zhejiang, with known sex information, served as standard controls, while the 45 samples from Heilongjiang were juvenile sturgeons of unknown sex. DNA was extracted from the dorsal fin tissue via a commercial kit. An ultra-trace nucleic acid protein analyzer was used to measure the DNA purity and concentration. Specific primers (Asc418F/Asc418R) were designed by Primer Premier 5.0 software based on the genome resequencing data from 3-year-old Acipenser schrenckii. Temperature gradient PCR (45 ~ 62 ℃) was performed to optimize the annealing temperature, and the primer sensitivity was verified via a 10-fold serial dilution of plasmid DNA. [Results] The female-specific 418-bp DNA fragment (designated ZXJAscF418) was successfully amplified only in female sturgeon samples. The results demonstrated that the primers for this DNA marker exhibited excellent amplification specificity, with an effective annealing temperature range of 45 ~ 59 ℃ (Fig. 1). The optimal annealing temperature was 56 ℃, as band intensity decreased above 58 ℃ and became undetectable at 62 ℃. The primers exhibited high sensitivity, reliably detecting DNA concentrations as low as 6.55 × 10-6 mg/L, with complete loss of visible bands at a 10-8 dilution (Fig. 2). Application of this molecular marker achieved 100% accuracy in sex identification for four sturgeon species (A. schrenckii, Huso dauricus, H. dauricus♀ × A. schrenckii♂ F1, and A. gueldenstaedtii) from Zhejiang (Fig. 3). For the juvenile sturgeons of unknown sexes from Heilongjiang, the method predicted a female-to-male ratio of 1.25:1 (Fig. 4). [Conclusion] This study developed a DNA-based molecular marker assay for sex identification in farmed sturgeons. The assay demonstrated minimally invasive sampling, operational simplicity, high rapidity, and high accuracy across multiple sturgeon species. This approach enables reliable early sex identification, with significant implications for sturgeon health management, cost saving, and conservation efforts. It may serve as a critical tool for restoring endangered sturgeon populations through artificial breeding.

Abstract:[Objectives] Using the satellite collar tracking data of six Mongolian wild asses (Equus hemionus) in 2021 and 2024, we delineated the seasonal activity range and identified their core habitats. [Methods] We analyzed the activity areas and spatial distribution patterns of Mongolian wild asses in the warm season (April to October) and cold season (November to the next March) by integrating GIS location data with Maximum Entropy (MaxEnt) modeling. Species occurrence records and environmental variables were processed in MaxEnt, with output habitat suitability values classified into three tiers via the Natural Breaks method: rare activity area (0 ~ 0.3), general activity area (0.3 ~ 0.7), and concentrated activity area (0.7 ~ 1.0). Spatially intersecting high-activity areas were delineated as core habitats across seasons. [Results] The model results showed that in 2024, the concentrated activity area, general activity area, and rare activity area of Mongolian wild asses during the warm season covered 4 739.08 km2, 3 466.26 km2, and 6 514.16 km2, respectively (Fig. 2), while the corresponding areas in the cold season were 5 938.88 km2, 4 512.41 km2, and 4 268.20 km2 (Fig. 3). Compared with that in 2021, the concentrated activity area in 2024 increased by 382.67 km2 in the warm season but decreased by 1 826.01 km2 in the cold season. The activity range in the cold season was significantly larger than that in the warm season, with distinct spatial differences in core habitats between the two seasons. During the warm season, Mongolian wild asses primarily aggregated near transportation routes in the central part of the reserve, whereas in the cold season, their distribution expanded eastward toward the Kalamaili Mountains and Sanbastao, while also dispersing northward to Xibaroy and westward into desert regions. Core habitats accounted for 32.2% and 40.4% of the total activity ranges in the warm and cold seasons, respectively (Fig. 4). [Conclusion] The activity areas exhibited a certain degree of fragmentation, with transitional zones of rare activity between some concentrated areas. The ecological spatial distribution and influencing environmental factors varied between warm and cold seasons, with transportation infrastructure, elevation, water source distribution, and vegetation type (Table 2) being key determinants of habitat selection. These findings provide a methodological framework for predicting the future potential habitats of Mongolian wild asses.