Climate change is altering not only average temperatures but also the frequency and intensity of climatic extremes, including late-spring frost events following unusually warm periods. These abrupt temperature fluctuations can disrupt trophic interactions by damaging newly emerged vegetation and reducing food availability for insectivorous birds during reproduction. However, their effects on maternal reproductive investment remain poorly understood. We used a natural experiment in a montane population of Pied Flycatchers (Ficedula hypoleuca) breeding in central Spain to evaluate whether an exceptional and pronounced spring frost in 2024 influenced reproductive decisions. We compared laying date, egg volume, and hatching success across three consecutive breeding seasons (2023–2025), combining reproductive monitoring with temperature records and satellite-derived vegetation activity (NDVI). Vegetation activity was lower during the frost year, coinciding with severe canopy defoliation following an abrupt temperature decline after an unusually warm early spring. Females laid significantly smaller eggs during the frost year than in the preceding and following breeding seasons, whereas laying date and hatching success showed comparatively limited interannual differences. These findings are consistent with the hypothesis that females reduced reproductive investment when energetically constrained while maintaining overall reproductive performance. Low within-female repeatability of egg volume suggests high phenotypic plasticity in response to environmental conditions. Our study suggests that short-lived climatic extremes may influence reproductive allocation even when downstream reproductive success remains relatively unaffected. These findings highlight the importance of considering extreme weather events, alongside long-term warming trends, when evaluating avian responses to climate change.
Aquatic macroinvertebrates serve as vital food sources in freshwater ecosystems. Species identification remains challenging due to morphological similarities, developmental-stage variation, and limited taxonomic expertise. This study assessed the challenges associated with DNA barcoding for species identification of aquatic macroinvertebrates and its application in supporting biological water quality assessment in Kwan Phayao, Thailand. A total of 203 representative samples were analyzed. Morphological identification classified the samples into 13 orders, 7 classes, and 3 phyla, whereas mitochondrial cytochrome c oxidase subunit I (COI) sequences were compared with the reference databases and integrated with phylogenetic analysis and Automatic Barcode Gap Discovery (ABGD), revealing 86 distinct taxa across 37 genera and 29 families. Nonetheless, only 25.62
The dwarf crocodile Osteolaemus tetraspis is globally listed as Vulnerable, yet remains heavily harvested across West and Central Africa particularly in the Niger Delta, Nigeria. This study assessed the spatio-temporal variation in the relative abundance of O. tetraspis across three major bushmeat markets: Uwa (Edo State), Edumanon (Bayelsa State), and Ogbe-Ijaw (Delta State) to inform conservation and management interventions. Bushmeat market surveys were conducted fortnightly between October 2021 and April 2022. All crocodiles encountered were counted and measured across three size classes (60, 90, and ≥ 120 cm). A negative-binomial generalized linear mixed model (GLMM) was fitted to monthly counts of Osteolaemus tetraspis to account for overdispersion in the abundance data. Temporal (Month) and spatial (Market location) effects, as well as their interaction, were treated as fixed effects. A total of 158 O. tetraspis individuals were recorded, dominated by medium-sized (39.24
We investigated the migration dynamics of two Atlantic salmon (Salmo salar) smolt origin groups (hatchery, n = 374; natural, n = 231) in the Penobscot River Estuary and Bay, Maine, U.S.A., during the springs of 2010–2012. Smolts were acoustic-tagged and tracked for approximately 100 km to evaluate differences in movement rate, migration duration, path choice, and survival. While the behavioral differences between origin groups were not consistent, differences in survival were evident. Using a Cormack-Jolly-Seber mark-recapture model, we found that rearing origin and river discharge were the primary factors influencing smolt survival. Survival decreased with increasing river discharge across the observed range. Hatchery smolts (cumulative survival: 0.40–0.69) presented higher survival rates than their natural counterparts did (0.32–0.64), a finding that is inconsistent with much of the literature on hatchery versus river-reared fish. We hypothesize that the collection method for natural smolts at a dam bypass facility, which involves novel handling and dam interaction, may have contributed to their lower survival, potentially masking any inherent advantage over hatchery smolts. These findings underscore the importance of minimizing dam-related stressors and informing management actions aimed at improving the survival of outgoing smolt cohorts. Improved dam passage is critical for increasing overall restoration efforts.
To predict how movement strategies shape fitness in a changing world, we must build mechanistic models of species’ ranges and range shifts that align environmental data with the scales of individual perception and decision-making and jointly model biological processes from the individual to the population scale.
Understanding how closely related species coexist in shared environments provides key insights into their ecological differentiation and adaptive potential. In Central Europe, the European hedgehog (Erinaceus europaeus, EE) and the Northern white-breasted hedgehog (E. roumanicus, ER) meet in an extensive contact zone that includes large urban areas. Using a seven-year dataset from the Prague Wildlife Rehabilitation Centre, we compared the two species in terms of spatial distribution, seasonal activity, and rehabilitation outcomes to assess their ecological patterns in an urban environment. The species exhibited distinct spatiotemporal patterns. While the EE was mainly confined to the southwestern part of the city, the ER dominated in the east, suggesting a dispersal barrier associated with the Vltava River. The EE showed a later and narrower reproductive period, consistent with one annual litter, whereas the ER showed earlier juvenile admissions and a pattern consistent with two litters per year. The EE further showed increased late-season admissions and lower release rates, while the ER had higher rehabilitation success. These differences suggest an ecological asymmetry between the EE and the ER within the Prague contact zone, with the ER showing signs of greater tolerance of urban conditions and the EE appearing more constrained under local urban conditions. Our findings demonstrate that wildlife rehabilitation center data can serve as an important source of comparative ecological information and help reveal how closely related species respond to human-dominated environments when interpreted with caution.
Background The rapid expansion of environmental DNA (eDNA)-based biodiversity monitoring has heightened the need for accurate and well-curated taxonomic reference databases. Although mitochondrial cytochrome oxidase I (COI) is widely used, the mitochondrial 12S ribosomal RNA gene (12S rRNA) has increasingly demonstrated strong taxonomic assignment success in chondrichthyan metabarcoding applications. The South African coastline supports one of the most diverse chondrichthyan faunas globally. However, as in many regions, coverage of 12S rRNA reference databases has remained limited. Well-represented reference libraries are critical for improving the accuracy of eDNA-based species detection. Here, we aimed to expand the regional 12S rRNA reference database for South African chondrichthyans, thereby supporting both local and global eDNA applications for widely distributed species.Results A total of 36 chondrichthyan species, represented by 69 individuals, were sequenced to expand the 12S rRNA reference library for sharks, rays and chimaeras from South Africa's Indian and Atlantic Ocean coastlines. A newly developed primer set (V05F_898E / teleoR_Elas), designed to overlap with the commonly used Elas02 region, achieved consistent amplification across diverse lineages. The new data increased regional reference coverage from 50.3% to 69.1% and added 18 species globally. Sequence authenticity was confirmed through comparison with GenBank, and Bayesian phylogenetic analyses showed that 97.2% of sequences clustered within their expected family-level lineages, although some uncertainties remained in groups with low mitochondrial divergence or complex taxonomic histories. Percent identity analyses revealed high intraspecific similarity and clear interspecific separation across taxa. However, comparative in silico analyses of the shorter Elas02 fragment demonstrated reduced phylogenetic resolution and less consistent clustering among closely related taxa. While the Elas02 region is suitable for accurate amplicon sequence variant (ASV) matching in eDNA metabarcoding, the longer 12S rRNA fragment generated here provides improved phylogenetic resolution and may aid in the identification of unknown or ambiguous ASVs.Conclusion The expanded 12S rRNA reference library and associated phylogenetic analyses expanded genetic resources for South African chondrichthyans and support global applications. The newly developed marker can be incorporated in future eDNA studies dealing with elasmobranchs, since it can have the added benefit of providing more phylogenetic resolution than the short Elas02 fragment.
An Indo-Pacific bottlenose dolphin (Tursiops aduncus) in the coastal waters of Jeju Island, Republic of Korea, exhibited an oral mass and mandibular deformity over a documented 6-year period, including 3 years of intensive longitudinal monitoring by our research team. A multidisciplinary approach combining imaging, pathology, microbiology, and omics analyses was used to assess the dolphin. Post-mortem computed tomography confirmed a mandibular fracture at the oral mass site. Histopathological examination of the oral mass revealed prominent fibroblast proliferation and collagen deposition. Fibropapillomas and desmoid tumors were excluded based on viral detection assays and β-catenin accumulation analysis, supporting a diagnosis of trauma-induced fibroma. Transcriptomic analysis of the tumor tissues identified highly expressed genes associated with extracellular matrix remodeling, myofibroblast activation, and epithelial differentiation, supporting a reactive fibrotic rather than malignant phenotype. Gross necropsy revealed multiple suppurative pulmonary lesions, abundant foamy fluid within the respiratory tract, and diatoms within the pulmonary tissue. Metagenomic sequencing revealed a polymicrobial infection, with Parvimonas micra as the predominant organism. Collectively, these findings are most consistent with aspiration pneumonia, with severe secondary pulmonary infection considered a major contributor to death. In addition, analysis of halogenated organic contaminants revealed accumulation levels consistent with those typically observed in aged individuals, and no evidence was identified indicating a direct causal role in the terminal disease process. To the best of our knowledge, this is the first study to characterize the pathological features and proposed pathogenic mechanism of traumatic fibroma in a marine mammal, and the first confirmed case of pulmonary abscessation associated with Parvimonas micra infection in this taxonomic group. Overall, these findings provide valuable baseline data for the health monitoring and conservation of marine mammal populations.
The Eurasian otter (Lutra lutra Linnaeus, 1758) is an endangered species in Bulgaria and is protected under national legislation. Under harsh environmental conditions, as well as the increasing anthropogenic pressure, knowledge about this species is fundamental for conservation planning. The otter occupies a broad range of freshwater habitats, and the species has also been recorded along the Bulgarian Black Sea coast. The contribution of both components of this complex habitat—freshwater and marine environments—to the otter’s diet has been demonstrated. The study confirmed that the otter is primarily piscivorous, consuming predominantly freshwater fish during the cold season, and - marine fish during the warm season. Non-marine arthropods were found as an essential secondary food for the otter with a relative frequency of occurrence (RFO) of 22.2
Ovarian assessment and monitoring are crucial for reproductive management and breeding programs in animal production. Currently, there is a lack of quantitative and non-invasive methods for ovarian assessment and monitoring in crab species. In the present study, magnetic resonance imaging (MRI) was utilized to characterize the ovarian morphology of mud crabs during vitellogenesis. The ovaries exhibited low signal intensity in T2-weighted magnetic resonance images and displayed intermediate signal intensity in T1-weighted magnetic resonance images. The ovarian shape varied topologically among different cross-sectional images and changed considerably across different developmental stages. From the early to late stages, the ovaries increased in size, as determined by MRI measurements at the eyes in the sagittal plane and at the commissure of the ovaries, heart, and flank in the transverse plane, which were positively correlated with values of the gonadosomatic index (GSI). The GSI was well-plotted against MRI measurements using two-variable linear regression. Among them, five regression models appeared promising for estimating GSI values in ovarian assessment of live mud crabs. The growth of the ovaries was documented in three mud crabs through repeated MRI scans, suggesting that this non-invasive method could be employed for longitudinal monitoring. Our findings demonstrate the application of MRI for ovarian assessment and monitoring in mud crabs, providing new insights into assisted reproductive technology in decapods.
Tracking small-bodied animals in estuarine environments entails significant technological and analytical challenges. Diamond-backed terrapins are small (max 1.4 kg) turtles that inhabit salt marshes of the eastern U.S. and the Gulf of Mexico. Terrapin movements have been studied with VHF radio telemetry, acoustic telemetry, and mark and recapture methods, which have indicated maximum straight-line movement distances < 10 km and mean home ranges < 1 km2. We deployed 21 Argos satellite tags on adult female terrapins at two sites on Long Island, New York to better understand the spatial ecology of this imperiled species, and to test newly available tracking technology. We processed the location data three ways: (1) we used a location data filter to remove unlikely terrestrial and oceanic locations and applied a state-space model to account for Argos location errors, (2) we applied the state-space model to unfiltered data to determine the effects of not removing unlikely locations, and (3) we used only the highest quality location class 3 (LC 3) locations. We used the data resulting from each of these approaches to calculate four different movement metrics: summer home range size (95
The pear psyllid (Cacopsylla pyri), the main vector of ‘Candidatus Phytoplasma pyri’, relies on substrate-borne vibrational signals for mate recognition and duet coordination. As pathogens can alter insect communication, we examined whether phytoplasma infection alters key parameters of male and female mating signals. We used laser vibrometry on a standardised artificial substrate, as well as playbacks, to examine this. We detected sex-specific differences in individual signal parameters. In males, infection significantly reduced the amplitude of chirps, whereas uninfected males showed a markedly higher number of interruptions within their trill units. Infected females produced longer inter-chirp intervals and showed higher dominant spectral components than uninfected females. However, fundamental frequency remained stable across treatments, suggesting that differences in dominant frequency reflect shifts in spectral energy among harmonics rather than changes in the primary oscillation frequency. These infection-induced changes may reflect physiological constraints affecting vibrational mechanics. These findings suggest that infection-related differences in dominant frequency reflect changes in the distribution of spectral energy among harmonics rather than a change in the fundamental frequency. Despite these differences at the individual level, the preliminary results of duet communication between males and females did not differ significantly across the various infection treatments. This suggests that the basic coordination in the duet may not be significantly impaired under laboratory conditions; this should be investigated more closely in a specially designed experiment.
Brood parasitism is a significant reproductive strategy among birds. Both the Scaly-sided Merganser (Mergus squamatus) and the Mandarin Duck (Aix galericulata) are tree-cavity-nesting waterbirds with overlapping ecological niches. Although field observations have previously suggested that Mandarin Ducks may parasitize the nests of Scaly-sided Mergansers, direct evidence of successful hatching of parasitic eggs has been lacking. During the 2024 breeding season in the Manjiang region of Changbai Mountain, Jilin Province, field monitoring documented a case where a Mandarin Duck laid an egg in an artificial nest box intended for Scaly-sided Mergansers. Using eggshell membranes collected after hatching, we performed species identification for all ducklings based on the mitochondrial 12S rRNA gene as a genetic marker. Combined with morphological observations, we confirmed that one duckling was a Mandarin Duck, while the rest were Scaly-sided Mergansers. Analyses of the mitochondrial D-loop region and eight microsatellite loci indicated that all Scaly-sided Merganser ducklings were full-sibling offspring from the same parental pair. This supports the genetic monogamy in this nest and the absence of intraspecific brood parasitism in this instance. Our study provides molecular-level evidence for a case of successful interspecific brood parasitism by a Mandarin Duck on a Scaly-sided Merganser, enriching our understanding of interspecific interactions among tree-cavity-nesting birds. The findings also offer insights for the conservation of endangered species like the Scaly-sided Merganser. Furthermore, we identified a sequence discrepancy in the Scaly-sided Merganser’s 12S rRNA compared to existing reference sequences, suggesting a need for re-sequencing its mitochondrial genome.
Seed dispersal by primates is a key ecological process, yet research remains comparatively limited in semi-arid savannas. This study investigates the seasonal variation in scat-derived seed deposition and emergence patterns of chacma baboons (Papio ursinus) and their potential role as seed dispersers in Suikerbosrand Nature Reserve, South Africa. Across wet and dry seasons, 240 scats (120 per season) were collected over a 12-month period (May 2012-April 2013). A total of 23,132 seeds, representing 22 plant seed taxa, were recovered from faecal samples. Seed count per scat and taxon representation were higher in the dry season, indicating seasonal differences in ingested resources. Fruits dominated the diet in both seasons, while leaves, grasses, pods and invertebrates contributed more in the wet season. Greenhouse trials recorded seedling emergence from seven taxa in the dry season and five in the wet season. Emergence was dominated by herbaceous forbs, particularly Oxalis corniculata and Chamaesyce prostrata. These results indicate potential for emergence rather than direct germination success or gut-passage effects. By linking seed deposition and emergence, this study provides a process-based assessment of baboon-mediated seed dispersal. Results are interpreted as patterns of seed deposition rather than resource selection. These findings highlight baboons as ecologically relevant seed dispersers and support their role in savanna regeneration processes.
Abstract Background Resource scarcity poses a real challenge to living organisms. The present study aimed to understand the implications of water and food lack on some biochemical markers. The study also aimed to investigate the expression of Hsp70 gene under the same stress conditions. The Hsp70 gene maintains cellular proteostasis. It is unique in its high sensitivity and rapid response to various stress factors compared to other Hsps. Methods Brood frames of Carniolan hybrid bees were incubated at 30 °C and 70% RH. Emerged bees were placed in plastic cages (30 individuals per cage) and received daily diets of pollen-sugar pastes and sugar solutions. After nine days, bees were independently subjected to dehydration and starvation experiments for 24 h. One group was deprived of only sugar solutions (Dehydrated DH), another group was denied both sugar solutions and pollen pastes, receiving only tap water (Starved ST), while a third group continued without water or food deprivation (Control C). Bee samples were collected at 12-hour intervals in each experiment for subsequent investigations. Biochemical measurements were performed on total protein, total antioxidant capacity, peroxidase, catalase, glutathione S-transferase, and acid phosphatase. Gene expression of Hsp70 gene was under observation. Bee weights were also considered. Results Both dehydrated and starved bees showed notable changes in their examined biomarkers. Starvation had a more pronounced and rapid biochemical effect. The decreases in Hsp70 mRNA levels following water or food deprivation were surprising to us and reflect the severity of these two stressors. Other differences were also recorded in the weights of dehydrated and starved bees. Conclusions This study reveals honeybees’ extreme sensitivity to nutritional stress and warns against depriving them of water or food for even a few hours.
Background Accurate age determination is crucial for interpreting the behavior and ecology of raccoon dogs; however, age estimation is often overlooked due to the absence of practical, non-invasive methods or criteria. Existing approaches to age estimation tend to be overly invasive or challenging to implement in field settings, thereby limiting their utility. Results In this study, we analyzed external morphological traits of 37 raccoon dogs, whose age was verified via radiographic analysis of growth plate closure. We characterized morphological differences between adults and juveniles and developed discriminant functions to estimate the age of individuals of undetermined age. In males, adults exhibited significantly larger body weight, body length, tail length, hind foot length, ear length, head length, and neck circumference than juveniles. In females, all measured traits, except for head length, were larger in adults than in juveniles. The discriminant functions based on external morphology successfully classified adults and juveniles with 100% accuracy for both males and females. Multiple discriminant functions combining three morphological variables were generated for each sex, with body length identified as the most important predictor for age estimation in raccoon dogs. Conclusions To the best of our knowledge, this is the first study to present sex-specific, morphometry-based discriminant functions for age estimation in raccoon dogs. With perfect classification accuracy, these functions offer a reliable tool for age estimation. The non-invasive and field-applicable nature of this method offers distinct advantages regarding animal welfare and research practicality.This approach aligns with societal demands for integrating research ethics and animal welfare by minimizing the burden on study animals, thereby enabling more precise and long-term ecological studies.
The marshlands provide water resources and support economic, ecological, and human well-being. However, less is known about the biodiversity of insects, particularly butterflies in marshlands of Rwanda. This study was interested with the assessment of species richness and species diversity of butterflies from a high altitude Rugezi marshland. Data were collected twice in 2023 during the dry (June-July) and the rainy (November-December) seasons. The northeast, central and northwest regions of the marshland were demarcated using published geodata and shapefiles of Rugezi, while the opportunistic sampling was used to select the sites with high probability to find butterflies. Within each site, butterflies were systematically sampled using fruit-baited traps made of banana and pineapple and hand sweep netting. Three traps were placed at each sampling point across a transect of 500 m, where 100 m were maintained between two traps. We left traps in the field and collected them after 24 h. Additionally, specimens were collected using the hand sweep net at each sampling point. The collected specimens were stored in glassine envelopes, brought to the entomology laboratory, and identified to family, genus, and species levels using dichotomous keys. The results revealed a total of 75 species classified into 4 families. The Nymphalidae family had more species than Pieridae, Lycaenidae, and Hesperiidae families during both dry and rainy seasons. Further, more species were sampled in the dry season (47 species) compared to the rainy season (28 species). Of these, 19 species occurred in both dry and rainy seasons. Twenty-eight were only found during the dry season and 9 were only found during the rainy season. We recommend continuous studies in Rugezi and other marshlands to enrich the findings of this study.
Human carnivore conflict is a global issue for conservationists, especially in protected areas such as national parks. Research on human carnivore conflict around the Borena Saynt Worehimenu National Park has been conducted with the aim of assessing the conflict between communities and carnivores. A cross-sectional study design was used to investigate human carnivore conflict in the community of the study area. Among the six bordering woreda (District), four were selected purposively for the study. From each woreda, the village, which is the immediate boundary to the park, was included. Both open- and close-ended questionnaires were administered to 573 randomly selected respondents. A total of six carnivorous species and one opportunistic omnivorous species were reported as predators of domestic animals, causing conflict. Pantera pardus and Crocuta crocuta are the most reported carnivores, with contributions of 46.9% and 26.5%, respectively, to the conflict. Together, sheep and goats are the most common domestic prey, accounting for approximately 71.6% of the prey species. The majority of predation occurs during the day, when domestic animals graze in the communal land. A total of 45.7% of the respondents reported that the degree of conflict has increased in the last three years. Poisoning the remaining parts (43.6%) is the most common response of farmers, while their domestic animals are killed by carnivores, as a revenge followed by chasing (28.8%) and then direct killing (18.8%) as revenge. The total economic cost of carnivore depredation was substantial 22,968,500 ETB (166438 USD). Farmers use guarding and physical barrier techniques, to protect their domestic herd from predators. The respondents believed that effective government intervention should focus on providing alternative livelihoods and compensation for losses of livestock and property. The conflict was attributed to overgrazing, agricultural expansion, and a lack of compensation. The establishment of livestock insurance programs; community-based conservation and benefit sharing; the creation of alternative livelihoods; and education and implementation of regulations are essential measures for reducing and managing conflicts.
The Spanish Late Miocene locality of Batallones-1 (Madrid, Spain) has yielded a very rich sample of large carnivorans, including hyaenids, mustelids, amphicyonids, ailurids, felines, and two species of sabre-toothed felids that represent the first radiation event of the subfamily Machairodontinae: Machairodus aphanistus and Promegantereon ogygia. The former was the size of a tiger and the top predator of the Batallones-1 community, whereas the latter was a much smaller animal, its body weight being similar to that of an extant puma. In the present paper, we study the functional anatomy of the hindlimb of P. ogygia compared to that of extant felines and pantherines of similar size. Our observations reveal that the hindlimb of this early sabre-toothed felid, unlike the relatively derived forelimb, show several primitive features also observed in the earliest felid, Proailurus lemanensis, thus highlighting the mosaic evolution of machairodontine morphology in this Late Miocene sabre-toothed felid.
