Communal laying is the behaviour of females laying eggs together with those of other females of the same species and/or with eggs of other species. Homonota aff. darwinii is a recently discovered species that has not yet been formally described. A previous study suggested that this new species could be a communal laying species. The aim of this study is to confirm communal laying of eggs in nests by H. aff. darwinii. These new findings confirm previous observations and expand knowledge of other aspects of oviposition by H. aff. darwinii in the Central Andes region of Argentina.
Parental care is widespread, but exclusive paternal care is rare in the animal kingdom. To understand the evolution of paternal care, it is important to evaluate the costs and benefits of this behaviour. In the family Belostomatidae (Hemiptera), males care for their eggs until they hatch. In this family, it has been revealed that egg-caring behaviour increases offspring survival and mating opportunities of egg-caring males through female mate choice, while it decreases the swimming and feeding abilities of the males as well as longevity. The behaviour would also decrease the survival rate due to predation. Although few previous studies have conducted field surveys, survival costs were detected in one study but not in another. In this study, we focused on the influence of field survey periods on the detection of egg-caring costs during the entire breeding season in the giant water bug, Appasus japonicus. Using a multi-state modelling approach, we found that the estimated survival rate was lower in egg-caring males compared to non-caring males and females. Furthermore, when we performed similar analyses during different periods (early and peak breeding season, peak breeding season, and peak and late breeding season) separately, the difference in survival rates was not clearly observed in the analyses of the former two periods, although it was still detected in the later period. Our findings suggest that paternal care in A. japonicus could incur survival costs and indicate the importance of survey timing and duration in assessments of parental costs.
Disturbance, hydrology and nest architecture were evaluated as drivers of reproductive outcomes in West African dwarf crocodiles (Osteolaemus tetraspis) over two breeding seasons (2021-2022) in Delta State, Nigeria. Surveys spanned culturally protected Emu (Ndokwa West LG) and more disturbed Okogbe and Esaba (Ehavbaren and Okpahoro) in Ughelli South LG, recording nest fate, architecture, microclimate and proximity to water; egg morphometrics (three Emu sites) and hatchling measurements (Emu vs Okopahoro/USLG) complemented field data. Non-parametric tests (Mann-Whitney; Kruskal-Wallis with Holm adjustment) and Cliff's delta quantified differences. A disturbance gradient was evident: Emu showed repeated nest reuse and successful hatching, whereas Okogbe and Esaba showed recurrent failure. Architecture tracked hydrology (Emu-Ndokwa West LG: deeper upper-egg placement/chamber bottoms; Ughelli South LG: greater cavity depth/mound height). Mean core temperature was 36.7 degrees C; clutches ranged between 15 and 27 eggs. Within Emu, eggs differed significantly among sites; between localities, Okogbe/USLG hatchlings were longer and heavier. Findings indicate that human pressure rather than microhabitat alone dominates nesting vulnerability and hatch success; architecture mitigates flood risk; and maternal traits with microenvironment jointly shape offspring phenotypes. Recommended actions include community co-management and targeted enforcement to reduce disturbance, hydrology aware restoration that treats mound elevation and cavity depth as functional design features, and instrumented monitoring (core temperature, water level, maternal metrics) to anticipate failure thresholds and sustain recruitment in a changing swamp forest mosaic.
Territorial defence is a key component of avian reproductive strategies, yet its regulation across breeding stages and competitive contexts remains poorly quantified in many raptors. In long-lived species, territorial behaviour should balance immediate risk management against long-term reproductive costs. Using a two-step hurdle modelling approach that separates the decision to initiate defence from the level of investment once defence occurs, we investigated how breeding stage and competitor density shape territorial behaviour in the Lanner falcon (Falco biarmicus), a fragmented Mediterranean raptor facing multiple sympatric competitors. We addressed statistical challenges including complete separation in binary response models and overdispersion in count data through penalized likelihood methods and simulation-based diagnostics. Across 155 behavioural observation sessions from 39 breeding attempts in eastern Sicily, we recorded agonistic responses to conspecific and heterospecific intruders during courtship, incubation and chick rearing. The probability of initiating defence was strongly shaped by competitor identity and density: Ravens (Corvus corax) consistently triggered aggressive responses, indicating a low tolerance threshold, whereas responses to Peregrine falcons (F. peregrinus) varied with breeding stage. Complete separation in standard logistic models required Firth's penalized likelihood, which confirmed the strong positive effect of Raven density and revealed a significant decrease in attack probability during chick rearing. In contrast, defence intensity was largely independent of competitor density and was primarily regulated by reproductive timing, peaking during courtship and declining through incubation and chick rearing. Substantial overdispersion in the Poisson model for defence duration cautions interpretation. Territorial defence showed parental symmetry, with males and females contributing equally, and defensive investment was not associated with fledging success or secondary sex ratio. Overall, findings indicate a hierarchical, state-dependent structure: external threats determine whether defence is initiated, while internal reproductive state constrains investment, suggesting territorial defence functions as flexible risk management rather than a direct driver of reproductive output.
Rupirana cardosoi is an endemic and threathened anuran species from the Chapada Diamantina region (Bahia, Brazil), with limited information available on its natural history, particularly its feeding behavior and diet. Using the stomach-flushing technique, we analyzed the stomach contents of 55 individuals collected in the Chapada Diamantina National Park (PNCD). We describe the species' diet and assess prey availability in the environment. Based on our findings, we classify R. cardosoi as an active forager and ant specialist, given its strong preference for ants compared to other prey categories available in the habitat. Consequently, we conducted a detailed identification of the Formicidae species consumed. The diet revealed a remarkable proportion of ants from species known to produce alkaloids and from species with aggressive defensive behaviors - typically a critical component in the diets of poisonous anurans or actively avoided by many frog species. Additionally, we documented the ant Anochetus horridus as a new occurrence for Bahia. Our findings highlight the value of anuran diet analysis for understanding the natural history of species, as it can provide insights into rare or novel arthropod species present in the environment through the examination of prey items.
This study establishes a comprehensive pre-impoundment ecological baseline for the Lower Gurara River, quantifying how physicochemical gradients structure fish assemblages across spatial and seasonal scales in advance of hydropower regulation. The assemblage comprised 3,831 individuals representing 15 species and 11 families, reflecting a typical West African tropical river community. Multivariate analyses identified two dominant environmental axes: a "hydraulic-oxygenation axis" associated with coarse substrates, high turbulence, and elevated dissolved oxygen in upstream reaches, and a "nutrient-ionic axis" that intensified progressively downstream with increasing conductivity, sulphate, and phosphate. These gradients corresponded closely with observed community patterns. Rheophilic and benthic foraging taxa were most abundant at well-oxygenated upstream stations (S1-S2), whereas generalist and disturbance-tolerant species dominated depositional, nutrient-enriched downstream habitats (S3-S4). Species richness remained constant across stations, but evenness declined and dominance increased downstream, indicating an altered assemblage structure rather than compositional turnover. Seasonal patterns showed strong wet-season increases in abundance driven by flood-pulse connectivity, while alpha-diversity metrics remained comparatively stable, consistent with hydrology-mediated dynamics in tropical rivers. Interannual increases in total abundance from 2021 to 2022 reflected regional hydroclimatic variability, particularly sensitivity of low flows and flood extent. Collectively, these results demonstrate that linked hydraulic-oxygenation and nutrient-ionic gradients offer a robust, mechanistic framework for interpreting fish assemblage responses. The baseline also identifies key sentinel stations, S2 for aeration sensitivity and S4 for enrichment, and thermal change, and supports the development of threshold-based monitoring dashboards to guide adaptive management following impoundment. This dataset provides a defensible reference condition crucial for safeguarding ecological integrity during and after hydropower development on the Lower Gurara River.
Amphibians can learn the odor of the environment in which they have undergone larval stages and use this information for orientation. For anurans, it was shown that learning does not occur throughout development, but only at certain stages that can be described as sensitive periods. However, no similar studies have been carried out for Urodela. Therefore, we investigated whether a sensitive period exists in the smooth newt (Lissotriton vulgaris) by rearing larvae in a chemically marked water. Two experimental and one control groups were formed: first reared in 10-7 mol/L morpholine solution from egg laying to stage 40 of development (inclusively) [1, 40], second from stage 42 (inclusively) until the juveniles emerged onto land [42, 56], and a control group that developed all stages in tap water without a marker. After metamorphosis, juveniles were tested in a T-maze for chemical marker odor recognition response. A statistically significant preference for morpholine was found only in the first group [1, 40], in other cases, the distribution did not differ from the random one. However, at higher temperatures, the response to the odor may change from preference to avoidance.
Human-carnivore conflict is a significant conservation and livelihood challenge in human-dominated landscapes. We examined the spatio-temporal and socio-economic factors influencing livestock depredation by Indian grey wolves (Canis lupus pallipes) in and around Mahuadanr Wolf Sanctuary, the first wolf sanctuary in India. Structured interviews were conducted with 345 households across 69 villages and integrated with ecological and anthropogenic predictors to assess patterns of wolf-induced livestock depredation and associated economic losses. More than half of the respondents (57.4%) reported losing livestock, with a total of 415 goats killed, corresponding to an estimated economic loss of Indian Rupee2.07 million during the study period. Depredation probability was significantly influenced by time of day, season, and location of attack, with events peaking at night and early morning and during winter and early-summer months. Geographically, open pastures and forests along the sanctuary boundary were the most risky places, whereas the rate of depredation was relatively lower near villages or within closed shelters. Proximity to the sanctuary boundary significantly increased household economic losses, whereas variables such as Sarna religion, Below Poverty Line status and goat-keeping structure showed weaker or non-significant effects. The results demonstrate that ecological opportunity and household vulnerability jointly shape wolf-livestock interactions in the Mahuadanr landscape. These findings highlight spatio-temporal and socio-economic factors associated with livestock depredation by wolves in eastern India.
Ambient light can have a marked influence on the behavior of many species, particularly prey animals, where increased illumination may raise the risk of predation while offering limited advantages for activities such as foraging and mating. Katydids, which depend on species-specific acoustic signals for long-distance communication, are known to be sensitive to environmental conditions. However, the impact of ambient light on paleotropic katydids remains unexplored. The current study explored the effect of ambient light, temperature, and humidity on katydid assemblages at two locations, one in Northeast India and the other in the Western Ghats, over 5 years (2015-2020). We examined possible differences across seasons and between ecosystems at each site. A total of 537 encounters through psychoacoustic monitoring were used for the analysis. The results showed that temperature and humidity had no significant impact. Ambient light had a significant effect on katydid activity, with overall activity peaking near the waxing phase, thereby indicating a strong influence of light. Comparison between ecosystems showed contrasting results across sites, activity peak being more closely associated with the understorey in the Western Ghats and with grasslands in Northeast India. Although elevated light may increase predation risk, especially in open habitats, the consequent impact on the activity level of individual species varies. While previous studies explore the effect of sympatric signallers and predators, our study is the first to explore how the natural environment might affect the signaling activity of katydid assemblages in the Paleotropics.
Understanding the temporal niche of different carnivores and their interactions with humans is crucial for conservation research. This study aimed to investigate the activity patterns of the carnivore community and their responses to human activities in the common leopard (Panthera pardus) distribution area of the Luoxu White-lipped Deer Nature Reserve, Sichuan Province, China. From September 2019 to October 2020, camera traps were used to obtain data on seven different carnivores. Kernel density estimation and generalised linear models were used to study the temporal niche partitioning of these carnivores and their reactions to human and livestock activities. Among the three types of large carnivores, common leopards preferred daytime and twilight and showed limited activity at night; the grey wolf (Canis lupus) preferred daytime; and brown bears (Ursus arctos) favoured twilight and night. Mesocarnivores there were nocturnal. The alpine weasel (Mustela altaica), a small-sized carnivore, was diurnal. The staggered activity peaks among these carnivores indicated temporal niche partitioning, which presumably reduced direct interspecific competition. Furthermore, the relative abundance index 2 (RAI2) of certain species was associated with different environmental and biological factors across different time periods. Common leopards showed no association with elevation during daytime but exhibited avoidance of grey wolf habitats. During twilight, their RAI2 increased at higher elevations and was independent of grey wolf distribution. Brown bear activity was not associated with human presence during daytime but shifted at night to areas that had been used by humans throughout the day. The RAI2 of common leopards showed a negative correlation with distance to settlements. Grey wolf daytime RAI2 was positively correlated with the RAI2 of humans and horses during the same time period. These findings inform management decisions and conservation efforts for ecological communities threatened with human encroachment.
Aggressive mimicry is an ambush strategy observed in various animal taxa, including snakes, which use caudal luring (CL) to attract prey. CL involves cryptically colored snakes waving a conspicuous tail tip (CTT) to mimic worm-like invertebrates, luring prey that feeds on such organisms. This strategy is common among Viperidae, particularly in juveniles, which often exhibit ontogenetic shifts in diet (OSD) from ectothermic to endothermic prey. Although CL, CTT and OSD are assumed to be correlated, this relationship has never been empirically tested. This study investigated the origin and persistence of CL, CTT and OSD in Viperidae evolution, assessing their phylogenetic signal and testing for correlations. Data on the presence or absence of these traits were compiled from the literature, and phylogenetic comparative methods were used to measure phylogenetic signal, test correlations and reconstruct ancestral character states using parsimony and maximum likelihood. Results revealed strong phylogenetic signals for all three traits and significant correlations between each pair. Maximum likelihood reconstructions suggested that the ancestral Viperidae possessed CL, CTT, and OSD, while parsimony analyses indicated CL and CTT were present in the ancestor, but OSD was not. These findings support the hypothesis that CL, CTT and OSD are evolutionarily linked and have been integral to Viperidae since their origin. Despite being the most comprehensive study on these traits, significant gaps in viper natural history data were identified. This highlights the need for further descriptive ecological studies to enhance understanding of viperid biology and support broader macroevolutionary research.
The trade-off between protection and mobility is a central principle in functional ecology and is particularly relevant in terrestrial hermit crabs, which depend on gastropod shells for defense while potentially incurring locomotor costs. Under the trade-off hypothesis, heavier or asymmetric shells are expected to impair movement, especially on heterogeneous or uneven substrates. To evaluate this prediction, we examined locomotor behavior in the land hermit crab Coenobita compressus on Coiba Island (Panama), integrating field observations with controlled experimental assays across substrates differing in topography and compaction. Contrary to classical expectations, shell weight and morphology exerted limited effects on locomotor performance. Instead, individuals exhibited substantial behavioral flexibility, adjusting posture and gait across environmental contexts. These findings suggest that C. compressus may buffer mechanical constraints imposed by shell architecture through adaptive behavioral compensation. Our results support an expanded interpretation of the trade-off framework in which behavioral plasticity attenuates, rather than eliminates, functional trade-offs, potentially enhancing performance in dynamic coastal habitats.
Animal personality is a concept in behavioural ecology that describes consistent inter-individual variation in behavior. These behavioral tendencies are stable across different contexts and throughout an individual's life. Increasing evidence shows that variation in individual personality of animals is related to variation in their cognitive ability (e.g. spatial learning), but the findings on such links are contradictory among and even within species. This study examined how personality traits (boldness and activity) relate to spatial learning in crucian carp (Carassius auratus), specifically to determine their reliance on allocentric (landmark-based) navigation. Fish were trained under two conditions: a visual landmark absent and present. As trials progressed, latency to complete the foraging task and theG number of fish turn-backs decreased in both treatments. However, the percentage of correct choices increased significantly only in the landmark present condition, with no marked improvement in the landmark absent condition. This indicates that the presence of a landmark enhanced learning efficiency, suggesting a reliance on allocentric navigation. Despite this, neither boldness nor activity predicted individual learning performance in landmark present context. Our findings demonstrate that environmental structure, specifically the presence of landmarks, is a critical factor in spatial learning for crucian carp, but the personality traits measured here do not underpin individual variation in this cognitive ability within the tested contexts.
The Swamp deer, also known as the Barasingha, is one of the largest species of deer in the Cervidae family. This study investigates the winter season food and feeding habits of Northern Swamp deer (Rucervus duvaucelii duvaucelii) in Dudhwa Tiger Reserve using vegetation sampling and microhistological analysis of fecal samples. Data were collected during the winter season (January--March 2024), randomly 98 sampling plots were laid at eight different locations within the study area. Ten m circular radius plots were laid along trails/roads at 100 m intervals on either side. In addition, pellet group collection was carried out within 10 m circular radius plots. To aid in the identification of species, 44 permanent reference slides were also prepared. The results showed that 97.4% of the diet consisted of grasses, out of the 28 food plants species that were detected. The results of this study also revealed that five species were consumed in proportion to their availability, 10 were less preferred species and eight were preferred species in the diet of swamp deer. The results based on winter season observations highlight the need to conserve important habitats, such as wetlands and grasslands, for the conservation of swamp deer and provide suggestions to conduct year-round research to better understand seasonal variations and enhance conservation strategies.
Locomotion is both a result and an impetus of morphology; though their interplay is an essential part of natural speciation, almost all domesticated species have been selectively bred so that their morphology better suits human needs. Where many species have been bred for function, many fish in the aquarium trade have been bred for aesthetics. Domesticated male Betta splendens have been bred for their large fins and are available in many varieties, but there is a lack of literature investigating the possible effects of this artificial selection on their behavior. The exaggerated large caudal fins of domesticated Betta are an artificially selected trait that is absent in wild Betta species, leading to questions regarding the possible effects of this selection on locomotion. To measure the effects of fin morphology on swimming behavior, we used a mixed-sex sample of several varieties of B. splendens and the closely related species B. imbellis to obtain a wide phenotypic range. We found that morphological characteristics associated with caudal fin size had a significant negative relationship with burst swimming speed, with caudal fin area and propulsive area ratio explaining the most variation in speed when adjusted for species, sex, and intra-individual variation. These results are consistent with patterns seen in similar studies of other small ray-finned fish and raise questions of the mechanical and behavioral costs of selective breeding in a common aquarium fish.
Growing urbanization affects ecosystems worldwide. Its ecological and evolutionary consequences are receiving increasing interest, on both fundamental and applied aspects. However, as for biodiversity knowledge in general, most studies have been conducted in Europe and North America, leaving other parts of the globe less explored. In Algeria, the Eurasian collared dove (Streptopelia decaocto) has a well-known settlement history and offers a unique opportunity to explore the potential phenotypic consequences of urbanization. Following up a previous study at the regional scale, we compared 13 morphological characteristics, body mass and two body condition indices (Body Condition Index or by Scaled Mass Index) of 35 Eurasian collared doves from two spatially close sites differing in their environmental characteristics (a woody cemetery and a roof-top surrounded by a highly urbanized area) 1.6 km apart within the city of Annaba itself, 20 years only after the species settled there. Some morphological traits were smaller in doves from roof-top compared to doves from woody cemetery, either significantly (extended and folded wing, finger and beak) or marginally (tarsus and beak height), while other traits did not differ (beak width, exposed and total culmen lengths, tail length, total body length, collar length, fifth primary feather length, bill index, relative wing length, body mass). Importantly, doves from both sites had similar body condition (whether estimated by BCI or SMI). In line with previous European and North American findings, these observations shed further light on the spatial (< 1 km) and the temporal (< 20 years) scale at which phenotypic differentiation may occur. Obtained on a limited sample size from two sites, our results highlight the urgent need for developing urban ecology studies in all parts of the world, including in overlooked regions such as Africa, to better understand the ecological and evolutionary consequences of urbanization and their underlying mechanisms worldwide.
Communication through scent-marking plays a crucial role in animal fitness, particularly for solitary species such as the Andean bear, in which it fulfills the function of advertising individual attributes to conspecifics and managing social interactions. However, research on the scent-marking behavior of Andean bears and the impact of free-ranging dogs on their chemical communication remains limited. This paper aims to characterize Andean bears' scent-marking behavior and to study the overlap of their daily activity patterns with free-ranging dogs in a key biological corridor linking the Andes to the Amazon region. We collected data using camera traps in front of 10 trees selected for rubbing by Andean bears. Cameras were deployed in the Gu & aacute;charos-Purac & eacute; Biological Corridor Regional Natural Park (PNRGP), Colombia, from April 2023 to April 2024. We determined the transition probabilities of marking behaviors using finite Markov chains. We compared the time budget for the behaviors displayed by Andean bears at rub trees by age and sex. Finally, we described the temporal overlap of Andean bears and free-ranging dogs and analyzed whether it differed between rainfall seasons. Results revealed significant intersexual differences in the time budget of scent-marking, with adult males investing more time on marking than females and subadults. This behavior was prevalent during the dry season. The daily activity patterns of Andean bears and free-ranging dogs were predominantly diurnal. Both species showed high temporal overlap during the dry season (77%), decreasing during the general analysis (75%) and the wet season (69%). We also suggest an increased potential for interspecific interactions between Andean bears and free-ranging dogs that could negatively impact the former, through competition, altered communication patterns and the potential transmission of diseases. We emphasize the need for further studies on the impact of free-ranging dogs on wildlife, particularly on the intraspecific communication of Andean bears.
