Search Results (70)

Anticoagulant rodenticides (ARs) are highly effective, but can be of environmental concern due to primary and secondary non-target exposure, with the latter possible being relevant to domestic cats. Therefore, liver residues of ARs and an alternative rodenticide, α-chloralose, were systematically monitored in domestic cats for the first time in the current study. In 2021 and 2022, the carcasses of 99 cats were collected in Slovenia and liver residues were measured by using solid supported liquid–liquid extraction and LC-MS/MS. The results show that 65% of cats carried at least one rodenticide. The second-generation ARs brodifacoum and bromadiolone were most prevalent and found in 53.5 and 25.3% of the samples, respectively. Of first-generation ARs, coumatetralyl was the most prevalent (21.2% of cats). More compounds were detected at high human population density, low farm density and in rural versus intermediate landscapes, but no effect was found for livestock density. Similar trends were found for the presence of brodifacoum, bromadiolone and all rodenticides combined. Farm density was negatively correlated with brodifacoum liver concentration. Individual factors (cat age, sex, outdoor activity) did not matter. The results indicate that a reasonably populated rural landscape, and not the rural or intermediate environment as such, is the main driver of cat exposure to ARs. The risk quotient (RQ) of worst-case acute brodifacoum poisoning was 1506. In summary, a potential environmental problem is globally highlighted for cats that is probably related to secondary exposure to ARs, with a pattern different to that seen in wild predators. Cats are an appropriate sentinel species for assessing rodenticide exposure and endangerment in the environment. Full article

Understanding how prey and predator species partition activity patterns across time and space is essential for elucidating behavioral adaptation and ecological coexistence. In this study, we examined the diel and seasonal activity rhythms of two sympatric rodent species—Rhombomys opimus (Great gerbil) and Meriones meridianus (Midday gerbil)—and their primary predators, Otocolobus manul (Pallas’s cat) and Vulpes vulpes (Red fox), in a desert-steppe ecosystem on the northern slopes of the Qilian Mountains, China. Using over 8000 camera trap days and kernel density estimation, we quantified their activity intensity and spatiotemporal overlap. The two rodent species showed clear temporal niche differentiation but differed in their synchrony with predators. R. opimus exhibited a unimodal diurnal rhythm with spring activity peaks, while M. meridianus showed stable nocturnal activity with a distinct autumn peak. Notably, O. manul adjusted its activity pattern to partially align with that of R. opimus, whereas V. vulpes maintained a crepuscular–nocturnal rhythm overlapping more closely with that of M. meridianus. Despite distinct temporal rhythms, both rodent species shared high spatial overlap with their predators (overlap index OI = 0.64–0.83). These findings suggest that temporal partitioning may reduce predation risk for R. opimus, while M. meridianus co-occurs more extensively with its predators. Our results highlight the ecological role of native carnivores in rodent population dynamics and support their potential use in biodiversity-friendly rodent management strategies under arid grassland conditions. Full article

Background/Objectives: Australian terrestrial mammals that fall within the critical weight range (35 g–5.5 kg) have experienced large population declines due to a combination of habitat loss and modification, and the introduction of non-native cats, dogs, and foxes. Because running speed typically increases with body size, predators are usually faster but less agile than their prey due to the biomechanical trade-offs between speed and agility. Quantifying the maximum locomotor capacities of Australian mammals in the critical weight range, and the magnitude of the trade-off between speed and agility, can aid in estimating species’ vulnerability to predation. Methods: To do this, we quantified the trade-off between speed and agility in both males and females (n = 36) of a critical weight range species, the northern brown bandicoot (Isoodon macrourus), and determined if there was an influence of morphology on locomotor performance. Results: When turning, individuals who had higher turn approach speeds, and higher within-turn speeds, had greater turning radii and lower angular velocities, meaning a decrease in overall maneuverability. Females were more agile and exhibited greater turning speeds at similar turning radii than males. For both sexes, individuals with longer relative hind digits had relatively faster sprint speeds, while those with longer forearms had relatively smaller turning radii and higher agility. Conclusions: Due to the constrained limb morphology of the bandicoot species, these findings could translate across this group to provide a better understanding of their escape performance and risk of predation. Full article

Understanding predator-prey coexistence mechanisms is essential for conserving endemic species in montane ecosystems. Galliformes serve as critical ecological indicator species, yet their populations are declining globally due to habitat fragmentation and anthropogenic pressures. Elliot’s pheasant (Syrmaticus ellioti, Swinhoe, 1872), a Galliformes species endemic to China, is primarily distributed south of the Yangtze River. However, its coexistence mechanisms with sympatric predators remain undocumented. Here, using six years (2019–2024) of camera-trap data from 90 stations in Jiemuxi National Nature Reserve, Hunan Province, Southwest China, we employed a MaxEnt model and kernel density estimation to investigate spatiotemporal coexistence mechanisms between Elliot’s pheasant and its primary predator, the leopard cat (Prionailurus bengalensis, Kerr, 1792). Across 36,946 camera-days, we obtained 227 independent detections of Elliot’s pheasant and 82 of the leopard cat. Spatial niche analysis revealed high overlap (Schoener’s D = 0.769; Hellinger’s I = 0.952). Both species exhibit similar preferences for main environmental variables. Conversely, significant temporal niche segregation occurred: Elliot’s pheasant displayed diurnal bimodal activity, whereas the leopard cat was strictly nocturnal, resulting in low overlap (Δ₄ = 0.379, p < 0.01). Critically, during Elliot’s pheasant’s breeding season, increased temporal overlap with the leopard cat (Δ₁ = 0.479, p < 0.01) suggested that reproductive behaviors elevate predation risk. Our findings demonstrate that temporal niche partitioning serves as the primary coexistence mechanism, while spatial niche overlap and behavioral adaptations under predation pressure drive dynamic predator-prey interactions. This provides a scientific foundation for targeted conservation strategies and predator management of these threatened Galliformes. Full article

The conservation of Siberian tigers, the apex predators in the Asia–Pacific region, hinges on a thorough understanding of their physiological statuses and adaptive mechanisms. In order to fill a critical gap in our knowledge of this endangered species, we conducted comprehensive analyses of Siberian tiger whole blood and serum using modern hematology and biochemical analyzers. The blood samples were collected from subadult (2–3 years old) Siberian tigers (n = 15 for hematological analysis and n = 7 for biochemical analysis). In the present study, distinct hematological patterns including an elevated mean platelet volume (MPV) and a higher red cell distribution width coefficient of variation (RDW-CV) were observed, which were possibly triggered by pre-anesthesia resistance movements. Notably, the neutrophil percentage in Siberian tigers was found to be significantly higher than that in domestic cats and Bengal tigers, suggesting species-specific immune adaptations. In addition, serum biochemical analysis provided refined parameter ranges for subadult tigers. Unlike previous studies encompassing a broader age range, our data specifically characterize biochemical profiles in subadult tigers, offering vital baselines for health monitoring and conservation strategies. These results not only enhance our understanding of the biology of Siberian tigers but also provide scientific support for targeted conservation efforts, fostering population recovery and ecological balance in their natural habitats. Full article

The introduction of alien species may pose an enormous threat to indigenous flora and fauna. Among introduced animals, probably the most destructive to the natural environment are mammals. This is true at least in regard to the Afrotropical Region (sub-Saharan Africa). This review attempts to summarize our knowledge on alien mammals in this region and their impact on indigenous vertebrate fauna. This review includes 56 mammal species, belonging to 20 families, introduced to sub-Saharan Africa over the last 2000 years. Most are representatives of the following orders: Artiodactyla, Carnivora, and Primates. Most species introduced to sub-Saharan Africa originated from the Oriental (n = 20) and Palearctic (n = 19) regions. Two species, Mus musculus and Rattus rattus, were introduced before 1400 (probably as early as 800 AD), while three others were introduced between 1401 and 1700. The first half of the 17th century saw the highest number (n = 10) of introduced species. Between 1651 and 1850, only two species were introduced; in the following 175 years (1851–2025), as many as 24 species were introduced. Ten of the introduced mammal species, namely Sus scrofa, Capra hircus, Rattus rattus, R. norvegicus, Mus musculus, Felis catus, Canis familiaris, Viverricula indica, Urva auropunctata, and Maccaca fuscicularis, have become invasive species. A total of 39 mammal species were relocated (mainly for hunting purposes) within sub-Saharan Africa. Most of them were representatives of the family Bovidae (76.9%). Relocations are not considered introductions. Based on published records of the impacts of alien mammals on the vertebrate fauna of sub-Saharan Africa, the following mechanisms may be distinguished: predation, competition, hybridization, transmission of diseases and parasites, and habitat destruction (grazing, herbivory, browsing). Most vertebrate species (79.4%) were affected through direct predation, predation and habitat destruction (7.1%), or predation and competition (1.4%). Alien mammals have caused habitat destruction for only 10 species (7.1%). Other effects (competition and genetic pollution) were marginal (3.5%). At least 144 vertebrate species, representing 52 families, have been affected by alien mammals in sub-Saharan Africa: 3 amphibians, 23 reptiles, 89 birds, and 29 mammals. As a result of mammal introductions, 65 species in sub-Saharan Africa have become globally extinct, 45 are considered threatened (listed in the RDB), and 31 other species are in decline, although not included in the RDB. Most extinct birds were affected by introduced rats, mice, feral cats, and dogs. In continental Africa, only seven vertebrate species have been negatively affected by alien mammals. All other affected vertebrates occur on islands. An especially high rate of extinction has been recorded in the Mascarene Islands. In comparison with alien birds in sub-Saharan Africa, the number of introduced mammal species is much lower, but their negative impact on vertebrate fauna is significantly greater. Full article

Urban free-roaming cats present challenges like noise, urination, defecation, property damage, public health risks, and wildlife predation. Traditional enforcement methods, such as containment laws and impounding, are ineffective, especially in low-income areas, where many free-roaming cats live. These cats are often cared for by “semi-owners”, who feed them without formal ownership. Financial barriers to sterilization for owned and semi-owned cats in these areas result in unplanned litters, sustaining the free-roaming population and burdening local authorities and animal welfare organizations. Cats causing complaints are frequently impounded and euthanized, affecting the mental health of veterinary, shelter, and council staff. This paper critiques punitive, compliance-driven strategies and highlights the success of assistive Community Cat Programs offering free sterilization, microchipping, and registration. In Banyule, Victoria, such a program reduced cat impoundments by 66%, euthanasia by 82%, and complaints by 36% between 2013 and 2021. Two other programs in large cities and rural towns in NSW and a rural town in Queensland have now reported similar results. Based on the One Welfare framework, these programs address the interconnectedness of animal welfare, human well-being, and environmental health. By removing financial barriers, they build trust between authorities and caregivers, improving compliance and welfare for cats, communities, and wildlife. However, following the loss of key program staff and the reintroduction of financial barriers in Banyule, cat intake rose by 140% between 2022 and 2024, demonstrating the detrimental impact of financial barriers and punitive approaches. This underscores the importance of sustained, community-based solutions and legislative reforms that prioritize humane, barrier-free strategies. Understanding the critical success factors for Community Cat Programs is essential for effective cat management. Full article

The cotton–melon aphid (Aphis gossypii Glover), a globally distributed polyphagous pest, primarily infests cucurbit crops and leads to significant reductions in both crop yield and quality. Overreliance on chemical insecticides has resulted in widespread resistance development, highlighting the urgent requirement for alternative control strategies. This study evaluates the potential of topical RNA interference (RNAi) for managing cotton–melon aphids. We first analyzed instar-specific expression profiles of four candidate RNAi target genes (ATPE, IAP, Cat, and ilvE), employed topical dsRNA delivery to silence these genes, and subsequently evaluated their effects on aphid mortality, growth rates, and reproductive capacity. Furthermore, we investigated the non-target effects of RNAi-treated aphids on the predator ladybird beetles Propylea japonica. The results indicate that topical dsRNA delivery successfully silenced the target genes, significantly impairing aphid development and fecundity while inducing mortality, with no adverse effects on the beneficial predator. This method provides a powerful tool for insect gene functional studies and a promising solution for RNAi-based pest management. Full article

The great desert skink (Liopholis kintorei, locally known as tjakuṟa) occupies burrow systems in arid regions of central Australia. Most burrow systems remain occupied for an average of 4, and up to 10, years by the same related individuals. The circumstances associated with changes in occupancy are under active investigation. Factors linked to tjakuṟa abandoning burrow systems include intense fires and predation by feral cats (Felis catus). We examined ecological factors associated with whether burrow systems that were occupied in the previous year were currently occupied by tjakuṟa. We determined occupancy of previously occupied tjakuṟa burrow systems by the presence of fresh scats in their latrines. We also assessed the size, vegetation cover, and proximity of termite calics to burrow systems. Neither overall vegetation cover nor spinifex cover was related to burrow system occupancy, but larger burrow systems were more likely to remain occupied. Burrow systems within 10 m of termite structures were more—and those within 2.5 m of Grevillea were less—likely to remain occupied by tjakuṟa. The role of woody vegetation (Grevillea) and termite presence on risk of predation, the behavior of tjakuṟa, and burrow system occupancy merits further investigation on a longer timescale. Full article

Urban free-roaming cat populations (or community cats, according to the Spanish legislation) present complex challenges, including public health risks, coexistence conflicts with residents, animal welfare, and threats to biodiversity conservation. In 2020, Córdoba, Spain, initiated one of the most extensive citywide trap–neuter–return (TNR) programs, incorporating 225 groups of cats (usually named colonies) into a meticulously structured management framework. Over four years, the program stabilized cat populations, achieving 95% sterilization coverage and effectively limiting population growth despite external challenges, including abandonment, influxes from unmanaged areas, and compensatory effects. Although the overall population showed a modest decline of 2.68%, this outcome reflects not only the recent inclusion of numerous colonies still undergoing stabilization but also the prevention of an estimated 70% population growth without intervention, as projected by our population viability analysis (PVA). Key results highlight the program’s cost-effectiveness, with an average annual cost of EUR 0.62 per person. The long-term projections from a population viability analysis (PVA) using demographic modeling suggest a potential 55% population reduction by 2028, contingent on sustained efforts. The program’s integration of citizen science, systematic data collection, and adaptive management demonstrates its scalability and replicability as a model for urban and peri-urban feline management globally. Its significance lies not only in its scope and scale but also in demonstrating the ethical and practical feasibility of large-scale TNR initiatives in urban contexts. Córdoba’s program, which predates Spain’s Animal Welfare Law 7/2023 mandating structured feline colony management plans, demonstrates a pioneering framework for compliance and innovation in urban animal management. These findings underscore the critical role of sustained interventions, community collaboration, and legal frameworks in ensuring long-term success and addressing global challenges in urban animal welfare and biodiversity conservation. Full article

La Graciosa, a Natura 2000 site in the Canary Islands, faces substantial conservation challenges, including a large free-roaming cat population that threatens the island’s native biodiversity. In July 2024, a Trap–Neuter–Return (TNR) campaign achieved an 81.4% sterilization rate within urban areas, highlighting TNR’s short-term effectiveness in reducing reproductive potential and, consequently, mitigating predation pressures primarily through the prevention of new litters and reduced reproductive activity in cats. The campaign’s success relied heavily on the active involvement of the local community, who assisted with identifying, trapping, and monitoring free-roaming cats, thereby facilitating a high sterilization rate. However, administrative restrictions hindered access to peri-urban zones, leaving essential population clusters unsterilized and limiting the campaign’s overall scope. Additionally, strong opposition from conservation groups, amplified by extensive media coverage, halted the project prematurely, reducing the effective sterilization rate to 69.3% within three months. Population Viability Analysis (PVA) suggests that achieving high sterilization rates could lead to population reduction over time; however, the inability to access all population segments and to reach the ideal 93–95% sterilization threshold limits TNR’s potential as a long-term standalone solution. Our findings underscore the need for adaptive, context-specific management frameworks in ecologically sensitive areas that integrate TNR with complementary measures, consider regulatory barriers, and value community involvement. This case study provides crucial insights for policymakers and conservationists seeking to balance biodiversity conservation with humane management practices in protected areas. Full article

Domestic cats (Felis catus) currently occupy the 38th place in the Global Invasive Species Database. Free-roaming cats potentially have broad-ranging impacts on wildlife, occupying most terrestrial environments globally as house pets, strays, or feral animals. In Australia, for example, cats are responsible for the decline in many vertebrate populations and extinction of several native mammals. However, in Brazil, few studies have explored either direct impacts of predation on wildlife, or other indirect impacts, such as competition for resources, niche overlap, hybridization, and disease transmission. In this review, we summarize and discuss 34 original research reports, published between 2001 and 2020, on impacts of free-roaming cats in Brazil. We briefly contextualize the history of cat domestication and present that, in Brazil, more studies have focused on the potential of free-roaming cats to transmit disease than to exert impacts via predation or competition on wildlife. More studies were conducted in Brazilian mainland areas (n = 23)—notably in Atlantic Forest—than on islands (n = 11). The review highlights potential impacts of cats on wildlife. We also discuss how control management strategies can affect the welfare of domestic cats, identifying potential knowledge gaps as well as opportunities for future research. Finally, understanding risks of cat predation is necessary to inform future measures to mitigate impacts on wildlife, without neglecting cat welfare. Full article

The effects of predatory natural enemies on their prey or hosts involve both consumption and non-consumptive effects. This study investigated the non-consumptive effects of the predator, Harmonia axyridis (Coleoptera: Coccinellidae) on 1st, 2nd and 3rd instar larvae of Spodoptera frugiperda. We exposed larvae of different instars to the predator and assessed various parameters using a combination of biological and biochemical methods. Exposure to the predator significantly affected the growth and development of the S. frugiperda caterpillars. Firstly, the developmental duration of S. frugiperda larvae in the 1st–3rd instars and the pupal stage were notably prolonged. Moreover, we observed significant effects on pupal mass, pupal abnormality rate and emergence rate. These non-consumptive effects were gradually weakened with an increase in the larval stage exposed to the predator. Antioxidant enzyme activities including catalase (CAT) peroxidase (POD) and superoxide dismutase (SOD) activity increased significantly. Additionally, organismal triglyceride, trehalose and glycogen content were significantly altered by non-consumptive effects, while protein content showed no significant change. Spodoptera frugiperda larvae increased the activity of antioxidant enzymes in response to potential predators to mitigate oxidative stress and reduce cellular and tissue damage. This resources redistribution towards survival may inhibit growth and development of the species and further exacerbate these non-consumptive effects. These findings highlight the importance of considering non-consumptive effects in pest-management strategies to optimize control measures in agricultural systems. Full article

This study simulated the effects of direct predatory pressure, indirect predatory pressure, and conspecific injury signals on sea cucumber (Apostichopus japonicus) to determine changes in the activity of immune defense enzymes (lysozyme, acid phosphatase, alkaline phosphatase) and antioxidant stress enzymes (catalase, superoxide dismutase, malondialdehyde). Samples of sea cucumber juveniles were collected at 3 h, 12 h, 72 h, and 96 h post predatory stress, and six enzymes related to immune defense and antioxidant stress were selected for activity assays, namely, lysozyme (LZM), acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). The results indicate that under direct predatory pressure, the activity of catalase in sea cucumbers was significantly higher than that of the control group at 3 h (P < 0.05), while the activities of acid phosphatase, alkaline phosphatase, and catalase were significantly lower at 72 h (P < 0.05). Under indirect predatory pressure, the activity of malondialdehyde in sea cucumbers was significantly higher than that of the control group at 12 h (P < 0.05), the activity of alkaline phosphatase was significantly higher at 72 and 96 h (P < 0.05), the activity of catalase was significantly lower at 72 h, and the activity of superoxide dismutase was significantly higher at 72 h (P < 0.05). Under the influence of conspecific injury signals, the activity of malondialdehyde in sea cucumbers was significantly higher than that of the control group at 12 h (P < 0.05), and the activity of superoxide dismutase was significantly higher at 96 h (P < 0.05). The sea cucumber enhanced its antioxidant capacity 3 h after facing a predator, while its immune defense mechanism was suppressed at 72 h. When facing indirect predatory pressure, the sea cucumber may have made immune and antioxidant preparations for the arrival of unknown risks. The experimental results show that predatory pressure has a significant impact on the immune and antioxidant functions of sea cucumbers, which may be related to the physiological state and environmental adaptability of the sea cucumber. This study provides a new perspective for understanding how sea cucumbers cope with predatory pressure in the natural environment and offers theoretical support for the cultivation management of sea cucumbers. Full article

Starvation is one of the main stresses for fish due to food shortage, the evasion of predators, and intraspecific competition. This research evaluated the impact of brief fasting periods on reactive oxygen species (ROS) levels, antioxidant response, mRNA expression of antioxidants, autophagy-related signaling genes, and autophagosome development in the muscle tissue of rice flower carp. Following a three-day fasting period, the levels of ROS and MDA rose. Additionally, after 3 d of fasting, there was a notable upregulation of NRF2 and significant increases in the levels of GSH and the activities of enzymes such as SOD, CAT, GST, GR, and GPX, while the expression of the autophagy marker gene LC3B did not change (p < 0.05). After 7 d of fasting, the content of the ROS, the activity of SOD and GR, and the GSH content reached the maximum (p < 0.05). Concurrently, there was a significant rise in the quantity of autophagosomes. An RT-qPCR analysis revealed that seven d of starvation significantly elevated the mRNA expression of genes associated with the initiation and expansion of autophagosome membranes, vesicle recycling, and cargo recruitment, including ULK1, BECLIN1, LC3B, ATG3, ATG4B, ATG4C, ATG5, ATG9, and P62. After feeding resumed for 3 d, the mRNA level of BECLIN1, ATG3, ATG4B, ATG4C, ATG5, LC3B, and P62 still remained at a high level. The LC3II protein reached its highest level. All autophagy-related gene expression decreased in the 7-day resumed feeding group. Our data implied that short-term fasting can cause oxidative stress and disrupt the antioxidant system first and then induce autophagy in the muscles of rice flower carp. These findings shed light on how fasting affects muscle homeostasis in fish. ROS-induced autophagy of the skeletal muscle may confer the resistance of rice flower carp to short-term fasting. Full article