Search Results (365)

Chinook salmon Oncorhynchus tshawytscha (Walbaum, 1792) is a non-native species in southern South America, where self-sustaining populations are established. After spawning migrations, adults die and provide substantial subsidies to freshwater food webs. We report the first direct evidence of predation on spawning Chinook salmon by South American sea lions Otaria byronia (de Blainville, 1820) in a river of southern Chile, up to 160 km upstream from estuaries. Sea lions appear to be exploiting a novel prey resource, indicating behavioral plasticity with potential ecological consequences for native species and riverine trophic dynamics. We discuss the implications of this previously unreported predator–prey interaction for the ecology of invaded freshwater systems in South America. Full article

Climate change is increasingly altering the ecological dynamics of apple orchard ecosystems, creating new challenges for sustainable management of phytophagous mites. Rising temperatures, prolonged drought periods, and increasing climatic variability influence mite population dynamics, destabilize predator–prey interactions, and reduce the effectiveness of traditional pest management approaches. This review examines sustainable mite management in apple orchards through the interconnected perspectives of ecological stability, climatic stress, and resilience-oriented agroecosystem management. Particular attention is given to the ecological mechanisms underlying mite outbreaks, including climate-driven acceleration of reproduction, trophic destabilization, biodiversity loss, and disruption of biological regulation processes. The ecological limitations of both conventional chemical control and biological control strategies are critically analyzed, highlighting issues related to pesticide-induced ecological disturbance, resistance development, climatic sensitivity of natural enemies, and operational constraints. The review further explores resilience-oriented management frameworks based on ecological intensification, habitat diversification, conservation biological control, adaptive management, and system-oriented regulation. Current research gaps are identified, including the lack of long-term ecological studies, insufficient integration of climatic and ecological datasets, limited development of resilience indicators, and underrepresentation of continental and semi-arid orchard systems. The findings suggest that future sustainable mite management should move beyond reactive pest suppression toward ecosystem-based approaches that strengthen ecological resilience and adaptive capacity under increasing climatic uncertainty. Full article

Diet diversity of owls has traditionally been studied using prey taxonomic composition, but species identities alone do not necessarily capture ecological roles, energetic dominance, or evolutionary breadth of prey. Here we quantified diversity across taxonomic, functional, and phylogenetic dimensions of prey of nine European owl species: Aegolius funereus, Asio otus, Athene noctua, Bubo bubo, Glaucidium passerinum, Otus scops, Strix uralensis, Strix aluco, and Tyto alba. Using a unified Hill-number framework we estimated richness- and evenness-sensitive diversity and evaluated prey assemblage structures using standardized effect sizes from richness-controlled null models. Prey diversity varied strikingly among owls. Diet strongly relied on a limited set of functionally and phylogenetically similar prey. Bubo bubo showed high richness but low evenness, Otus scops specialization, Glaucidium passerinum high evenness, and Athene noctua high phylogenetic breadth. Large differences in taxonomic richness were frequently decoupled from functional or evolutionary breadth, for example in Bubo bubo and Athene noctua. Structural analyses revealed phylogenetic overdispersion in Athene noctua and Otus scops, clustering in Glaucidium passerinum, and extreme functional clustering in Tyto alba and Asio otus. Together, these results show that owl diets are structured along multiple, partially independent axes, best revealed by combining Hill-number profiles with null-model analyses. Full article

This study examines a discrete fractional-order predator–prey system incorporating a Holling type-III functional response. The Caputo fractional derivative is employed because it naturally incorporates memory and hereditary effects while preserving biologically meaningful initial conditions. The system is formulated from a biologically relevant continuous fractional-order framework through the application of the piecewise constant argument approach, enabling an analysis of how memory-dependent effects and discrete dynamics influence predator–prey interactions. The existence and local stability of fixed points are determined by using the Jacobian matrix and eigenvalue conditions. The bifurcation of the positive fixed point is analyzed by using the center manifold and normal form methods. Numerical simulations, including bifurcation diagrams, phase portraits, and maximum Lyapunov exponent plots, confirm our analytical results and reveal periodic, quasiperiodic, and chaotic behavior. The findings of this study reveal that the combined influence of memory-dependent dynamics, nonlinear predator–prey interactions, and discrete-time effects can generate rich and complicated behaviors in fractional-order predator-prey systems. Full article

Plants can provide natural enemies with alternative food resources that enhance their performance in addition to prey consumption. Extrafloral nectaries attract beneficial insects by supplying nectar in exchange for pest suppression, although other arthropods may also benefit. This study aimed to characterize the extrafloral nectar composition of bottle gourd, Lagenaria siceraria (Molina) Standley (Cucurbitaceae), a host plant of Nesidiocoris tenuis Reuter (Hemiptera: Miridae), and to evaluate the effects of its carbohydrate profile on key biological parameters of this predator. Extrafloral nectar was chemically characterized for carbohydrate and amino acid composition, and laboratory bioassays were conducted to assess the effects of a sugar solution of the extrafloral nectar carbohydrate profile when provided with two factitious food sources, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs and Artemia sp. (Anostraca: Artemiidae) cysts. Female egg production, nymphal development and food source consumption were evaluated. Chemical analysis revealed that bottle gourd extrafloral nectar consisted primarily of glucose, fructose, sucrose and melezitose, while serine was the dominant amino acid. Four essential amino acids were also detected. Sugar supplementation did not affect nymphal development rate but significantly reduced factitious food consumption. Significant differences in egg production were observed among feeding regimes. Sugar supplementation did not affect egg production when E. kuehniella eggs were provided, but significantly increased egg production when Artemia cysts were used as food source. These results indicate that extrafloral nectar carbohydrates can function as effective supplementary nutritional resources for N. tenuis, particularly when lower-quality factitious food sources are used. These findings enhance our understanding of plant–predator nutritional interactions and suggest that extrafloral nectar-derived components warrant further evaluation for incorporation into mass rearing protocols. Full article

Biological invasions and freshwater biodiversity loss are two of the most pressing global conservation challenges yet their interaction during the earliest stages of invasion remains poorly understood. Iberian freshwaters rank among Europe’s most biodiverse ecosystems, harbouring a remarkable assemblage of endemic fish species. This irreplaceable heritage is increasingly threatened by non-native piscivorous predators, to which endemic species often lack innate antipredator responses. The invasive European perch (Perca fluviatilis) was first detected in the Meimoa reservoir, within the Malcata Natural Reserve (Central Portugal), in 2023, and has since expanded exponentially in abundance while dispersing into adjacent stream networks. This emerging invasion provided a unique opportunity to assess the predation impacts of a novel piscivorous predator during the early stages of establishment and dispersion, across both lentic and lotic habitats. From 2022 to 2025, European perch were sampled in the invaded reservoir using gillnetting and in connected streams with electrofishing. Diet was assessed through stomach content analysis, and prey composition was analyzed in relation to site, season, year and ontogeny. European perch exhibited a clear ontogenetic diet shift as expected, from zooplankton and invertebrates to crayfish and fish, with minor variation in prey composition between systems. In the Meimoa reservoir, body size was the strongest driver of diet composition (PERMANOVA: R² = 0.134, p < 0.001), with 50% of the stomachs from individuals above 35 cm containing fish, with the Iberian nase, Pseudochondrostoma polylepis, being the dominant prey. Diet composition remained stable across years (R² = 0.007; p = 0.188), despite a 74% decline in nase catch per unit effort (CPUE) between 2022 and 2025. In streams, despite the absence of large perch, piscivory was recorded earlier and encompassing a broader range of native taxa. The sustained predation pressure on P. polylepis, a formerly dominant and culturally significant species, despite its steep population decline, suggests that European perch holds the potential to locally deplete native fish stocks. The advance of this predator into lotic habitats demands urgent conservation action, as it may critically threaten the long-term persistence of one of Portugal’s most vulnerable freshwater taxonomic groups. Full article

The tomato leafminer Tuta absoluta (Meyrick) is a devastating invasive pest that threatens tomato production worldwide. Reliance on chemical insecticides raises sustainability concerns, highlighting the need for effective biological alternatives. Combining predators with entomopathogenic nematodes (EPNs) represents a promising strategy, yet their interactions remain poorly characterized. Here, we conducted laboratory bioassays to assess the individual and joint effects of the predatory bug Arma chinensis (Fallou) and four EPN species, Steinernema carpocapsae, S. feltiae, S. riobrave, and Heterorhabditis bacteriophora, against T. absoluta larvae. Under these controlled conditions, H. bacteriophora showed the highest compatibility with A. chinensis, exhibiting the lowest virulence against the predator. Female A. chinensis exhibited strong predation on freely exposed second-instar larvae, but efficiency declined markedly against leaf-mining larvae. Heterorhabditis bacteriophora caused consistently high mortality in second instars regardless of protection. Their combined application resulted in additive mortality with significantly reduced LT₅₀ values. We also observed A. chinensis preying on nematode-infected larvae and occasional infection of the predator under confined conditions. These laboratory findings demonstrate additive effects against T. absoluta, providing preliminary evidence for stage-specific integrated biological control strategies. Full article

Silicon (Si) amendment can enhance plant resistance to biotic stress, yet its role in tri-trophic interactions under multiple herbivore attack remains unclear. This study examined how Si influences herbivore-induced plant volatiles (HIPVs) and the foraging behavior of the predatory mirid Cyrtorhinus lividipennis that preys on eggs of the white-backed planthopper (WBPH; Sogatella furcifera). A 2 × 2 factorial design was employed to test the effects of Si amendment (+Si vs. −Si) and the striped stem borer (SSB; Chilo suppressalis) infestation (+SSB vs. −SSB) on plant volatile emissions and predator behaviors, with WBPH infestation present in all treatments. Cage and Y-tube experiments showed higher predator attraction and increased WBPH egg predation in +Si+SSB treatment relative to −Si+SSB treatment. HS-SPME-GC/MS analysis revealed that, regardless of Si amendment, SSB infestation massively altered the overall volatile profile, while Si amendment reduced emission of many volatiles in SSB infested plants. Single compound bioassays further identified that, regardless of Si amendment, SSB infestation significantly up-regulated four repellents for C. lividipennis. Compared with the −Si+SSB treatment, the +Si+SSB treatment down-regulated one repellent volatile and up-regulated three attractant volatiles. These findings indicate that Si amendment potentially enhances biocontrol of the subsequent herbivore under dual herbivory through altering HIPV emissions induced by the prior herbivory. Full article

This study analyzes a modified Holling–Tanner predator–prey system with linear harvesting and supplementary food for the predator. The framework examines how harvesting interacts with predation and external resources to determine system dynamics. We derive explicit conditions for the existence and stability of all equilibria and identify a critical predation threshold separating stable coexistence from oscillatory dynamics. Harvesting acts as a control parameter that can suppress oscillations, eliminate interior equilibria, and drive the system toward a prey-free state. We establish sufficient conditions for pest eradication by linking harvesting intensity, predation rate, and the loss of coexistence equilibria. Local bifurcation analysis reveals Hopf and saddle–node bifurcations, marking transitions between steady states and periodic oscillations. For the spatially extended system, diffusion-driven instability is investigated, and conditions for Turing pattern formation are derived from the modified equilibrium structure. Numerical simulations support the analytical results and illustrate transitions between dynamical regimes under varying harvesting levels. The results provide explicit parameter thresholds governing stabilization, oscillation, and eradication in predator–prey systems with external resource support. Full article

Human disturbances, such as habitat destruction and overharvesting, are greatly harming ecosystems and causing significant declines in biodiversity. Although protected areas play a crucial role in conserving terrestrial mammals, nearly non-protected areas (N-PAs) have similar functions, harbor high biodiversity and ecosystem integrity, and deserve to be protected. To identify the conservation value of mammalian species in critical ecosystems within N-PAs, we conducted a camera-trap survey in Luolong County, Tibet, from November 2019 to June 2023, monitoring 159 sites and documenting 25 mammalian species across 28 similar or dissimilar habitats. We found this area was an integrity ecosystem with higher species richness and diversity in scrub and evergreen forests with notable occurrence of herbivores comprising musk deer, chinese serow, woolly hares and carnivores such as the common leopard, snow leopards, red foxes and stone marten. Mammalian species occurrence increased away from human activities. Different habitats and seasons influenced diversity and species interactions. Key findings include species preferences for specific habitats, such as blue sheep on southern slopes during snow, musk deer in mixed forests, and red foxes avoiding alpine meadows. Habitat type, elevation, and human disturbance significantly impacted species distribution and behavior. The study also found that snow leopard activity time negatively correlates with woolly hare, while common leopards are influenced positively by hares and negatively by brown bears. Red foxes are slightly more active near the chinese serow occurrence areas. Other predators and prey, such as eurasian lynx, gray wolves, musk deer and stone martens show specific seasonal and interspecific interactions, with some relationships explaining small portions of variation. Overall, species temporal detection events are interconnected through complex ecological interactions. These findings improve our understanding of habitat hosting for rare species and the balance of endangered prey and predator communities in N-PAs in Tibet, emphasizing their significance for conservation efforts. Full article

Gastrotrichs (Phylum Gastrotricha) are widespread and species-rich components of benthic and periphytic communities, where they are thought to contribute substantially to food-web functioning by linking the microbial loop to higher trophic levels through their feeding on detritus, bacteria, microalgae, and fungi, and serve as prey for larger animals. Despite the well-recognized role as primary consumers, their position as potential prey remains largely unresolved, with documented predators so far restricted to carnivorous protists. Here, we report the first documented case of metazoan predation on a freshwater gastrotrich, in which a cyclopoid copepod actively captures and partially consumes a chaetonotid species. The interaction was first detected under minimally disturbed conditions and subsequently replicated in controlled experimental settings. Predation was documented through in vivo video recordings and supported by species-level identification of both predator and prey. These findings expand the currently recognized trophic interactions involving freshwater gastrotrichs and provide new insight into their ecological role within aquatic food webs. Full article

Predators can exploit chemical signals of social insects to locate prey. Ants are considered as major predators of termites, and the interactions between them have been shaped by a long evolutionary history. Here, we investigated whether the ant Odontoponera transversa exhibits differential responses towards three termite species: Coptotermes formosanus, Ancistrotermes dimorphus, and Macrotermes barneyi. Through a combination of field trapping experiments and laboratory behavioral assays, we found that O. transversa showed stronger predatory responses towards A. dimorphus and M. barneyi than towards C. formosanus. Furthermore, when A. dimorphus or M. barneyi was present, attacks on C. formosanus were rarely observed, suggesting a hierarchy in prey preference. Behavioral assays indicated that termite trail pheromones serve as key cues influencing ant foraging decisions. Our findings suggest that differential responses to chemical signals, particularly trail pheromones, may underlie the observed prey preference patterns in O. transversa. Together, these results demonstrate that chemical signals, particularly trail pheromones, are key determinants of prey preference in O. transversa, offering a foundation for understanding the chemical ecology of ant–termite interactions. Full article

The Kangaroo Escape Optimizer (KEO) is a recently proposed biomimetic metaheuristic inspired by the adaptive escape strategies of kangaroos in predator–prey interactions. Although effective, KEO-like algorithms based on many populations may suffer from premature convergence and loss of population diversity when addressing complex, multimodal, and constrained optimization problems. This paper proposes an Enhanced Kangaroo Escape Optimizer (EKEO) that integrates Differential Evolution Mutation (DEM) and Quasi-Oppositional Learning (QOL) to address fundamental limitations in exploration–exploitation balance. From a biomimetic perspective, DEM mimics the refined high-frequency muscular adjustments of a kangaroo during close-range evasion, enabling local refinement around promising solutions, while QOL emulates the animal’s sudden directional changes and scanning behavior to preserve population diversity and escape local optima. Their principled integration yields a robust optimization framework that consistently outperforms state-of-the-art and classical metaheuristics across benchmark functions and real-world engineering problems. The findings suggest a generalizable design principle for biomimetic hybrid metaheuristics, demonstrating that coupling directed exploitation with diversity-preserving exploration leads to reliable high-performance optimization. The performance of EKEO is rigorously evaluated in two phases. First, its optimization accuracy and convergence speed are benchmarked against 11 state-of-the-art and classical metaheuristics on 23 classical benchmark functions and the CEC 2019 test suite. Second, its practical applicability and constraint-handling effectiveness are validated on four real-world engineering design problems: step-cone pulley, gear system, tubular column, and pressure vessel design. The experimental results are supported by comprehensive statistical analyses (including Wilcoxon rank-sum tests) and convergence curves, showing that EKEO consistently outperforms its competitors in solution quality, convergence speed, and robustness. These findings establish EKEO as a competitive, reliable, and versatile biomimetic optimization tool suitable for solving complex continuous and constrained engineering optimization problems. Full article

This paper investigates a discrete-time fractional-order predator–prey model incorporating a double Allee effect in the prey population, derived from a fractional differential system via the piecewise constant argument method to capture both memory effects and density-dependent constraints. We establish the existence and local stability of all biologically meaningful equilibria and show that the interaction between fractional memory and the double Allee threshold significantly influences the stability of the coexistence state. Through the integration of linear stability analysis and center manifold reduction, we are able to obtain explicit conditions for Neimark–Sacker and period-doubling bifurcations. The system exhibits rich dynamics, including periodic oscillations, quasi-periodicity, and chaos. The double Allee effect plays a key role in shaping system stability. To suppress instability and chaotic behavior, feedback and hybrid control strategies are applied and shown to be effective. Numerical simulations are given to confirm the results obtained by the theoretical analysis and to show the transitions among different dynamical states, in which the fractional-order memory and multiple Allee effects play important roles. Full article

Thisarticle develops and analyzes a fractional-order Leslie–Gower prey–predator–parasite system incorporating two discrete delays and nonlocal spatial diffusion. The model’s central novelty lies in the simultaneous integration of three biologically realistic features that have not previously been combined: (i) fractional-order memory effects via a Caputo derivative of order $\alpha \in (0,1]$, (ii) two distinct biological delays—an infection transmission delay ${\tau }_1$ and a predator handling delay ${\tau }_2$—and (iii) nonlocal spatial dispersal modeled through fractional Laplacian operators ${(-\Delta )}^{\gamma /2}$. This triple integration enables the model to capture long-range temporal memory, delayed biological responses, and nonlocal spatial interactions simultaneously, offering insights into dynamics that are challenging to capture with classical integer-order or single-delay formulations. The fractional Laplacian generalizes classical diffusion by allowing long-range dispersal events (Lévy flights), where individuals can occasionally move over large distances with heavy-tailed step-size distributions—a phenomenon observed in many animal movement patterns but absent from standard diffusion models. We provide rigorous proofs of solution existence, uniqueness, non-negativity, and boundedness in both temporal and spatiotemporal settings. Local asymptotic stability conditions are derived for all feasible equilibrium states via characteristic equation analysis. The coexistence equilibrium undergoes a Hopf bifurcation when either delay crosses a critical threshold, with fractional order $\alpha$ modulating the bifurcation point and post-bifurcation oscillation frequency. A Lyapunov functional demonstrates global asymptotic stability of the infection-free equilibrium under biologically interpretable conditions. Turing instability analysis reveals conditions for spontaneous pattern formation, with the fractional exponent $\gamma$ controlling pattern wavelength and correlation length. Numerical simulations validate theoretical predictions, including spatial patterns, traveling waves, and chaos. To bridge theory with potential applications, we outline a statistical framework for parameter estimation and uncertainty quantification, suggesting that $\beta$, $\alpha$, and ${\tau }_1$ may be priority targets for parameter estimation. Full article