Predatory Behavior Research Articles

Molecular analysis of scats revealed diet and prey choice of grey wolves and Eurasian lynx in the contact zone between the Dinaric Mountains and the Alps

A comprehensive understanding of the dietary habits of carnivores is essential to get ecological insights into their role in the ecosystem, potential competition with other carnivorous species, and their effect on prey populations. Genetic analysis of non-invasive samples, such as scats, can supplement behavioural or microscopic diet investigations. The objective of this study was to employ DNA metabarcoding to accurately determine the prey species in grey wolf (Canis lupus) and Eurasian lynx (Lynx lynx) scat samples collected in the Julian Alps and the Dinaric Mountains, Slovenia. The primary prey of wolves were red deer (Cervus elaphus) (detected in 96% scat samples), European roe deer (Capreolus capreolus) (68%), and wild boar (Sus scrofa) (45%). A smaller portion of their diet consisted of mesocarnivores, small mammals, and domestic animals. In contrast, the lynx diet mostly consisted of European roe deer (82%) and red deer (64%). However, small mammals and domestic animals were also present in lynx diet, albeit to a lesser extent. Our findings indicate that the dietary habits of wolves and lynx are influenced by geographical location. Snapshot dietary analyses using metabarcoding are valuable for comprehending the behaviour and ecology of predators, and for devising conservation measures aimed at sustainable management of both their natural habitats and prey populations. However, to gain a more detailed understanding of wolf and lynx dietary habits and ecological impact, it would be essential to conduct long-term genetic monitoring of their diet.

Global boundedness and stability of a predator–prey model with alarm-taxis

This paper deals with the global boundedness and stability of classical solutions to an important alarm-taxis ecosystem that is significant in understanding the behaviors of prey and predators. Specifically, it studies the case where prey attracts the secondary predators when threatened by the primary predators. The secondary consumers pursue the signal generated by the interaction between the prey and direct consumers. However, obtaining the necessary gradient estimates for global existence seems difficult in the critical case due to the strong coupled structure. Therefore, a new approach is developed to estimate the gradient of prey and primary predators, which takes advantage of slightly higher damping power. Subsequently, the boundedness of classical solutions in two-dimension with Neumann boundary conditions can be established by energy estimates and semigroup theory. Moreover, by constructing Lyapunov functional, it is proved that the coexistence homogeneous steady states are asymptotically stable, and the convergence rate is exponential under certain assumptions on the system coefficients.

Beyond the kill: The allometry of predation behaviours among large carnivores.

The costs of foraging can be high while also carrying significant risks, especially for consumers feeding at the top of the food chain. To mitigate these risks, many predators supplement active hunting with scavenging and kleptoparasitic behaviours, in some cases specializing in these alternative modes of predation. The factors that drive differential utilization of these tactics from species to species are not well understood. Here, we use an energetics approach to investigate the survival advantages of hunting, scavenging and kleptoparasitism as a function of predator, prey and potential competitor body sizes for terrestrial mammalian carnivores. The results of our framework reveal that predator tactics become more diverse closer to starvation, while the deployment of scavenging and kleptoparasitism is strongly constrained by the ratio of predator to prey body size. Our model accurately predicts a behavioural transition away from hunting towards alternative modes of predation with increasing prey size for predators spanning an order of magnitude in body size, closely matching observational data across a range of species. We then show that this behavioural boundary follows an allometric power-law scaling relationship where the predator size scales with an exponent nearing 3/4 with prey size, meaning that this behavioural switch occurs at relatively larger threshold prey body size for larger carnivores. We suggest that our approach may provide a holistic framework for guiding future observational efforts exploring the diverse array of predator foraging behaviours.

Ethical dilemmas and copyright challenges among independent artists in Kenya's music industry

This qualitative phenomenological study investigates the ethical dilemmas surrounding revenue generation and copyright practices among independent Kenyan artists. Through an extensive analysis of existing literature and qualitative data, the study delves into various aspects including copyright laws, governmental policies, and collective management organisations (CMOs), exploitative practices, and regulatory frameworks. It uncovers that while Kenya's music industry has experienced significant growth with the rise of new music genres and disruptive innovations, it still grapples with systemic barriers that impede the success and welfare of independent artists. Copyright laws and governmental policies revealed gaps in safeguarding independent artists' intellectual property rights. With a close examination of CMOs, the study shed light on issues such as mismanagement, corruption, and failure to distribute royalties to artists fairly, thus calling for the need of increased transparency and accountability. These issues are linked to the numerous challenges, including limited access to resources, inadequate industry support, and unfair compensation. Exploitative practices carried out by industry players and intermediaries are subjecting independent artists to unjust contractual agreements, withheld royalties, and predatory behaviours from industry players. The existence of weak regulations magnifies these issues, resulting in the erosion of artists' rights and minimal recourse in cases of copyright violations or contractual disputes. This study, therefore, advocates for regulatory reforms and industry-wide interventions to address these systemic barriers and to shed light on how to foster a more equitable and sustainable music ecosystem in Kenya. Last, the study recommends the strengthening of copyright enforcement mechanisms, improving transparency and accountability within CMOs, and establishing tailored support systems for independent artists.

Catastrophic and noncatastrophic population crashes in a bitrophic system with dynamic additional food provision to cooperative predators.

In this article we contemplate the dynamics of an additional food-provided prey-predator system. We assume that the behavior of cooperative predators induces fear in prey, which radically affects the prey's birth and death rates. We observe that the structural instability imposed by strong cooperative hunting among predators goes away with higher intensities of fear levels affecting the prey's reproductive output and mortality. High levels of prey refuge are not conducive to the survival of predators. In such a situation, adequate supply of high-quality additional food is favorable regarding the persistence and stability of the system. Interestingly, the system potentially exhibits two stable configurations under identical ecological conditions by allowing different bifurcation scenarios, including saddle-node and backward bifurcations, and associated hysteresis effects with prey refuge along with additional food quantity and quality. In the stochastic environment, the system experiences critical transitions through bifurcation-induced tipping events with time-varying additional food for predators. Enhanced disturbance events promote noise-induced switching and tipping events. Finally, our investigation explores whether impending population crashes resulting from the variability of additional food quantity and quality can reliably be predicted using early warning signals in the context of redshifted noise. Overall, our results may provide insights for finding control strategies in the context of community ecology.

Crow and Raven in Lithuanian and Slavic Phraseology and Ethnic Culture

The aim of the article is to explore whether the image of the crow and raven in Lithuanian phraseology and ethnic culture is similar to that of its Slavic neighbors or exhibits distinctive characteristics. The research material includes phraseological units in Lithuanian, Polish, Belarusian, and Russian with the components crow and raven. The analysis encompasses phraseologisms found in both vernacular and literary sources, applying the theory of conventional figurative language and the comparative method. Special attention is given to the portrayal of crows and ravens in folklore and folk beliefs. The findings reveal a predominantly negative perception of both birds in Lithuanian and Slavic phraseology and ethnic culture. The main features of the image of a crow and raven, which have developed in Lithuanian and Slavic phraseology and ethnic culture, are based on such characteristics as: black feathers, predatory behaviour, an unpleasant voice (the cry is mythologized, and it is associated with misfortunes and death). The image of the crow is often ironic and comical, while the image of the raven is much more negative. The crow is a cultural symbol of foolishness, while the raven is associated with wisdom. However, both Lithuanian and Slavic phraseology have their own peculiar images of the crow and the raven.

A food quality detection method based on electronic nose technology

Food quality detection is of great importance for human health and industrial production. Currently, the common detection methods are difficult to achieve the need for fast, accurate, and non-destructive detection. In this work, an electronic nose (E-nose) detection method based on the combination of convolutional neural network combined with wavelet scattering network (CNN-WSN) and improved seahorse optimizes kernel extreme learning machine (ISHO-KELM) is proposed for identifying the quality level of a variety of food products. In the feature extraction part, the abstract features of CNN are fused with the scattering features of WSN, and the obtained CNN-WSN fusion features can characterize the original information of the food quality effectively. In the classifier design and decision-making section, chaotic mapping is used to initialize the population in the seahorse optimisation algorithm (SHO), avoiding the problem that SHO may fall into local optimal solutions. The kernel parameters and regularisation coefficients of the KELM model were then optimized by improving the locomotion, predation, and reproduction behaviors of the hippocampal populations, which solved the problem of the difficult selection of the key parameters in the model, and thus improved the accuracy and generalization of the overall model. To validate the effectiveness of the proposed food quality detection model, the E-nose system was first built and milk quality data were collected independently, and then tested on two publicly available food quality datasets as well as a self-collected milk quality dataset, respectively. The experimental results show that the food quality detection method proposed in this work has good quality assessment effect on different datasets.

In vitro comparison of two food choice methodologies for necrophagous species of the genus Thanatophilus (Coleoptera: Staphylinidae: Silphinae).

To accurately model the food webs, we need to acquire precise data on food ecology of the interacting species. This allows better understanding of the trophic interactions and for the necrophagous species this information could be used in medico-legal investigations. For this reason, we recently proposed standardized laboratory methodology to assess the foraging strategies based on parallel testing of 2 food items (meat, dead larvae) (Jakubec et al. 2021). The original methodology had 2 shortcomings. It was not suited for testing living larvae, which could prove predatory behavior of the species. The methodology was also based on parallel experimental design, where the food items are tested together, which could underestimate the maximum consumption of the tested subject for some items. To test if these concerns are valid, we improved original methodology allowing testing living larvae as well as a new sequential experimental setup, where consumption of each item is tested individually in a random order, thus theoretically giving an unbiased maximum consumption estimate. These methodologies were tested head-to-head on 3 forensically relevant species from the genus Thanatophilus (Thanatophilus micans (Fabricius 1794)(Fabricius 1794), Thanatophilus rugosus (Linnaeus, 1758), and Thanatophilus sinuatus(Fabricius, 1775)). The experiments have confirmed that all 3 species are almost strictly necrophagous, although they were capable of predation, despite the presence of preferred food (meat). The comparison also showed that the sequential design has indeed improved capability to quantify the maximal consumption of the given food item. Thus, we suggest following this methodology in future studies.

The nightscape of the Arctic winter shapes the diving behavior of a marine predator

Predator–prey interactions in marine ecosystems are dynamically influenced by light, as demonstrated by diel vertical migrations of low-trophic level organisms. At high latitudes, the long winter nights can provide foraging opportunities for marine predators targeting vertically migrating prey closer to the surface at night. However, there is limited documentation of such diel patterns in marine predators under extreme light regimes. To address this, we recorded the diving behavior of 17 harbour porpoises just south of the Arctic circle in West Greenland, from summer to winter. Unlike classical diel vertical migration, the porpoises dove 24–37% deeper at night and the frequency of deep dives (> 100 m) increased tenfold as they entered the darkest months. The daily mean depth was negatively correlated with daylength, suggesting an increased diving activity when approaching the polar night. Our findings suggest a light-mediated strategy in which harbour porpoises would either target (i) benthic prey, (ii) pelagic prey migrating seasonally towards the seafloor, or (iii) vertically migrating prey that may be otherwise inaccessible in deeper waters at night, therefore maximizing feeding activity during extended periods of darkness. Extreme light regimes observed at high latitudes are therefore critical in structuring pelagic communities and food webs.

Spatial prey availability and pulsed reproductive tactics: Encounter risk in a canid-ungulate system.

Predation risk is a function of spatiotemporal overlap between predator and prey, as well as behavioural responses during encounters. Dynamic factors (e.g. group size, prey availability and animal movement or state) affect risk, but rarely are integrated in risk assessments. Our work targets a system where predation risk is fundamentally linked to temporal patterns in prey abundance and behaviour. For neonatal ungulate prey, risk is defined within a short temporal window during which the pulse in parturition, increasing movement capacity with age and antipredation tactics have the potential to mediate risk. In our coyote-mule deer (Canis latrans-Odocoileus hemionus) system, leveraging GPS data collected from both predator and prey, we tested expectations of shared enemy and reproductive risk hypotheses. We asked two questions regarding risk: (A) How does primary and alternative prey habitat, predator and prey activity, and reproductive tactics (e.g. birth synchrony and maternal defence) influence the vulnerability of a neonate encountering a predator? (B) How do the same factors affect behaviour by predators relative to the time before and after an encounter? Despite increased selection for mule deer and intensified search behaviour by coyotes during the peak in mule deer parturition, mule deer were afforded protection from predation via predator swamping, experiencing reduced per-capita encounter risk when most neonates were born. Mule deer occupying rabbit habitat (Sylvilagus spp.; coyote's primary prey) experienced the greatest risk of encounter but the availability of rabbit habitat did not affect predator behaviour during encounters. Encounter risk increased in areas with greater availability of mule deer habitat: coyotes shifted their behaviour relative to deer habitat, and the pulse in mule deer parturition and movement of neonatal deer during encounters elicited increased speed and tortuosity by coyotes. In addition to the spatial distribution of prey, temporal patterns in prey availability and animal behavioural state were fundamental in defining risk. Our work reveals the nuanced consequences of pulsed availability on predation risk for alternative prey, whereby responses by predators to sudden resource availability, the lasting effects of diversionary prey and inherent antipredation tactics ultimately dictate risk.

New insights into predator-prey dynamics: First evidence of a leopard cat hunting coypus.

We present the first documented evidence of interactions between the leopard cat (Prionailurus bengalensis euptilurus) and the invasive coypu (Myocastor coypus) in South Korea, captured through camera traps in Hwapocheon wetland park from May 2015 to April 2017. Two interactions were recorded: one showing a leopard cat carrying a carcass of sub-adult coypu and the other a 4-min sequence of predation and defense between two species. The observed interactions indicate active predatory behavior by the leopard cat against coypus and cooperative defense by coypus. These findings shed new light on predator-prey dynamics, highlighting the leopard cat's potential role as a predator of coypus and coypus' defensive abilities. Understanding these relationships could facilitate more effective management of invasive species and offer broader implications for ecosystem dynamics and conservation strategies.

Conspecific density drives sex-specific spatial wintertime distribution and hoarding behaviour of an avian predator

Most studies on intraspecific competition, i.e., competition among individuals of the same species, have been conducted during the breeding season. Yet, at northern latitudes, intraspecific competition is expected to be particularly strong under the harsh weather conditions of the non-breeding season with limited number of resources available per individual. We studied the food-hoarding behaviour of wintering Eurasian Pygmy Owls (Glaucidium passerinum) along with sex- and age-specific spatial distribution in relation to fluctuating main prey abundance (voles) and conspecific density using a 15-year dataset. In low vole abundance years, increasing conspecific density reduced the total prey number stored by an owl, suggesting high costs of exploitative competition. The distance between the stores of nearest neighbours was greater when both were females, suggesting that the spatial avoidance is driven by sex-specific competition. However, food stores of females had a larger amount of prey items, especially when the nearest neighbour was of the same sex. The number of stores hoarded by an owl increased with increasing conspecific densities. Distributing the prey items to multiple store-sites instead of one (shifting from larder-hoarding towards scatter-hoarding) can help to reduce the overall loss to potential pilfering when conspecific density is high. These results combined suggest that high conspecific density inflames sex-specific interference competition, rather than solely exploitative competition, and in turn drives the observed sex-specific spatial distribution. Adopting a sex-specific spatial distribution according to hoarding and aggressive behaviour can be a way to reduce the severity of intraspecific competition locally and could have cascading effects on the prey community.

Recommendations for the development of a carnivore viewing site at a colony of Cape fur seals (Arctocephalus pusillus pusillus) in southern Namibia

ABSTRACT This study examined the daily and monthly activity patterns of brown hyenas (Hyaena brunnea) and black-backed jackals (Canis mesomelas) at a Cape fur seal colony in southern Namibia, to provide recommendations for developing a sustainable wildlife viewing site. Observations conducted between November 2020 and October 2022 showed that the carnivores were most active between May and October, with jackals showing peak activity around sunrise and sunset, and brown hyenas mostly visiting around midday. The animals were more active during cloudy and cool weather. With the diurnal activity of carnivores and their predation behaviour on Cape fur seal (Arctocephalus pusillus pusillus) pups, the area has high ecotourism potential. Brown hyenas, however, are sensitive to human disturbance, such as moving vehicles and unknown sounds and smells. Therefore, limiting the number of visitors and creating a fixed viewpoint is recommended to minimise disturbance. This study provides valuable input on how ecotourism activities could be developed at a seal colony without compromising the sensitive wildlife there.

Myxococcus xanthus predation: an updated overview.

Bacterial predators are widely distributed across a variety of natural environments. Understanding predatory interactions is of great importance since they play a defining role in shaping microbial communities in habitats such as soils. Myxococcus xanthus is a soil-dwelling bacterial predator that can prey on Gram-positive and Gram-negative bacteria and even on eukaryotic microorganisms. This model organism has been studied for many decades for its unusual lifecycle, characterized by the formation of multicellular fruiting bodies filled with myxospores. However, less is known about its predatory behavior despite being an integral part of its lifecycle. Predation in M. xanthus is a multifactorial process that involves several mechanisms working synergistically, including motility systems to efficiently track and hunt prey, and a combination of short-range and contact-dependent mechanisms to achieve prey death and feed on them. In the short-range attack, M. xanthus is best known for the collective production of secondary metabolites and hydrolytic enzymes to kill prey and degrade cellular components. On the other hand, contact-dependent killing is a cell-to-cell process that relies on Tad-like and type III secretion systems. Furthermore, recent research has revealed that metals also play an important role during predation, either by inducing oxidative stress in the prey, or by competing for essential metals. In this paper, we review the current knowledge about M. xanthus predation, focusing on the different mechanisms used to hunt, kill, and feed on its prey, considering the most recent discoveries and the transcriptomic data available.

Dietary experience alters predatory behavior of two ladybird species on tomato potato psyllid.

The tomato potato psyllid, Bactericera cockerelli, is an invasive pest in Australia, which can cause severe economic loss in the production of Solanaceous crops. As an invasive pest, B. cockerelli may also modify biotic interactions in Australian agricultural and native ecosystems. Resident generalist predators in an area may have the ability to utilize invasive pest species as prey but this will depend on their specific predatory behavior. The extent to which generalist predators learn from their previous dietary experience (i.e., whether they have used a particular species as prey before) and how this impacts subsequent prey choice will influence predator and prey population dynamics after invasion. In this study, one nonnative resident ladybird, Hippodamia variegata, and one native ladybird, Coccinella transversalis, were investigated. Dietary experience with B. cockerelli as a prey species significantly increased preference for the psyllid in a short term (6 h) Petri dish study where a choice of prey was given. Greater suppression of B. cockerelli populations by experienced ladybirds was also observed on glasshouse grown tomato plants. This was presumably due to altered prey recognition by experience. The result of this study suggest the potential to improve the impact of biological control agents on invasive pests by providing early life experience consuming the target species. It may prove valuable for developing improved augmentative release strategies for ladybirds to manage specific insect pest species.

Predator behaviour is altered by climate warming effects rippling through food webs

Predator behaviour is altered by climate warming effects rippling through food webs

Schooling behavior in a generalist predator–prey system: exploring fear, refuge and cooperative strategies in a stochastic environment

Schooling behavior in a generalist predator–prey system: exploring fear, refuge and cooperative strategies in a stochastic environment

Sustained use of marine subsidies promotes niche expansion in a wild felid

The use of marine subsidies by terrestrial predators can facilitate substantial transfer of nutrients between marine and terrestrial ecosystems. Marine resource subsidies may have profound effects on predator ecology, influencing population and niche dynamics. Expanding niches of top consumers can impact ecosystem resilience and interspecific interactions, affecting predator-prey dynamics and competition. We investigate the occurrence, importance, and impact of marine resources on trophic ecology and niche dynamics in a highly generalist predator, the caracal (Caracal caracal), on the Cape Peninsula, South Africa. Caracals have flexible diets, feeding across a wide range of terrestrial and aquatic prey. We use carbon and nitrogen stable isotope analysis of fur samples (n = 75) to understand trophic position and niche shifts in coastal and inland foragers, as well as the implications of a diet rich in marine resources. We found significant differences in isotope signatures between these groups, with higher δ13C (P < 0.05) and δ15N values (P < 0.01) in coastal foragers. Isotope mixing models reveal that these elevated signatures were due to non-terrestrial food subsidies, where approximately a third of coastal foraging caracal diet comprised marine prey. The addition of marine prey species to diet increased both the trophic level and isotope niche size of coastal foraging caracals, with potential impacts on prey populations and competition. Our results suggest that marine prey are an important dietary resource for coastal foraging caracals, where seabirds, including two endangered species, are a major component of their diet. However, there are likely risks associated with these resource benefits, as routine consumption of seabirds is linked with higher pollutant burdens, particularly metals. Increased encounters between this terrestrial predator and seabirds may be a result of increased mainland colonies due to changes in habitat availability and the highly opportunistic and generalist foraging behaviour of a native predator.

Dynamical behaviors of a specialist predator–prey system in open advective heterogeneous environments

In this paper, we investigate the effect of dispersal and advection on the dynamics of a specialist predator–prey model. More precisely, we show that the linear stability of the semi-trivial steady state is determined by the dispersal rate, the mortality rate of the predator and the advection rate. We point out that compared to homogeneous intrinsic growth rate and carrying capacity, the case in this paper is more complicated. This work gives a investigation to an open problem proposed by Nie et al. in Nie et al. (2020) by considering a more general model, and then, can be seen as a further development of their work (Nie et al., 2020).

A trade-off in evolution: the adaptive landscape of spiders without venom glands.

Venom glands play a key role in the predation and defense strategies of almost all spider groups. However, the spider family Uloboridae lacks venom glands and has evolved an adaptive strategy: they excessively wrap their prey directly with spider silk instead of paralyzing it first with toxins. This shift in survival strategy is very fascinating, but the genetic underpinnings behind it are poorly understood. Spanning multiple spider groups, we conducted multiomics analyses on Octonoba sinensis and described the adaptive evolution of the Uloboridae family at the genome level. We observed the coding genes of myosin and twitchin in muscles are under positive selection, energy metabolism functions are enhanced, and gene families related to tracheal development and tissue mechanical strength are expanded or emerged, all of which are related to the unique anatomical structure and predatory behavior of spiders in the family Uloboridae. In addition, we also scanned the elements that are absent or under relaxed purifying selection, as well as toxin gene homologs in the genomes of 2 species in this family. The results show that the absence of regions and regions under relaxed selection in these spiders' genomes are concentrated in areas related to development and neurosystem. The search for toxin homologs reveals possible gene function shift between toxins and nontoxins and confirms that there are no reliable toxin genes in the genome of this group. This study demonstrates the trade-off between different predation strategies in spiders, using either chemical or physical strategy, and provides insights into the possible mechanism underlying this trade-off. Venomless spiders need to mobilize multiple developmental and metabolic pathways related to motor function and limb mechanical strength to cover the decline in adaptability caused by the absence of venom glands.