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Predator and prey traits are important determinants of the outcomes of trophic interactions. In turn, the outcomes of trophic interactions shape predator and prey trait evolution. How species' traits respond to selection from trophic interactions depends crucially on whether and how heritable species' traits are and their genetic correlations. Of the many traits influencing the outcomes of trophic interactions, body size and movement traits have emerged as key traits. Yet, how these traits shape and are shaped by trophic interactions is unclear, as few studies have simultaneously measured the impacts of these traits on the outcomes of trophic interactions, their heritability, and their correlations within the same system. We used outcrossed lines of the ciliate protist Paramecium caudatum from natural populations to examine variation in morphology and movement behaviour, the heritability of that variation, and its effects on Paramecium susceptibility to predation by the copepod Macrocyclops albidus. We found that the Paramecium lines exhibited heritable variation in body size and movement traits. In contrast to expectations from allometric relationships, body size and movement speed showed little covariance among clonal lines. The proportion of Paramecium consumed by copepods was positively associated with Paramecium body size and velocity but with an interaction such that greater velocities led to greater predation risk for large body‐sized paramecia but did not alter predation risk for smaller paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force operating independently on movement and body size and generating the strongest selection against large, high‐velocity paramecia. Our results illustrate how ecology and genetics can shape potential natural selection on prey traits through the outcomes of trophic interactions. Further simultaneous measures of predation outcomes, traits, and their quantitative genetics will provide insights into the evolutionary ecology of species interactions and their eco‐evolutionary consequences. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

We consider a diffusive Rosenzweig–MacArthur predator–prey model in the situation when the prey diffuses at a rate much smaller than that of the predator. In a certain parameter regime, the existence of fronts in the system is known: the underlying dynamical system in a singular limit is reduced to a scalar Fisher–KPP (Kolmogorov–Petrovski–Piskunov) equation and the fronts supported by the full system are small perturbations of the Fisher–KPP fronts. The existence proof is based on the application of the Geometric Singular Perturbation Theory with respect to two small parameters. This paper is focused on the stability of the fronts. We show that, for some parameter regime, the fronts are spectrally and asymptotically stable using energy estimates, exponential dichotomies, the Evans function calculation, and a technique that involves constructing unstable augmented bundles. The energy estimates provide bounds on the unstable spectrum which depend on the small parameters of the system; the bounds are inversely proportional to these parameters. We further improve these estimates by showing that the eigenvalue problem is a small perturbation of some limiting (as the modulus of the eigenvalue parameter goes to infinity) system and that the limiting system has exponential dichotomies. Persistence of the exponential dichotomies then leads to bounds uniform in the small parameters. The main novelty of this approach is related to the fact that the limit of the eigenvalue problem is not autonomous. We then use the concept of the unstable augmented bundles and by treating these as multiscale topological structures with respect to the same two small parameters consequently as in the existence proof, we show that the stability of the fronts is also governed by the scalar Fisher–KPP equation. Furthermore, we perform numerical computations of the Evans function to explicitly identify regions in the parameter space where the fronts are spectrally stable. [ABSTRACT FROM AUTHOR]

Intense disturbances such as hurricanes may drastically affect ecosystems, producing both acute and long-term changes along coastlines. By disrupting human activities (e.g., fishing), hurricanes can provide an opportunity to quantify the effects of these activities on coastal ecosystems. We performed predator-exclusion experiments on oyster reefs in 2016, one-year before a category-4 hurricane ("Harvey") and again in 2018 one-year post-hurricane where the storm made landfall. Additionally, we examined 8 years (2011–2018) of fisheries-independent data to gauge how fishing pressure and fish populations were affected by the storm in three locations that varied in storm impacts. In the month following Hurricane Harvey, fishing effort dropped by 90% in the area with wind and flooding damage, and predatory fish species commonly targeted by anglers were 300% more abundant than the year prior to the hurricane. The locations without damage to fishing infrastructure did not experience declines in fishing pressure or changes in fish abundance, regardless of flooding disturbance. Reef fish and invertebrate communities directly affected by the storm were significantly different after the hurricane and were ~ 30% more diverse. With low fishing pressure, sportfish CPUE were 1.7–6.9 × higher immediately after the hurricane. Intermediate consumers, such as crabs that prey on oysters, were 45% less abundant and 10% smaller. These results indicate that hurricanes can temporarily disrupt human-ecosystem linkages and reconstitute top-down control by sportfish in estuarine food webs. Disturbance events that interrupt or weaken those interactions may yield indirect ecological benefits and provide insights into the effects of human activities on food webs. [ABSTRACT FROM AUTHOR]

The Grand Portage Band of Lake Superior Chippewa manages for sustainable subsistence harvests of moose (mooz; Alces alces) and white‐tailed deer (waawaashkeshi; Odocoileus virginianus). Moose populations in northern Minnesota, USA, are declining, which may necessitate alterations to Indigenous subsistence practices. Moose and deer exhibit seasonal behaviors such as altered space use and movement strategies, to which gray wolves (ma'iingan; Canis lupus) and humans may adapt, resulting in seasonal mortality patterns. Identifying periods of increased moose and deer vulnerability is important for achieving tribal conservation objectives. We assessed seasonal cause‐specific mortality of adult moose (2010–2021) and deer (2016–2022) fitted with global positioning system collars on and near the Grand Portage Indian Reservation (Gichi Onigaming; GPIR) in Minnesota and hypothesized mortality risk would be influenced by species‐specific space use patterns and weather. We estimated survival rates and mortality risk using time‐to‐event models. We recorded 42 moose mortalities (17 health issues, 8 predations, 4 subsistence harvests, 13 unknown causes) and 49 deer mortalities (26 predations, 13 harvests, 4 other causes, 6 unknown causes). Mean annual moose survival was 83.2%, and mortality risk peaked during late winter (~25 April) and fall (~8 October). Mean annual deer survival was 48.0%, and mortality risk peaked during late winter (~25 March) and during their fall migration period (~11 November). Mortality timing coincided with transitions between space use states (i.e., periods of spatial stability), suggesting ungulates are at greater risk during these transitional periods, though movement strategy (i.e., resident vs. migratory) did not influence mortality risk. Further, increased winter severity corresponded with increased deer mortality. We observed similar temporal peaks in mortality risk when harvest mortalities were censored, suggesting our observed seasonal mortality peaks occur naturally despite harvest comprising most fall deer mortality. Our results can inform population models and harvest regulations by identifying periods of mortality risk on GPIR under Anishinaabe principles of seventh‐generation conservation planning. [ABSTRACT FROM AUTHOR]

Aim: Spatiotemporal variation in resource availability is a strong driver of animal distributions. In the northern hardwood and boreal forests of the northeastern United States, tree mast events provide resource pulses that drive the population dynamics of small mammals, including the American red squirrel (Tamiasciurus hudsonicus), a primary songbird nest predator. This study sought to determine whether mast availability ameliorates their abiotic limits, enabling red squirrel elevational distributions to temporarily expand and negatively impact high‐elevation songbirds. Location: Northeastern United States. Methods: We used two independent datasets to evaluate our hypotheses. First, we fit a dynamic occupancy model using data from camera trap surveys to evaluate red squirrel distributional responses to pulses in the tree mast. We also assessed population responses using systematic auditory surveys analysed with an open‐population binomial mixture model. Further, we used modelled red squirrel abundance in nest‐survival models to evaluate whether their abundance is correlated with the daily nest survival of three songbird species. Results: The tree mast provided a critical resource pulse that resulted in a two‐fold increase in the annual elevational distribution of red squirrels. The elevational distribution of red squirrels ranged from a minimum of ~450 m (range: 663–1145 m asl) following two consecutive years without a masting event to a maximum of over 1000 m (range: 443–1545 m asl) after a large mast event. The daily nest survival of three songbird species tended to decline with an increase in the abundance of red squirrels. Main Conclusions: Tree mast is a central biological phenomenon in many temperate and boreal forests. This study reveals how this resource pulse results in range changes in a small mammal that is both a seed and bird predator, as well as prey for many carnivores. Thus, understanding this phenomenon can inform the conservation and management of northern forests, including breeding songbirds. [ABSTRACT FROM AUTHOR]

Encounters between animals occur when animals are close in space and time. Encounters are important in many ecological processes including sociality, predation and disease transmission. Despite this, there is little theory regarding the spatial distribution of encounters and no formal framework to relate environmental characteristics to encounters. The probability of encounter could be estimated with resource selection functions (RSFs) by comparing locations where encounters occurred to available locations where they may have occurred, but this estimate is complicated by the hierarchical nature of habitat selection.We developed a method to relate resources to the relative probability of encounter based on a scale‐integrated habitat selection framework. This framework integrates habitat selection at multiple scales to obtain an appropriate estimate of availability for encounters. Using this approach, we related encounter probabilities to landscape resources. The RSFs describe habitat associations at four scales, home ranges within the study area, areas of overlap within home ranges, locations within areas of overlap, and encounters compared to other locations, which can be combined into a single scale‐integrated RSF. We apply this method to intraspecific encounter data from two species: white‐tailed deer (Odocoileus virginianus) and elk (Cervus elaphus) and interspecific encounter data from a two‐species system of caribou (Rangifer tarandus) and coyote (Canis latrans).Our method produced scale‐integrated RSFs that represented the relative probability of encounter. The predicted spatial distribution of encounters obtained based on this scale‐integrated approach produced distributions that more accurately predicted novel encounters than a naïve approach or any individual scale alone.Our results highlight the importance of accounting for the conditional nature of habitat selection in estimating the habitat associations of animal encounters as opposed to 'naïve' comparisons of encounter locations with general availability. This method has direct relevance for testing hypotheses about the relationship between habitat and social or predator–prey behaviour and generating spatial predictions of encounters. Such spatial predictions may be vital for understanding the distribution of encounters driving disease transmission, predation rates and other population and community‐level processes. [ABSTRACT FROM AUTHOR]

Ecosystem approaches to fisheries management are being explored worldwide, but few evaluations of multispecies harvest control rules (HCRs) exist. Our goal was to perform a simulation test of a suite of HCRs using an age-structured predator–prey model to represent the dynamics of a small pelagic fish, Atlantic menhaden (Brevoortia tyrannus), and its predator, striped bass (Morone saxatilis). We evaluated a suite of static and dynamic single and multispecies HCRs to estimate effects on stock performance metrics. No single HCR achieved ecosystem management objectives for both stocks given their current reference points, but HCRs that involved the "40–10 rule" for striped bass performed well across all predator performance metrics. The most influential factor determining performance of striped bass HCRs was striped bass fishing mortality, and relatively few HCRs achieved target SSB for Atlantic menhaden. Our study indicated that some HCRs recommended for forage fish management may not be effective in systems with generalist predators, and that ecosystem management objectives might be achievable by simultaneously adopting HCRs for both predator and prey stocks that complement one another. [ABSTRACT FROM AUTHOR]

A reaction–diffusion system governing the predator–prey interaction with specialist predator and herd behavior for prey is investigated. Linear stability of the interior equilibrium is studied, and conditions guaranteeing the occurrence of Turing instability, induced by cross‐diffusion, are found, with a full characterization of the Turing instability region in the parameter space. Numerical simulations on the obtained results are provided. [ABSTRACT FROM AUTHOR]

We build on previous research describing correlative links between changes in the abundance of the copepod Calanus finmarchicus , a foundational zooplankton species of the pelagic food web, and diminishing recruitment of young-of-year American lobster (Homarus americanus) to benthic nurseries in the Gulf of Maine. Using parallel 31-year time series of lobster larvae and zooplankton collected on the New Hampshire coast between 1988 and 2018, we investigated how changes in phenology of stage I larval lobster and their putative copepod prey, C. finmarchicus , affect their temporal overlap and potential to interact during the larval season. We found that over the time series both the lobster egg hatch and first appearance of larvae began earlier in the season, a trend significantly correlated with ocean warming. The last appearance of larvae in late summer has been delayed, however, thereby extending the larval season. Even with the longer larval lobster season, the C. finmarchicus season has increasingly been ending before the peak abundance of stage I lobster larvae. The net effect is a widening mismatch in phenology of the two species, an outcome consistent with the hypothesis that changes in abundance and phenology of C. finmarchicus have contributed to recent declines in lobster recruitment. [ABSTRACT FROM AUTHOR]

Dispersal is a life-history trait of fundamental importance in single- and multi-species systems. Several studies indicate its central role for antagonistic species interactions, modulating ecological and evolutionary processes, epidemiology, spatial dynamics, and patterns of local adaptation. Dispersal itself can evolve, but only recently theoretical and experimental research has recognized the profound implications of this second-order evolutionary process for antagonistic interactions, including host-parasite, host-parasitoid, and predator-prey. We therefore call for more detailed investigations of dispersal evolution and its impact on critical interaction traits, such as virulence and resistance, and the potential for eco-evolutionary feedbacks. Dispersal evolution modifies diverse spatial processes, such as range expansions or biological invasions of single species, but we are currently lacking a realistic vision for metacommunities. Focusing on antagonistic species interactions, we review existing theory of dispersal evolution between natural enemies, and explain how this might be relevant for classic themes in host-parasite evolutionary ecology, namely virulence evolution or local adaptation. Specifically, we highlight the importance of considering the simultaneous (co)evolution of dispersal and interaction traits. Linking such multi-trait evolution with reciprocal demographic and epidemiological feedbacks might change basic predictions about coevolutionary processes and spatial dynamics of interacting species. Future challenges concern the integration of system-specific disease ecology or spatial modifiers, such as spatial network structure or environmental heterogeneity. [ABSTRACT FROM AUTHOR]

The Western Pacific gastropod Rapana venosa (Valenciennes, 1846) is classified among the hundred most dangerous invasive species of the Black and Mediterranean seas. Moreover, it is recognized as a dangerous invader in a number of coastal water areas on both sides of the Atlantic Ocean that determines the relevance of the study of population characteristics and biocenotic relationships of the rapa whelk in the areas of its invasion. The analysis of a previously unexplored R. venosa population in the Donuzlav Bay (the Northwestern Crimea) of the Black Sea in 2020 showed as follows: in the occurrence of an abundant and diverse food base, the rapa whelk does not form mass aggregations and, consequently, does not significantly affect benthic biocenoses. This fact is also confirmed by the ratio of biomass of the predatory mollusc and its prey. R. venosa mean biomass in the study area was 3.8 g·m−2, and the mean biomass of its food objects (Bivalvia) was 162.8 g·m−2. The features of the population structure and biocenotic relationships of the rapa whelk in the Donuzlav Bay are considered and discussed for the first time. Direct underwater observations and indirect evidence indicate that the distribution of this invader is controlled by aboriginal predators, crabs. The main species limiting R. venosa abundance in the study area is the crab Carcinus aestuarii Nardo, 1847.

Information on how the trophic ecology of predators shapes their movement patterns and space-use is fundamental to understanding ecological processes across organisational levels. Despite this, studies combining spatial and trophic ecology to determine how prey preference and/or resource availability shape space use are lacking in marine predators as these can occur at low density and are often difficult to track over extended periods. Furthermore, many exhibit behavioural variability within species and among closely related, sympatric species adding further complexity. We applied a context-focused, multimethod approach to the understudied great hammerhead shark (Sphyrna mokarran) to test if movement and home ranges relate to prey preference and availability. Movement data from satellite and acoustic telemetry in Queensland, Australia, were combined with stable-isotope analysis, drone surveys, and videos of hunting behaviour. Limited dispersal, and small home ranges in S. mokarran were linked to trophic specialisation on stingray prey. Drone surveys and videos showed predation events on stingrays and demonstrated high, year-round availability of this prey in shallow, inshore habitats, which may allow the majority of S. mokarran to remain resident. This affinity for inshore habitats suggests that critical life-history requirements are performed over local or regional scales, although some larger movements were evident. These results were interpreted in comparison to the well-studied bull shark (Carcharhinus leucas), which showed reliance on pelagic food webs. Carcharhinus leucas had high individual variability in movement, with both large-scale migrations and residency. This could indicate that only some individuals are locally sustained on dynamic, pelagic food webs, while others undergo large-scale excursions over distant habitats. The specialised foraging of S. mokarran indicates they play an apex predator role in shallow, inshore habitats, potentially shaping space-use, and foraging behaviour of batoids. As inshore habitats are disproportionately affected by anthropogenic stressors, S. mokarran's trophic specialisation and limited demographic connectivity may make the species particularly vulnerable to anthropogenic threats. [ABSTRACT FROM AUTHOR]

Most herbivores must balance demands to meet nutritional requirements, maintain stable thermoregulation and avoid predation. Species‐specific predator and prey characteristics determine the ability of prey to avoid predation and the ability of predators to maximize hunting success. Using GPS collar data from African wild dogs, lions, impala, tsessebes, wildebeest and zebra in the Okavango Delta, Botswana, we studied proactive predation risk avoidance by herbivores. We considered predator activity level in relation to prey movement, predator and prey habitat selection, and preferential use of areas by prey. We compared herbivore behaviour to lion and wild dog activity patterns and determined the effect of seasonal resource availability and prey body mass on anti‐predator behaviour. Herbivore movement patterns were more strongly correlated with lion than wild dog activity. Habitat selection by predators was not activity level dependent and, while prey and predators differed to some extent in their habitat selection, there were also overlaps, probably caused by predators seeking habitats with high prey abundance. Areas favoured by lions were used by herbivores more when lions were less active, whereas wild dog activity level was not correlated with prey use. Prey body mass was not a strong predictor of the strength of proactive predation avoidance behaviour. Herbivores showed stronger anti‐predator behaviours during the rainy season when resources were abundant. Reducing movement when top predators are most active and avoiding areas with a high likelihood of predator use during the same periods appear to be common strategies to minimize predation risk. Such valuable insights into predator–prey dynamics are only possible when using similar data from multiple sympatric species of predator and prey, an approach that should become more prevalent given the ongoing integration of technological methods into ecological studies. [ABSTRACT FROM AUTHOR]

Conservation biocontrol, the regulation of crop pests by naturally occurring biocontrol agents (e.g., predators and parasitoids), is predominantly monitored throughout periods of primary crop growth when pests exert the most observable impact on yields. Pest‐focused agricultural biomonitoring often overlooks post‐harvest, winter and even early‐season biocontrol, despite the significant predator–pest interactions during these periods that profoundly affect pest abundance and, consequently, crop yields. Rapid advances in biomonitoring, particularly in the detection of predator–pest interactions that underpin biocontrol, provide an opportunity to reconsider how and when we monitor these interactions. Advances in agricultural biomonitoring must transcend methodological innovation and encompass conceptual changes in the monitoring of agricultural systems. Here, we assess existing evidence supporting the importance of periods beyond primary crop growth for biocontrol and how predator–pest interactions are likely to evolve during these periods, subsequently influencing pest population dynamics during the primary crop growth period. We advocate for a greater concerted effort to establish continuous monitoring of biocontrol interactions, particularly beyond primary crop growth periods in temperate climates. To facilitate this, we also summarise the methodological approaches that can make it possible and explore how extending sampling across the full annual cycle might impact the practicalities and outcomes of these approaches. Year‐round monitoring of biocontrol interactions, both in crops and adjacent semi‐natural habitats, will provide a previously intractable understanding of predator–pest dynamics, offering significant potential to enhance our ability to optimise and manipulate these systems. This would manifest in reduced crop yield losses, pest infestation rates and disease transmission, with concomitant long‐term financial, environmental and land‐use benefits. [ABSTRACT FROM AUTHOR]

In this paper, a predator–prey system with multiple anti-predator behaviors is developed and studied, where not only the prey may spread between patches but also the fear effect and counter-attack behavior of the prey are taken into account. First, the stability and existence of coexistence equilibria are presented. The unique positive equilibrium may be a saddle-node or a cusp of codimension 2. Then, various transversality conditions of bifurcations such as saddle-node bifurcation, transcritical bifurcation, Hopf bifurcation and Bogdanov–Takens bifurcation are obtained. Moreover, compared with a single strategy, the multiple anti-predator strategies are more beneficial to the persistence and the population density of prey. [ABSTRACT FROM AUTHOR]

In North America, white‐nose syndrome (WNS) has caused precipitous declines in hibernating bat populations, raising the question of whether the rapid loss of arthropodivorous bats may affect the abundance of their prey. During the summers of 2015–2018 (1 year after the arrival of WNS in Wisconsin, USA), we performed intensive arthropod black‐light trapping, ultrasonic acoustic monitoring, and emergence counts at 10 little brown (Myotis lucifugus) and big brown (Eptesicus fuscus) bat maternity roosts with paired control sites. For little brown bats, which are severely affected by WNS, roost counts declined by 95% over the four‐year period, compared to a 38% decline in big brown bat roost counts. Total arthropod abundance decreased by 49%, although decreases among common little brown bat prey were less severe. Our natural predator exclusion experiment supports existing evidence that bats can have measurable trophic impacts on arthropod communities, primarily via top‐down effects on common prey. [ABSTRACT FROM AUTHOR]

Predator–prey interactions are a fundamental part of community ecology, yet the relative importance of consumptive and nonconsumptive effects (NCEs) (defined as a risk‐induced response that alters prey fitness) has not been resolved. Theory suggests that the emergence and subsequent predominance of consumptive or NCEs depend on the given habitat's complexity as well as predator hunting mode and spatial domain sizes of both predator and prey, but their relative influence on the outcome of predator–prey interactions is unknown. We built agent‐based models in NetLogo to simulate predator–prey interactions for three hunting modes—sit‐and‐wait, sit‐and‐pursue, and active—while concurrently simulating large versus small spatial domain sizes for both predators and prey. We studied (1) how hunting mode and spatial domain size interact to influence the emergence of consumptive or NCEs and (2) how, when NCEs do dominate, hunting mode and spatial domain separately or additively determine prey shifts in time, space, and habitat use. Our results indicate consumptive effects only dominate for active predators when prey habitat domains overlap completely with the predator's spatial domain and when sit‐and‐wait and sit‐and‐pursue predators and their prey both have large spatial domains. Prey are most likely to survive when they shift their time but most frequently shift their habitat. Our paper helps to better understand the underlying mechanisms that drive consumptive or NCEs to be most dominant. [ABSTRACT FROM AUTHOR]

The study of foraging behaviour is crucial for understanding several ecological and adaptive processes, as well as for developing conservation measures. While extensive research has been completed on birds and mammals, few studies have been conducted on the learning capabilities of amphibians, particularly those pertaining to foraging behaviour. Amphibians may detect potential prey through distinct sensory systems including visual detection, chemoreception, and mechanoreception. In this study, we tested whether fire salamander larvae shift their prey recognition depending on the prey stimulus typology. We performed behavioural assays to better understand the roles of visual and chemical cues in prey recognition and how a continuative visual stimulus may change behavioural patterns. For this assessment, larvae from different habitats (cave and stream) were reared under laboratory conditions and fed while exposed to accompanying sensory stimuli. Their responses to visual and olfactory cues were measured before and after rearing. Both visual and chemical cues significantly affected the time of approach to the stimulus. The period of rearing significantly interacted with the time of approach for both cues. After rearing, when visual cues occurred, the time of approach was much lower than before rearing. These findings provide a basis for further studies on the role of plasticity in the predator–prey interactions of fire salamander larvae. [ABSTRACT FROM AUTHOR]

Kaniatarowanenneh (the St. Lawrence River) is the outflow of one of the world's largest freshwater ecosystems and its ecological health has implications for resource management. The population dynamics of an ecologically and economically important fish, the Wa hia hé:ta, Mohawk for yellow perch (Perca flavescens), are considered by including data that extend to the past century to redress temporal gaps in comparative literature. We found both a significant top-down effect from piscivorous fish as well as a significant bottom-up effect related to total phosphorus on yellow perch relative abundance in the Lake Ontario–Upper St. Lawrence system. Regarding the bottom-up effect, the current state of yellow perch reflects the population size prior to cultural eutrophication (pre-1940s/50s) likely responding to the re-oligotrophication of the system. These findings emphasize the importance of considering historical records in fish population dynamics research to incorporate shifting population baselines into fisheries management. The study also demonstrates the need for collaborative approaches that bring critical new insights and multivocality. [ABSTRACT FROM AUTHOR]

We formulate and analyze a general diffusive predator–prey system with predator maturation delay. Global asymptotic stability of the predator-free equilibrium and uniform persistence results are obtained under different conditions on model parameters. We then use Leray–Schauder degree theory to establish the existence of the spatial heterogeneous steady state. Moreover, we prove the global existence of nonconstant positive steady states bifurcated from the positive constant steady state. Taking the time delay as the bifurcation parameter, we conduct local and global Hopf bifurcation analysis and prove the boundedness of global Hopf branches. Rigorous analyses for global Hopf bifurcation and branches are challenging but important in understanding global transitions of dynamics. [ABSTRACT FROM AUTHOR]

Understanding and predicting population responses to climate change is a crucial challenge. A key component of population responses to climate change are cases in which focal biological rates (e.g., population growth rates) change in response to climate change due to non‐compensatory effects of changes in the underlying components (e.g., birth and death rates) determining the focal rates. We refer to these responses as non‐compensatory climate change effects. As differential responses of biological rates to climate change have been documented in a variety of systems and arise at multiple levels of organization within and across species, non‐compensatory effects may be nearly ubiquitous. Yet, how non‐compensatory climate change responses combine and scale to influence the demographics of populations is often unclear and requires mapping them to the birth and death rates underlying population change. We provide a flexible framework for incorporating non‐compensatory changes in upstream rates within and among species and mapping their consequences for additional downstream rates across scales to their eventual effects on population growth rates. Throughout, we provide specific examples and potential applications of the framework. We hope this framework helps to enhance our understanding of and unify research on population responses to climate change. [ABSTRACT FROM AUTHOR]

In this paper, a diffusive predator-prey model with nonlocal competition and prey refuge is considered. The influence of parameters on the existence, multiplicity and stability of nonhomogeneous steady-state solutions is studied. It is obtained that an unstable positive nonconstant steady state exists in the neighborhood of the positive constant steady state. Compared with the model without nonlocal competition, the model with nonlocal competition can generate Hopf-Hopf bifurcation under some conditions. Through the qualitative analysis, the normal form at the Hopf-Hopf bifurcation singularity is calculated to analyze the different dynamic properties exhibited by the model in different parameter regions. In order to illustrate the feasibility of the obtained results and the dependence of the dynamic behavior on the nonlocal competition, numerical simulations are carried out. Through the numerical simulations, it is further shown that under certain conditions, the nonlocal competition will lead to the stablly spatially non-homogeneous periodic solutions and stablly spatially non-homogeneous quasi-periodic solutions. [ABSTRACT FROM AUTHOR]

The black carp (Mylopharyngodon piceus) is a non-native molluscivore established in the Mississippi River Basin, USA. Given that it is not practical to directly measure predation risk for every mollusk species black carp may encounter in the Mississippi River Basin, investigating morphological traits that influence vulnerability can provide a basis for making predictions of predator–prey outcomes for a variety of prey types. We conducted laboratory experiments to quantify size-specific vulnerability of native and nonnative mollusk taxa to consumption by juvenile black carp. Mollusks tested represented a range of shell morphologies and included bladder snails (Physella sp.), liver elimia (Elimia livescens), Chinese mystery snails (Cipangopaludina chinensis), Asian clams (Corbicula fluminea), fingernail clams (Sphaerium sp.), and attached and unattached zebra mussels (Dreissena polymorpha). Thick-shelled Asian clams were vulnerable over a narrower size range compared to the similarly shaped, but thin-shelled fingernail clams, which were vulnerable at shell widths up to 80% of predator mouth gape. Unattached zebra mussels were highly vulnerable across a wide range of shell sizes, with 95% of unattached individuals crushed or consumed, while attached zebra mussels were vulnerable over a narrower range of sizes and had a 46% higher survival rate. All three snail taxa were vulnerable at sizes exceeding black carp mouth gape, with bladder snails especially vulnerable (100% of individuals consumed). Interspecific differences among mollusks tested suggest juvenile black carp are limited by crushing ability and the relative shell size of their prey. For gastropods, elongate, tightly coiled shells were less vulnerable than wider, loosely coiled shells. For bivalves, round shell shapes were less vulnerable than elongate forms, and firm attachment reduced vulnerability. Our study suggests that juvenile black carp are capable of consuming a wide variety of shelled prey and their functional limitations as predators may be predicted based on the features of mollusk shells. [ABSTRACT FROM AUTHOR]

The group augmentation hypothesis states that individuals gain benefits by increasing group size and is rarely studied because it often overlaps with other evolutionary mechanisms like reciprocity. When rescuing a fellow prey from death, the mere presence of that member in the group can yield different benefits that can be passive like risk dilution or active like delayed reciprocity. We were able to separate the effects of passive and active group augmentation benefits by experimentally manipulating the behaviour of prey (altruist vs. non-altruist) in a video game where the costs and benefits of altruism were easily measured. The game pits four players-prey that must acquire resources to survive, while avoiding getting captured by a fifth player-predator. We instructed half of the prey players to avoid rescuing other prey, and the other half to rescue when possible. Our data showed that increasing the frequency of altruistic prey in a group increased survival of all group members. Maintaining group size yielded passive benefits like improving resource acquisition and facilitating future rescues. These passive benefits had a higher impact on survival than the active benefits (e.g., being rescued in return through reciprocity). Thus, we were able to support the importance of passive benefits from anti-predator altruistic behaviour using a biologically relevant online video game. Significance statement: Altruism can generate different benefits at once. Moreover, these benefits, like reciprocity or group augmentation, are often intertwined so distinguishing them in empirical data is complex. We were able to measure different benefits related to altruism and its effect on group size, using data from a multiplayer video game where players could rescue each other from predation and elimination. Rescuing others was risky but was beneficial to the survival of all the other group members. Benefits from belonging in a larger group, facilitated resource acquisition and rescues, were the most important benefits of altruism in our system, whereas reciprocity, a largely studied mechanism, was very rare. Our study adds important evidence of a mechanism, group augmentation, that is often overlooked or ignored when studying the selection of anti-predatory cooperative behaviours. [ABSTRACT FROM AUTHOR]

This work examines a discrete Leslie–Gower predator–prey system with herd behavior, focusing on the influence of the slow–fast effect on predator dynamics. We analyze the presence and stability of fixed points, investigating period-doubling and Neimark–Sacker bifurcations at the positive fixed point. A hybrid control technique is implemented to successfully handle chaotic dynamics. Numerical simulations validate the theoretical findings, supporting our analysis. The parameter 휖 in the predator–prey system has a significant impact on system dynamics due to the slow–fast effect it represents. A stable positive fixed point signifies a lasting and balanced coexistence of predator and prey populations within a certain 휖 interval. Deviation from this range results in period-doubling and Neimark–Sacker bifurcations, increasing both unpredictability and instability in the system. [ABSTRACT FROM AUTHOR]

Allee effect in models in interacting species of predator prey system has great significance in ecological context. Allee effect plays crucial role in population dynamics in ecology, where it is the challenging fact that per capita population growth rate is positively dependent on the population density of a species. In this paper, we inspect the famous Hastings and Powell (HP) (Hastings and Powell 1991 Ecology 72 896–903) model incorporating component Allee effect on top predator's reproduction. We analyse the updated model with the help of both analytical and numerical phenomena. Considering cost of Allee effect, half-saturation constant of prey as the key parameters, the Hopf bifurcations are also analysed. The directions of Hopf bifurcations at the critical values of Allee parameter and half-saturation constant of prey are studied theoretically by using normal form theory introduced by Hassard et al (1981 Theory and Applications of Hopf Bifurcation vol 41 (CUP Archive)). The formulated model indicates that the system demonstrates chaotic, periodic and stable dynamics in the variation of key parameters. The chaos can be controlled for proper application of the large values of parameter used as the cost of Allee effect and also for small values of the parameter used as the half saturation constant of prey population. The results of this study are applicable in the field of marine and wild ecosystem dynamics. [ABSTRACT FROM AUTHOR]

In this paper, we consider a predator-prey diffusion model incorporating hunting cooperation and predator-taxis. Firstly, we establish the global existence of a classical solution for the model in any spatial dimension. Secondly, we analyze the stability/instability caused by predator-taxis, and we observe that predator-taxis play a key role in inducing stability changes. Specifically, if the positive equilibrium is stable for the corresponding reaction-diffusion model, the attractive predator-taxis can further stabilize the system, while the repulsive predator-taxis may lead to a change in spatial stability, if the positive equilibrium is unstable for the corresponding reaction-diffusion model, the attractive predator-taxis makes the model remain unstable, while the repulsive predator-taxis has a stabilizing effect. Finally, numerical simulations are employed to validate the obtained results. [ABSTRACT FROM AUTHOR]

The ability to detect and respond to the presence of predation risk is under intense selection, especially for small‐bodied fishes. Damselfishes (Pomacentridae) use auditory vocalizations during inter‐ and intrasexual interactions, but it is not known if they can use vocalizations in the context of predator–prey interactions. Here, we test if yellowtail damselfish, Chrysiptera parasema, can learn to associate the territorial vocalization of heterospecific humbug damselfish Dascyllus aruanus with predation risk. In conditioning trials yellowtail damselfish were presented with the territorial call of humbug damselfish while either blank water (control treatment) or chemical alarm cue derived from damaged skin of conspecific yellowtail damselfish was introduced. In conditioning trials, fish exposed to alarm cue exhibited increased activity and spent more time in the water column relative to fish that received the control treatment. After a single conditioning trial, conditioned fish were exposed again to the territorial call of humbug damselfish. Fish conditioned with the call + alarm cue showed increased activity and spent more time in the water column relative to fish that had been conditioned with the control treatment. These data indicate associative learning of an auditory stimulus with predation risk in a species that regularly uses auditory signalling in other contexts. Recordings of conditioning and test trials failed to detect any acoustic calls produced by test fish in response to the perception of predation risk. Thus, although yellowtail damselfish can associate risk with auditory stimuli, we found no evidence that they produce an alarm call. [ABSTRACT FROM AUTHOR]

Predator non‐consumptive effects (NCE) can alter prey foraging time and habitat use, potentially reducing fitness. Prey can mitigate NCEs by increasing vigilance, chewing‐vigilance synchronization, and spatiotemporal avoidance of predators. We quantified the relationship between Mexican wolf (Canis lupus baileyi) predation risk and elk (Cervus canadensis) behavior. We conducted behavioral observations on adult female elk and developed predation risk indices using GPS collar data from Mexican wolves, locations of elk killed by wolves, and landscape covariates. We compared a priori models to determine the best predictors of adult female behavior and multitasking. Metrics that quantified both spatial and temporal predation risk were the most predictive. Vigilance was positively associated with increased predation risk. The effect of predation risk on foraging and resting differed across diurnal periods. During midday when wolf activity was lower, the probability of foraging increased while resting decreased in high‐risk areas. During crepuscular periods when elk and wolves were most active, increased predation risk was associated with increased vigilance and slight decreases in foraging. Our results suggest elk are temporally avoiding predation risk from Mexican wolves by trading resting for foraging, a trade‐off often not evaluated in behavioral studies. Probability of multitasking depended on canopy openness and an interaction between maternal period and predation risk; multitasking decreased prior to parturition and increased post parturition in high‐risk areas. Openness was inversely related to multitasking. These results suggest adult female elk are altering the type of vigilance used depending on resource availability/quality, current energetic needs, and predation risk. Our results highlight potentially important, but often‐excluded behaviors and trade‐offs prey species may use to reduce the indirect effects of predation and contribute additional context to our understanding of predator–prey dynamics. [ABSTRACT FROM AUTHOR]

In this paper, we carry out some research on a predator–prey system with maturation delay, a stage structure for generalist predators and a Holling type-II functional response, which has already been proposed. First, for the delayed model, we obtain the conditions for the occurrence of stability switches of the positive equilibrium and possible Hopf bifurcation values owing to the growth of the value of the delay by applying the geometric criterion. It should be pointed out that when we suppose that the characteristic equation has a pair of imaginary roots λ = ± i ω (ω > 0) , we just need to consider i ω (ω > 0) due to the symmetry, which alleviates the computation requirements. Next, we investigate the nature of Hopf bifurcation. Finally, we conduct numerical simulations to verify the correctness of our findings. [ABSTRACT FROM AUTHOR]

In this paper, we consider the predator-prey system with density-dependent motilities and pursuit-evasion interaction under homogeneous Neumann boundary conditions. The main obstacle of analysis comes from the term produced by pursuit-evasion interaction. With the $ L^p $-estimate techniques and Moser iteration, we show that the system possesses a global bounded classical solution. Furthermore, with the aid of Lyapunov functional, we establish the asymptotic behavior of solutions to this system under appropriate parameter conditions. [ABSTRACT FROM AUTHOR]

Introduced predators have been implicated in the extinction or range reduction of many Australian species, potentially due to native wildlife exhibiting prey naivety. We used traps with predator faeces present, monitored by camera traps, to determine if Australian mammals responded to native and introduced predator faeces. The presence of either faeces did not influence the trap or camera captures of any species. Some Australian mammals may exhibit prey naivety and not react to introduced predators. Using camera traps, we assessed how native mammals reacted to predator faeces placed in front of the traps. Presence of predator faeces did not influence trap or camera captures. Photograph by Meg Edwards. [ABSTRACT FROM AUTHOR]

Background: Prey are more vulnerable during migration due to decreased familiarity with their surroundings and spatially concentrated movements. Predators may respond to increased prey vulnerability by shifting their ranges to match prey. Moose (Alces alces) and white-tailed deer (Odocoileus virginianus) are primary gray wolf (Canis lupus) prey and important subsistence species for Indigenous communities. We hypothesized wolves would increase use of ungulate migration corridors during migrations and predicted wolf distributions would overlap primary available prey. Methods: We examined seasonal gray wolf, moose, and white-tailed deer movements on and near the Grand Portage Indian Reservation, Minnesota, USA. We analyzed GPS collar data during 2012–2021 using Brownian bridge movement models (BBMM) in Migration Mapper and mechanistic range shift analysis (MRSA) to estimate individual- and population-level occurrence distributions and determine the status and timing of range shifts. We estimated proportional overlap of wolf distributions with moose and deer distributions and tested for differences among seasons, prey populations, and wolf sex and pack affiliations. Results: We identified a single migration corridor through which white-tailed deer synchronously departed in April and returned in October–November. Gray wolf distributions overlapped the deer migration corridor similarly year-round, but wolves altered within-range distributions seasonally corresponding to prey distributions. Seasonal wolf distributions had the greatest overlap with deer during fall migration (10 October–28 November) and greatest overlap with moose during summer (3 May–9 October). Conclusions: Gray wolves did not increase their use of the white-tailed deer migration corridor but altered distributions within their territories in response to seasonal prey distributions. Greater overlap of wolves and white-tailed deer in fall may be due to greater predation success facilitated by asynchronous deer migration movements. Greater summer overlap between wolves and moose may be linked to moose calf vulnerability, American beaver (Castor canadensis) co-occurrence, and reduced deer abundance associated with migration. Our results suggest increases in predation pressure on deer in fall and moose in summer, which can inform Indigenous conservation efforts. We observed seasonal plasticity of wolf distributions suggestive of prey switching; that wolves did not exhibit migratory coupling was likely due to spatial constraints resulting from territoriality. [ABSTRACT FROM AUTHOR]

We propose and study a predator-prey model with a Smith growth function and the addition predation term described by a Holling Type Ⅱ functional response in prey. This additive predation term can lead to Allee effects in prey population dynamics that can generate complicated dynamics in the corresponding predator-prey model. We provide a through analysis of the global dynamics of the proposed model, including the equilibrium stability, Hopf bifurcation and its directions, existence of a heteroclinic orbit loop and limit cycles. We show that when the predator-prey model exhibits Allee effects, Hopf bifurcation is either backward and supercritical or forward and subcritical. In the strong Allee effect case, the model has a heteroclinic orbit loop connecting two boundary saddle points. Our results show that the coexistence can be achieved by controlling the attack rate of other potential predators so that the model exhibits weak Allee effects or no Allee effect. Both the small additional predation rate and the large replacement rate of mass can improve the coexistence probability of two species. The main difference of dynamics between the model exhibiting weak Allee effect and no Allee effect lies in the pattern of coexistence: If no Allee effect, the coexistence can be a steady state while in the weak Allee case, the coexistence may be periodic. [ABSTRACT FROM AUTHOR]

The dynamics of a Lotka-Volterra system of predator-prey type with time-dependent diffusive is studied. First, the existence and uniquely of positively global solution, uniform boundedness, and extinction are investigated. The analytical investigation uses a C0-quasi semi-group approach. The stabilities of the positively homogeneous steady states of the system are analyzed. Further, a simple analysis of Turing instability and Hopf bifurcation due to diffusion is also discussed that is confirmed by the bifurcation diagram. [ABSTRACT FROM AUTHOR]

Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species’ latitudinal range is poorly understood. Here we used satellite tracking from 21 Northern Gannet Morus bassanus colonies (39% of colonies worldwide, supporting 73% of the global population) during chick-rearing to test how foraging trip characteristics (distance and duration) covary with colony size (138–60 953 breeding pairs) and latitude across 89% of their latitudinal range (46.81–71.23° N). Tracking data for 1118 individuals showed that foraging trip duration and maximum distance both increased with square-root colony size. Foraging effort also varied between years for the same colony, consistent with a link to environmental variability. Trip duration and maximum distance also decreased with latitude, after controlling for colony size. Our results are consistent with density-dependent reduction in prey availability influencing colony size and reveal reduced competition at the poleward range margin. This provides a mechanism for rapid population growth at northern colonies and, therefore, a poleward shift in response to environmental change. Further work is required to understand when and how colonial animals deplete nearby prey, along with the positive and negative effects of social foraging behaviour.

In nature, the vast majority of species live in ecosystems that are not isolated, and the same is true for predator-prey ecological systems. With this work, we extend a predator-prey model by considering the inclusion of an immigration term in both species. From a biological point of view, that allows us to achieve a more realistic model. We consider a system with a Holling type Ⅰ functional response and study its global dynamics, which allows to not only determine the behavior in a region of the plane $ \mathbb{R}^2 $, but also to control the orbits that either go or come to infinity. First, we study the local dynamics of the system, by analyzing the singular points and their stability, as well as the possible behavior of the limit cycles when they exist. By using the Poincaré compactification, we determine the global dynamics by studying the global phase portraits in the positive quadrant of the Poincaré disk, which is the region where the system is of interest from a biological point of view.

Abstract Background Measuring coastal-pelagic prey fields at scales relevant to the movements of marine predators is challenging due to the dynamic and ephemeral nature of these environments. Whale sharks (Rhincodon typus) are thought to aggregate in nearshore tropical waters due to seasonally enhanced foraging opportunities. This implies that the three-dimensional movements of these animals may be associated with bio-physical properties that enhance prey availability. To date, few studies have tested this hypothesis. Methods Here, we conducted ship-based acoustic surveys, net tows and water column profiling (salinity, temperature, chlorophyll fluorescence) to determine the volumetric density, distribution and community composition of mesozooplankton (predominantly euphausiids and copepods) and oceanographic properties of the water column in the vicinity of whale sharks that were tracked simultaneously using satellite-linked tags at Ningaloo Reef, Western Australia. Generalised linear mixed effect models were used to explore relationships between the 3-dimensional movement behaviours of tracked sharks and surrounding prey fields at a spatial scale of ~ 1 km. Results We identified prey density as a significant driver of horizontal space use, with sharks occupying areas along the reef edge where densities were highest. These areas were characterised by complex bathymetry such as reef gutters and pinnacles. Temperature and salinity profiles revealed a well-mixed water column above the height of the bathymetry (top 40 m of the water column). Regions of stronger stratification were associated with reef gutters and pinnacles that concentrated prey near the seabed, and entrained productivity at local scales (~ 1 km). We found no quantitative relationship between the depth use of sharks and vertical distributions of horizontally averaged prey density. Whale sharks repeatedly dove to depths where spatially averaged prey concentration was highest but did not extend the time spent at these depth layers. Conclusions Our work reveals previously unrecognized complexity in interactions between whale sharks and their zooplankton prey.

The objective of this study was to analyze the complex dynamics of a discrete-time predator-prey system by using the piecewise constant argument technique. The existence and stability of fixed points were examined. It was shown that the system experienced period-doubling (PD) and Neimark-Sacker (NS) bifurcations at the positive fixed point by using the center manifold and bifurcation theory. The management of the system's bifurcating and fluctuating behavior may be controlled via the use of feedback and hybrid control approaches. Both methods were effective in controlling bifurcation and chaos. Furthermore, we used numerical simulations to empirically validate our theoretical findings. The chaotic behaviors of the system were recognized through bifurcation diagrams and maximum Lyapunov exponent graphs. The stability of the positive fixed point within the optimal prey growth rate range $ A_1 < a < A_2 $ was highlighted by our observations. When the value of $ a $ falls below a certain threshold $ A_1 $, it becomes challenging to effectively sustain prey populations in the face of predation, thereby affecting the survival of predators. When the growth rate surpasses a specific threshold denoted as $ A_2 $, it initiates a phase of rapid expansion. Predators initially benefit from this phase because it supplies them with sufficient food. Subsequently, resource depletion could occur, potentially resulting in long-term consequences for populations of both the predator and prey. Therefore, a moderate amount of prey's growth rate was beneficial for both predator and prey populations.

This study explores the complex dynamics of the predator–prey interactions, with a specific emphasis on the influence of the Allee effect on the predator population. We examined the fundamental mathematical characteristics of the model under consideration, such as the positivity of the system and the boundedness of the solutions. We investigated the equilibrium points and analyzed their stability using the Jacobi and Lyapunov methods. A comprehensive examination was carried out on the geometric properties of the dynamical system to compute the five invariants of the KCC theory. In particular, the deviation curvature tensor and its eigenvalues are investigated to demonstrate the behavior of the system stability. We have also obtained the necessary and sufficient conditions for the given set of parameters of the system in order to have the Jacobi stability (instability) near the equilibrium point. To visualize the dynamical behavior of the predator–prey model with the Allee effect in the predator density, numerical simulations were conducted. The investigation encompasses an examination of the system's behavior from both geometric and numerical standpoints, with the objective of attaining a thorough comprehension using few examples. [ABSTRACT FROM AUTHOR]

Acoustic tags fitted with predation sensors, which trigger following ingestion by piscivorous predators, were used to compare direct predation rates during downstream migration (out‐migration) of potamodromous (freshwater) brown trout (Salmo trutta L.) parr from their natal river into a large freshwater lake system during spring and autumn. Thirty‐eight spring migrants were tagged across two study years (2021 and 2022) of which 13 individuals (34%) were predated. By contrast 40 autumn migrants were tagged (2020 and 2021) of which three individuals (7.5%) experienced predation. The overall predation loss rate for spring migrants was 0.342% day−1 and was 0.075% day−1 for autumn migrants. Most predation events during spring (77%) occurred within the lower river before tagged fish entered the lake, whilst no predation events were recorded within the river in the autumn. Predation events were significantly linked to tagging season (spring or autumn), with the probability of tags remaining untriggered (as a proxy for survival) being higher 93% (95% confidence interval [CI] [87%, 100%]) in autumn than in spring 66% (95% CI [53%, 83%]). The spring migration periods showed significantly lower river discharge (0.321 m3/s mean daily discharge, April 1 to May 31) to those measured during autumn (1.056 m3/s mean daily discharge, October 1 to November 30) (Mann–Whitney U‐test, U = 1149, p < 0.001). Lower flows, clearer water, and longer sojourn in the river may have contributed to greater predation losses in the spring relative to the autumn. [ABSTRACT FROM AUTHOR]

Predators often use deception to exploit sensory and cognitive biases in prey. In pollinating insects, these include preferences for conspicuous colours associated with flowers, which predators such as orb‐web spiders display as prey lures. Theory predicts that deceptive signal efficacy should covary with both their perceptual similarity and physical proximity to the resources—here, flowers—whose cues they are imitating. Here I used the colour‐polymorphic jewelled spider Gasteracantha fornicata to test this prediction. I first examined spiders' capture success in the field, and found their visual resemblance and physical proximity to flowers interacted to mediate capture rates, with colour‐similarity becoming increasingly important as the distance between spiders and flowers decreased. I then replicated this interaction experimentally. Spiders adjacent to colour‐matched flowers enjoyed heightened capture success relative to those with nearby but colour‐mismatched flowers. While spiders with flowers placed at a distance (irrespective of colour) recorded the fewest captures. These results support 'neighbourhood' effects in aggressive deception as receivers' vulnerability to exploitation is mediated by the local signalling community. More generally, they emphasise the importance of the broader information landscape in the ecology of communication, and suggest misinformation is most effective when physically and perceptually proximate to the truth. [ABSTRACT FROM AUTHOR]

In this paper the author investigates the following predator-prey model with prey-taxis and rotational flux terms in a bounded domain with smooth boundary. He presents the global existence of generalized solutions to the model (*) in any dimension. [ABSTRACT FROM AUTHOR]

In this work, we study a class of diffusive predator-prey models with mutual interference among the predators while searching for food. Under Dirichlet boundary condition, by the fixed point index theory, we provide the necessary and sufficient conditions for the existence of coexistence states (i.e., stationary pattern). This is a strong contrast to the corresponding Neumann boundary problem, which exhibits bistability and admits no patterns. [ABSTRACT FROM AUTHOR]

The goal of this work is to explore basic qualitative dynamical properties of a two-species predator-prey chemotaxis system in a bounded domain $ \Omega\subset \mathbb{R}^N $ with smooth boundary and homogeneous Neumann boundary conditions. For the fully parabolic case, our main results in this direction assert the global boundedness of solutions without such extra conditions as in [11, 22]. In the corresponding parabolic-parabolic-elliptic case, we extend the global boundedness result of in [21] to dimensional $ N\geq 1 $. [ABSTRACT FROM AUTHOR]

Mathematical modelling of the evolution of the size-spectrum dynamics in aquatic ecosystems was discovered to be a powerful tool to have a deeper insight into impacts of human- and environmental driven changes on the marine ecosystem. In this article we propose to investigate such dynamics by formulating and investigating a suitable model. The underlying process for these dynamics is given by predation events, causing both growth and death of individuals, while keeping the total biomass within the ecosystem constant. The main governing equation investigated is deterministic and non-local of quadratic type, coming from binary interactions. Predation is assumed to strongly depend on the ratio between a predator and its prey, which is distributed around a preferred feeding preference value. Existence of solutions is shown in dependence of the choice of the feeding preference function as well as the choice of the search exponent, a constant influencing the average volume in water an individual has to search until it finds prey. The equation admits a trivial steady state representing a died out ecosystem, as well as—depending on the parameter-regime—steady states with gaps in the size spectrum, giving evidence to the well known cascade effect. The question of stability of these equilibria is considered, showing convergence to the trivial steady state in a certain range of parameters. These analytical observations are underlined by numerical simulations, with additionally exhibiting convergence to the non-trivial equilibrium for specific ranges of parameters. [ABSTRACT FROM AUTHOR]

In nature, the vast majority of species live in ecosystems that are not isolated, and the same is true for predator-prey ecological systems. With this work, we extend a predator-prey model by considering the inclusion of an immigration term in both species. From a biological point of view, that allows us to achieve a more realistic model. We consider a system with a Holling type Ⅰ functional response and study its global dynamics, which allows to not only determine the behavior in a region of the plane R 2 , but also to control the orbits that either go or come to infinity. First, we study the local dynamics of the system, by analyzing the singular points and their stability, as well as the possible behavior of the limit cycles when they exist. By using the Poincaré compactification, we determine the global dynamics by studying the global phase portraits in the positive quadrant of the Poincaré disk, which is the region where the system is of interest from a biological point of view. [ABSTRACT FROM AUTHOR]