Predator-prey Research Articles

Dynamics of a prey–predator model with a strong Allee effect and Holling type-III ratio-dependent functional response

Dynamics of a prey–predator model with a strong Allee effect and Holling type-III ratio-dependent functional response

Effectiveness of the predatory mite Neoseiulus cucumeris on two-spotted spider mite and western flower thrips: A quantitative assessment.

The present study describes the feeding effects of Neoseiulus cucumeris Athias-Henriot (Acari: Phytoseiidae) on western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae). In addition, daily and total predation capacity, preference, and prey switching potential of this predator were studied on both pest species. WFT had a boosting effect on the biological parameters of N. cucumeris, primarily resulting in shorter developmental time, higher fecundity, and higher population growth potential than TSSM. Although immatures and males of N. cucumeris consumed significantly more TSSM than WFT, there was no significant difference in net predation rate, stable and finite predation rates of the predator between two prey species. We found an average of 10.58 and 7.93 TSSM and WFT are required to produce a single predator egg, respectively. WFT is preferred over TSSM by the predator. Negative switching behaviour was seen in N. cucumeris as it switched from the abundant prey to the rare prey. Both prey species were suitable for N. cucumeris, being able to develop successfully on them. The predator performed optimally on WFT compared with TSSM owing to its enhanced biological parameters as well as its preference, indicating that thrips are a more relevant resource than spider mites.

Temperature influences resource selection and predation risk tolerance in a climate generalist

ContextThermal conditions can influence animal behavior and predator–prey dynamics. Understanding the effects of temperature on animals and their interactions is of increasing importance given predictions for global warming.ObjectivesWe determined how temperature influenced avoidance of risky areas and habitat selection in a climate generalist, white-tailed deer (Odocoileus virginianus; hereafter “deer”), and how the effect varied between night and day in a system characterized by extreme heat and high predation risk from Florida panther (Puma concolor coryi).MethodsWe collected GPS locations of 224 (79 M, 145F) deer from June through September 2015–2018 in southwestern Florida, USA. We fit step-selection functions with interactions between ambient temperature and covariates including landcover and a spatial model of predation risk informed by panther kill sites.ResultsAvoidance of high-risk areas decreased with rising temperatures during night and day, indicating deer were less predation risk averse when balancing higher thermoregulatory costs. As temperatures increased during the day, deer increased avoidance of marshes and hardwood hammocks. However, temperature had weaker effects on habitat selection at night with only a moderate increase in selection of marshes with increasing temperatures.ConclusionsIn systems characterized by extreme heat, thermal conditions can have strong effects on animal behavior and species interactions. While climate generalists like deer have high tolerances to thermal stress, temperature still influenced predation risk tolerance and habitat selection of deer during both day and night periods. These responses are likely even stronger in species with narrower thermal tolerances (i.e., climate specialists). Thermal conditions are an important and potentially underappreciated driver of species interactions that is likely to become more significant with climate change.

Nonconsumptive effects of the predator Hippodamia convergens reduce probing behavior of Diaphorina citri on Citrus sinensis

AbstractNonconsumptive effects (NCEs) impact predator–prey interactions when the presence of a predator affects behavior, physiology, or population dynamics of the prey species without resulting in consumption. NCEs are critical to understanding ecological interactions broadly and in an applied manner, when addressing the efficacy of biological control within agroecosystems. In this study, we explore the impact of cues from the predator, Hippodamia convergens Guérin‐Méneville (Coleoptera: Coccinellidae), on the probing and feeding behavior of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citrus psyllid (ACP), which transmits the causal bacteria of Huanglongbing (HLB) disease of citrus (Rutaceae). Due to wide‐spread HLB incidence and insecticide resistance, it has become critical to better understand the activity of biological control agents within the HLB–ACP pathosystem. Utilizing electropenetrography (EPG), we investigated the feeding behavior of ACP exposed to the predator H. convergens or exposed to the chemical trails H. convergens produce while foraging. Overall, ACP detected H. convergens cues and responded by avoiding probing, although the extent of this response varied depending on the type of cue perceived. When H. convergens was present in the leaf but unable to reach the psyllid, ACP were slower to initiate probing and spent less time overall on probing and feeding from the xylem. In contrast, when exposed to H. convergens foraging cues without the beetle present, ACP initiated probing quicker than when the beetle was present and had a shorter total probing time compared to the control, with no other parameters being affected. Interestingly, the H. convergens chemical trail extracts, at two dosages, did not significantly influence ACP probing and feeding, except for a lower proportion of salivation and ingestion events into the phloem at the lower test dose. Our results suggest ACP exhibits avoidance behaviors in response to H. convergens cues, leading to a reduction in feeding, which suggests the maintenance of agroecosystem health through preservation of insect community diversity may be overlooked as an additive factor in vector management.

Predicting recoverability of collapsed food webs through perturbation and dimension reduction

Biodiversity collapse, driven by increasing environmental changes, poses significant threats to ecosystem stability and the provision of essential ecosystem services. Understanding the recoverability of collapsed food webs thus is crucial for devising effective conservation strategies. This study delves into the theoretical exploration of the recoverability of food webs from a collapsed state. Through simple tools like dimension reduction, propagation of species-specific perturbation, and dynamical simulations, we explore whether simple tri-trophic food webs can be recovered from a collapsed state. Our study examines in detail the topological features of food webs that could either facilitate or impede their recovery. We demonstrate that the recoverability of complex food webs can be predicted by using a simple dimension-reduced model, with certain structural factors that could constrain the full recovery of collapsed food webs. Furthermore, we found that such a simple dimension-reduced model can accurately capture the rate of recovery for complex collapsed food webs. In addition, dynamic simulations highlighted the significance of topological features such as connectance and the number of predator links in determining recoverability. Our dimension-reduced modeling framework offers insights into the feasibility of restoring entire complex predator–prey networks through species-specific interventions. This study contributes to a deeper understanding of ecosystem resilience and aids in the development of targeted conservation strategies.

Codimension-Two Bifurcation in a Class of a Discrete-Time Predator–Prey Interaction with Cannibalism

Codimension-Two Bifurcation in a Class of a Discrete-Time Predator–Prey Interaction with Cannibalism

A Game of Risk: Human Activities Shape Roe Deer Spatial Behavior in Presence of Wolves in the Southwestern Alps

In human-dominated landscapes, human activities shape prey spatial behavior, creating complex landscapes of risks. We investigated habitat selection of roe deer using resource selection functions in a human-dominated mountain system located in the southwestern Alps, characterized by a high presence of wolves and human disturbance. Our study aimed to assess how the interplay of hunting, presence of infrastructures, and recreational activities in the presence of wolves influenced roe deer spatial responses inside and outside a protected area. We documented that during the hunting period, roe deer increased selection of high-wolf-density areas, with the strongest effect observed during wild boar drive hunts, supporting the risk enhancement hypothesis, where avoiding one predator increases exposure to another, and highlighting the temporary yet significant impact of hunting on predator–prey dynamics. During the period of the wild boar drive hunt, roe deer also showed stronger selection for proximity to buildings, supporting the human shield hypothesis. Protected areas had an increased effect on roe deer avoidance of trails, where hiking and recreational activities are more concentrated. Our findings revealed the complex trade-offs that roe deer face in navigating multiple risks within human-modified landscapes, important for the development of effective conservation and human sustainability strategies.

Enhancing microbial predator–prey detection with network and trait-based analyses

BackgroundNetwork analyses are often applied to microbial communities using sequencing survey datasets. However, associations in such networks do not necessarily indicate actual biotic interactions, and even if they do, the nature of the interactions commonly remains unclear. While network analyses are valuable for generating hypotheses, the inferred hypotheses are rarely experimentally confirmed.ResultsWe employed cross-kingdom network analyses, applied trait-based functions to the microorganisms, and subsequently experimentally investigated the found putative predator–prey interactions to evaluate whether, and to what extent, correlations indicate actual predator–prey relationships. For this, we investigated algae and their protistan predators in biocrusts of three distinct polar regions, i.e., Svalbard, the Antarctic Peninsula, and Continental Antarctica. Network analyses using FlashWeave indicated that 89, 138, and 51 correlations occurred between predatory protists and algae, respectively. However, trait assignment revealed that only 4.7–9.3% of said correlations link predators to actually suitable prey. We further confirmed these results with HMSC modeling, which resulted in similar numbers of 7.5% and 4.8% linking predators to suitable prey for full co-occurrence and abundance models, respectively. The combination of network analyses and trait assignment increased confidence in the prediction of predator–prey interactions, as we show that 82% of all experimentally investigated correlations could be verified. Furthermore, we found that more vicious predators, i.e., predators with the highest growth rate in co-culture with their prey, exhibit higher stress and betweenness centrality — giving rise to the future possibility of determining important predators from their network statistics.ConclusionsOur results support the idea of using network analyses for inferring predator–prey interactions, but at the same time call for cautionary consideration of the results, by combining them with trait-based approaches to increase confidence in the prediction of biological interactions.FNXjBTWygxbKv-5R-GHg3pVideo

An Investigation of the Discrete-Time Model Subject to Immigration, Harvesting, and Allee Effect

This paper deals with the dynamic behaviors of a discrete-time fractional-order predator–prey model in the presence of both the Allee effect and immigration on the prey population and in the presence of harvesting on the predator population. The existence and uniqueness and parametric conditions for local asymptotic stability of fixed points of the discrete-time fractional-order model are studied. Moreover, using the center manifold theorem and bifurcation theory, it is shown that the considered model undergoes flip and Neimark–Sacker bifurcations in a small neighborhood of the interior fixed point. Then, the direction of bifurcation is calculated. A feedback controller is implemented in the proposed model to control chaos thanks to the emergence of the Neimark–Sacker bifurcation. Furthermore, numerical analysis confirms the theoretical analysis with the help of Matlab software.

Assembly processes inferred from eDNA surveys of a pond metacommunity are consistent with known species ecologies

Technological advances are enabling ecologists to conduct large‐scale and structured community surveys. However, it is unclear how best to extract information from these novel community data. We metabarcoded 48 vertebrate species from their eDNA in 320 ponds across England and applied the ‘internal structure' approach, which uses joint species distribution models (JSDMs) to explain compositions as the result of four metacommunity processes: environmental filtering, dispersal, species interactions, and stochasticity. We confirm that environmental filtering plays an important role in community assembly, and find that species' estimated environmental preferences are consistent with known ecologies. We also detect negative biotic covariances between fish and amphibians after controlling for divergent environmental preferences, consistent with predator–prey interactions (likely mediated by predator avoidance behaviour), and we detect high spatial autocorrelation for the palmate newt, consistent with its hypothesised relict distribution. Promisingly, ecologically and spatially distinctive sites are better explained by their environmental covariates and geographic locations, respectively, revealing sites where environmental filtering and dispersal limitation act more strongly. These results are consistent with the recent proposal that applying JSDMs to species distribution patterns can help reveal the relative importance of environmental filtering, dispersal limitation, and biotic interaction processes for individual sites and species. Our results also highlight the value of the modern interpretation of metacommunity ecology, which embraces the fact that assembly processes differ among species and sites. We discuss how novel community data allow for several study design improvements that will strengthen the inference of metacommunity assembly processes from observational data.

Stability and bifurcation analysis of a delayed stage-structured predator–prey model with fear, additional food, and cooperative behavior in both species

The stability of predator–prey interactions in ecosystems is influenced by both inherent species interactions and external factors. For instance, the presence of additional food, as an external factor, may affect the system. To further explore this, a stage-structured predator–prey model is constructed, incorporating the influences of fear and delay on prey-population growth, which provides additional food for immature predators and facilitates cooperative behavior between mature and immature predators. The analysis evaluates the positivity, boundedness, equilibrium points, local stability around each equilibrium point, and certain bifurcations of the system. Additionally, numerical simulations are provided to correspond with the results of the theoretical analysis. It is observed that an appropriate level of fear contributes positively to system stability. While cooperation among predators can benefit immature predators, it also has the potential to harm the overall system. The introduction of additional food complicates the system dynamics, although it benefits predators, it places prey at a disadvantage. Furthermore, we observe a correlation between the level of fear and the effects of additional food, as well as the capacity of additional food to mitigate the influence of delay.

From Sand to Bell: Novel Predation of Scyphozoans by the Giant Caribbean Sea Anemone Condylactis gigantea (Weinland, 1860) from the Western Atlantic

Predation is a fundamental ecological process that shapes marine ecosystem dynamics. This study reveals a novel predator–prey interaction between the giant Caribbean sea anemone Condylactis gigantea and the two jellyfish species Cassiopea sp. and Aurelia sp., challenging traditional understanding of sea anemone feeding habits. Observations from citizen science platforms and field recordings documented C. gigantea successfully capturing and consuming these gelatinous marine organisms. The research highlights the trophic plasticity of C. gigantea, demonstrating its ability to prey on larger gelatinous organisms beyond its traditionally known diet. This predation event represents a possible benthic–pelagic coupling mechanism and underscores the value of citizen science in capturing rare ecological interactions.

Spatiotemporal patterns in a predator–prey model with anti-predation behavior and fear effect

In this study, a predator–prey model incorporating prey’s fear effect and anti-predation behavior has been developed. The functional response takes the square root of the prey population and adds the predator’s loss term. We prove the existence of the system’s equilibrium point and derive the conditions for its local stability, as well as discuss how diffusion affects the system’s stability. Bifurcation analysis of the parameters reveals that the fear effect leads to a decrease in the predator population in the coexistence equilibrium. In addition, we apply the finite difference method and the finite element method to simulate the diffusion model in rectangles and irregular customized regions, respectively. The results demonstrate that the system can eventually reach a uniform stable state after experiencing oscillations and fluctuations at certain parameters and initial values.

Solution of Prey–Predator System by ADM

A prey-predator system with an abundance of nutrients is considered. Utilizing Adomian decomposition method to numerate and approximate the solution of that governing system. Providing many examples to obtain some numerical simulation solutions and plot the results for the prey and predator populations versus time.

Temperature and predator cues shape antipredator behavior in Amazonian tadpoles

Climate change has interfered with ecosystem stability, biodiversity and predator–prey interactions. Among amphibians, temperature variations may influence metabolism, sensory perception and behavior. We experimentally evaluated whether tadpoles of map treefrog, Boana geographica, reduce their activity and increase the use of refuge under different temperatures in response to chemical signals emitted by a predator, as an adaptive strategy to minimize the risk of predation. Tadpoles’ shelter use and feeding behavior was measured at temperatures from 28 to 36 °C using control (without predator cues) and treatment (predator cues) groups. Temperature influenced the shelter use of tadpoles when exposed to predator chemical cues. Significant differences were observed at lower temperatures and greater shelter use by tadpoles at higher temperatures. Food offering showed no significant difference in the control or treatment group. The increased use of shelter by tadpoles in response to chemical signals from predators and increased temperature highlights the adaptive capacity of organisms in the face of predation threats, highlighting the complexity of predator–prey interactions. This behavior highlights the role of environmental factors and sensory signals in shaping the survival strategies of aquatic ectotherms. Tadpoles minimize predation risk by increasing predator avoidance behavior in detecting chemical signals in the water.

The interplay of trophic interactions and game dynamics gives rise to life-history trade-offs, consistent personalities, and predator–prey and aggression power laws

The interplay of trophic interactions and game dynamics gives rise to life-history trade-offs, consistent personalities, and predator–prey and aggression power laws

The Existence and Stability of a Periodic Solution of a Nonautonomous Delayed Reaction–Diffusion Predator–Prey Model

In this study, we research a nonautonomous, three-species, delayed reaction–diffusion predator–prey model (RDPPM). Firstly, we derive sufficient conditions to guarantee the existence of a strictly positive, spatially homogeneous periodic solution (SHPS) for the delayed, nonautonomous RDPPM. These conditions are obtained using the comparison theorem for delayed differential equations and the fixed point theorem. Secondly, we present sufficient conditions to ensure the global asymptotic stability of the SHPS for the delayed, nonautonomous RDPPM. These conditions are established through the application of the upper and lower solution method (UALSM) for delayed parabolic partial differential equations (PDEs), along with Lyapunov stability theory. Finally, to demonstrate the practical application of our results, we numerically validate the proposed conditions using a 2-periodic, delayed, nonautonomous RDPPM.

Impact of nonlocal fear effect and mutual interference between predators in a diffusive predator–prey model

Impact of nonlocal fear effect and mutual interference between predators in a diffusive predator–prey model

A new dynamic distribution model for Antarctic krill reveals interactions with their environment, predators, and the commercial fishery in the south Scotia Sea region

AbstractThe management strategy for the Antarctic krill (Euphausia superba) fishery is being revised. A key aim is to spatially and temporally allocate catches in a manner that minimizes impacts to both the krill stock and dependent predators. This process requires spatial information on the distribution and abundance of krill, yet gaps exist for an important fishing area surrounding the South Orkney Islands in the south Scotia Sea. To fill this need, we create a dynamic distribution model for krill in this region. We used data from a spatially and temporally consistent acoustic survey (2011–2020) and year‐specific environmental covariates within a two‐part hurdle model. The model successfully captured observed spatial and temporal patterns in krill density. The covariates found to be most important included distance from shelf break, distance from summer sea ice extent, and salinity. The northern and eastern shelf edges of the South Orkney Islands were areas of consistently high krill density and displayed strong spatial overlap between intense fishing activity and foraging chinstrap penguins. High mean krill density was also linked to oceanographic features located within the Weddell Sea. Our data suggest that years in which these features were closer to the South Orkney shelf were also years of positive Southern Annular Mode and higher observed krill densities. Our findings highlight existing fishery–predator–prey overlap in the region and support the hypothesis that Weddell Sea oceanography may play a role in transporting krill into this region. These results will feed into the next phase of krill fisheries management assessment.

Nonequilibrium dynamics in a noise-induced predator–prey model

Nonequilibrium dynamics in a noise-induced predator–prey model