scholarly journals Nutritional state reveals complex consequences of risk in a wild predator–prey community

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170757 ◽  
Author(s):  
Philip D. DeWitt ◽  
Matthew S. Schuler ◽  
Darcy R. Visscher ◽  
Richard P. Thiel
Keyword(s):  
Predation Risk ◽  
Nutritional State ◽  
Prey Population ◽  
Adult Survival ◽  
Predator Prey ◽  
Animal Populations ◽  
Risk Sensitive ◽  
Risk Sensitive Foraging ◽  
Insight Into ◽  
Prey Populations

Animal populations are regulated by the combined effects of top-down, bottom-up and abiotic processes. Ecologists have struggled to isolate these mechanisms because their effects on prey behaviour, nutrition, security and fitness are often interrelated. We monitored how forage, non-consumptive effects (NCEs), consumptive predation and climatic conditions influenced the demography and nutritional state of a wild prey population during predator recolonization. Combined measures of nutrition, survival and population growth reveal that predators imposed strong effects on the prey population through interacting non-consumptive and consumptive effects, and forage mechanisms. Predation was directly responsible for adult survival, while declining recruitment was attributed to predation risk-sensitive foraging, manifested in poor female nutrition and juvenile recruitment. Substituting nutritional state into the recruitment model through a shared term reveals that predation risk-sensitive foraging was nearly twice as influential as summer forage conditions. Our findings provide a novel, mechanistic insight into the complex means by which predators and forage conditions affect prey populations, and point to a need for more ecological studies that integrate behaviour, nutrition and demography. This line of inquiry can provide further insight into how NCEs interactively contribute to the dynamics of terrestrial prey populations; particularly, how predation risk-sensitive foraging has the potential to stabilize predator–prey coexistence.

To feed or flee: early life-history behavioural strategies of juvenile lake sturgeon (Acipenser fulvescens) during risk-sensitive foraging

2020 ◽  
Vol 98 (8) ◽  
pp. 541-550
Author(s):  
F. Bjornson ◽  
M. Earhart ◽  
W.G. Anderson
Keyword(s):  
Predation Risk ◽  
Early Life History ◽  
Lake Sturgeon ◽  
Whole Body ◽  
Acipenser Fulvescens ◽  
Reduced Body ◽  
Risk Sensitive ◽  
Partial Cover ◽  
Risk Sensitive Foraging ◽  
Behavioural Strategies

Balancing foraging opportunities with predation risk can promote complex behavioural strategies in juvenile fishes, particularly in northern temperate environments with short growing seasons. To test how predation experience may influence foraging effort and risk assessment of juvenile lake sturgeon (Acipenser fulvescens Rafinesque, 1817), flight response and substrate preference behavioural measurements were taken during critical life periods of early exogenous feeding (∼60 days post fertilization (dpf)) and pre-winter (∼160 dpf). Lake sturgeon were placed in arenas with partial cover and exposed white plastic bottom. Chemical alarm cue (AC) was introduced to predator naïve individuals in the presence or absence of food over the exposed portion of the arena to simulate risk sensitive foraging over diurnal and seasonal periods. The same protocol was run on predator-experienced individuals, which were classically conditioned to predator cue (PC) prior to the trials. Whole-body cortisol measures were also taken to determine the physiological response to predation experience. Results suggest a propensity to forage in spite of predation risk during the naïve ∼60 dpf trials and highlight context-specific anti-predator responses of naïve and experienced lake sturgeon. Elevated basal whole-body cortisol levels and reduced body condition (p < 0.05) were observed with increased predator experience.

Multi-species population models and evolutionarily stable strategies

1981 ◽  
Vol 18 (2) ◽  
pp. 507-513 ◽  
Author(s):  
W. G. S. Hines
Keyword(s):  
Matrix Model ◽  
Population Models ◽  
Prey Population ◽  
Population Composition ◽  
Evolutionarily Stable Strategies ◽  
Predator Prey ◽  
Trivial Equilibrium ◽  
Species Population ◽  
Evolutionarily Stable ◽  
Insight Into

The possibility that interspecific contest tactics might be able to stabilize two species predator-prey populations is investigated using a matrix model of the population. It is found that if the interspecific tactics have no influence on intraspecific encounters, the non-trivial equilibrium population composition is necessarily unstable. The result provides some insight into a reported instability of a predator-prey population with ‘stable' strategies.

scholarly journals The stabilizing effects of genetic diversity on predator-prey dynamics

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 43 ◽  
Author(s):  
Christopher F Steiner ◽  
Jordan Masse
Keyword(s):  
Genetic Diversity ◽  
Adaptive Capacity ◽  
Colony Size ◽  
Prey Abundance ◽  
Prey Population ◽  
General View ◽  
Population Abundance ◽  
Single Strain ◽  
Predator Prey ◽  
Prey Populations

Heterogeneity among prey in their susceptibility to predation is a potentially important stabilizer of predator-prey interactions, reducing the magnitude of population oscillations and enhancing total prey population abundance. When microevolutionary responses of prey populations occur at time scales comparable to population dynamics, adaptive responses in prey defense can, in theory, stabilize predator-prey dynamics and reduce top-down effects on prey abundance. While experiments have tested these predictions, less explored are the consequences of the evolution of prey phenotypes that can persist in both vulnerable and invulnerable classes. We tested this experimentally using a laboratory aquatic system composed of the rotifer Brachionus calyciflorus as a predator and the prey Synura petersenii, a colony-forming alga that exhibits genetic variation in its propensity to form colonies and colony size (larger colonies are a defense against predators). Prey populations of either low initial genetic diversity and low adaptive capacity or high initial genetic diversity and high adaptive capacity were crossed with predator presence and absence. Dynamics measured over the last 127 days of the 167-day experiment revealed no effects of initial prey genetic diversity on the average abundance or temporal variability of predator populations. However, genetic diversity and predator presence/absence interactively affected prey population abundance and stability; diversity of prey had no effects in the absence of predators but stabilized dynamics and increased total prey abundance in the presence of predators. The size structure of the genetically diverse prey populations diverged from single strain populations in the presence of predators, showing increases in colony size and in the relative abundance of cells found in colonies. Our work sheds light on the adaptive value of colony formation and supports the general view that genetic diversity and intraspecific trait variation of prey can play a vital role in the short-term dynamics and stability of planktonic predator-prey systems.

Multi-species population models and evolutionarily stable strategies

1981 ◽  
Vol 18 (02) ◽  
pp. 507-513 ◽  
Author(s):  
W. G. S. Hines
Keyword(s):  
Matrix Model ◽  
Population Models ◽  
Prey Population ◽  
Population Composition ◽  
Evolutionarily Stable Strategies ◽  
Predator Prey ◽  
Trivial Equilibrium ◽  
Species Population ◽  
Evolutionarily Stable ◽  
Insight Into

The possibility that interspecific contest tactics might be able to stabilize two species predator-prey populations is investigated using a matrix model of the population. It is found that if the interspecific tactics have no influence on intraspecific encounters, the non-trivial equilibrium population composition is necessarily unstable. The result provides some insight into a reported instability of a predator-prey population with ‘stable' strategies.

Risk sensitive foraging: an experimental study of a solitary marsupial.

2005 ◽  
Vol 27 (2) ◽  
pp. 231 ◽  
Author(s):  
LN Evans ◽  
MA Elgar ◽  
KA Handasyde
Keyword(s):  
Experimental Study ◽  
Early Detection ◽  
Predation Risk ◽  
Trade Off ◽  
Risk Sensitive ◽  
Risk Of Predation ◽  
Foraging Decisions ◽  
Foraging Site ◽  
Risk Sensitive Foraging

DETECTION and avoidance of predators are the principle strategies employed by prey to evade attack; by scanning their environment, prey individuals can reduce the likelihood of a predator approaching to within striking distance (Elgar 1989; Lima and Dill 1990). However, vigilance is often incompatible with foraging behaviours, and thus animals may be forced to trade-off the risk of predation against acquiring food. Consequently, the quality of a particular resource patch and its associated predation risk may influence the foraging decisions of animals (Werner et al. 1983; Newman and Caraco 1987; Heithaus and Dill 2002). Cover is an important feature of a foraging site because it can provide a hiding place to escape potential predators (Lazarus and Symonds 1992). Thus, animals may prefer foraging sites that are close to cover, or adjust their level of vigilance at different distances from cover in order to compensate for changes in the chance of early detection and escape (Elgar 1989; Lima and Dill 1990; Lima et al. 1985; Kramer and Bonenfant 1997).

scholarly journals Functional genomics study of Pseudomonas putida to determine traits associated with avoidance of a myxobacterial predator

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shukria Akbar ◽  
D. Cole Stevens
Keyword(s):  
Pseudomonas Putida ◽  
Bacterial Communities ◽  
Predator Avoidance ◽  
Phenotypic Diversity ◽  
Myxococcus Xanthus ◽  
Predator Prey ◽  
Mucoid Conversion ◽  
Small Colony ◽  
Predator Prey Models ◽  
Insight Into

AbstractPredation contributes to the structure and diversity of microbial communities. Predatory myxobacteria are ubiquitous to a variety of microbial habitats and capably consume a broad diversity of microbial prey. Predator–prey experiments utilizing myxobacteria have provided details into predatory mechanisms and features that facilitate consumption of prey. However, prey resistance to myxobacterial predation remains underexplored, and prey resistances have been observed exclusively from predator–prey experiments that included the model myxobacterium Myxococcus xanthus. Utilizing a predator–prey pairing that instead included the myxobacterium, Cystobacter ferrugineus, with Pseudomonas putida as prey, we observed surviving phenotypes capable of eluding predation. Comparative transcriptomics between P. putida unexposed to C. ferrugineus and the survivor phenotype suggested that increased expression of efflux pumps, genes associated with mucoid conversion, and various membrane features contribute to predator avoidance. Unique features observed from the survivor phenotype when compared to the parent P. putida include small colony variation, efflux-mediated antibiotic resistance, phenazine-1-carboxylic acid production, and increased mucoid conversion. These results demonstrate the utility of myxobacterial predator–prey models and provide insight into prey resistances in response to predatory stress that might contribute to the phenotypic diversity and structure of bacterial communities.

scholarly journals Be different to be better: the effect of personality on optimal foraging with incomplete knowledge

2021 ◽  
Author(s):  
Poppy M. Jeffries ◽  
Samantha C. Patrick ◽  
Jonathan R. Potts
Keyword(s):  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Partial Knowledge ◽  
Marginal Value ◽  
Animal Populations ◽  
Plausible Mechanism ◽  
Insight Into ◽  
Modelling Approach

AbstractMany animal populations include a diversity of personalities, and these personalities are often linked to foraging strategy. However, it is not always clear why populations should evolve to have this diversity. Indeed, optimal foraging theory typically seeks out a single optimal strategy for individuals in a population. So why do we, in fact, see a variety of strategies existing in a single population? Here, we aim to provide insight into this conundrum by modelling the particular case of foraging seabirds, that forage on patchy prey. These seabirds have only partial knowledge of their environment: they do not know exactly where the next patch will emerge, but they may have some understanding of which locations are more likely to lead to patch emergence than others. Many existing optimal foraging studies assume either complete knowledge (e.g. Marginal Value Theorem) or no knowledge (e.g. Lévy Flight Hypothesis), but here we construct a new modelling approach which incorporates partial knowledge. In our model, different foraging strategies are favoured by different birds along the bold-shy personality continuum, so we can assess the optimality of a personality type. We show that it is optimal to be shy (resp. bold) when living in a population of bold (resp. shy) birds. This observation gives a plausible mechanism behind the emergence of diverse personalities. We also show that environmental degradation is likely to favour shyer birds and cause a decrease in diversity of personality over time.

THE STABILITY OF THE CRITICAL POINTS OF THE GENERALIZED GAUSE TYPE PREDATOR-PREY FISHERY MODELS WITH PROPORTIONAL HARVESTING AND TIME DELAY

2021 ◽  
Vol 6 (2) ◽  
pp. 885
Author(s):  
Wan Natasha Wan Hussin ◽  
Rohana Embong ◽  
Che Noorlia Noor
Keyword(s):  
Time Delay ◽  
Response Function ◽  
Critical Points ◽  
Marine Ecosystem ◽  
Time Lag ◽  
Dynamical Problem ◽  
Delay Period ◽  
Prey Population ◽  
Predator Prey ◽  
Predator Response

In the marine ecosystem, the time delay or lag may occur in the predator response function, which measures the rate of capture of prey by a predator. This is because, when the growth of the prey population is null at the time delay period, the predator’s growth is affected by its population and prey population densities only after the time delay period. Therefore, the generalized Gause type predator-prey fishery models with a selective proportional harvesting rate of fish and time lag in the Holling type II predator response function are proposed to simulate and solve the population dynamical problem. From the mathematical analysis of the models, a certain dimension of time delays in the predator response or reaction function can change originally stable non-trivial critical points to unstable ones. This is due to the existence of the Hopf bifurcation that measures the critical values of the time lag, which will affect the stabilities of the non-trivial critical points of the models. Therefore, the effects of increasing and decreasing the values of selective proportional harvesting rate terms of prey and predator on the stabilities of the non-trivial critical points of the fishery models were analysed. Results have shown that, by increasing the values of the total proportion of prey and predator harvesting denoted by qx Ex and qy Ey respectively, within the range 0.3102 ≤ qx Ex ≤ 0.9984 and 0.5049 ≤ qy Ey ≤ 0.5363, the originally unstable non-trivial critical points of the fishery models can be stable.

Sign in / Sign up

Export Citation Format

Share Document