scholarly journals The temporal selfish herd: predation risk while aggregations form

2010 ◽  
Vol 278 (1705) ◽  
pp. 605-612 ◽  
Author(s):  
Lesley J. Morrell ◽  
Graeme D. Ruxton ◽  
Richard James
Keyword(s):  
Selection Pressure ◽  
Alternative Strategies ◽  
Diverse Range ◽  
Predator Prey ◽  
Selfish Herd ◽  
Predator Attack ◽  
Movement Strategies ◽  
Movement Sequence ◽  
Animal Aggregation ◽  
Behavioural Diversity

The hypothesis of the selfish herd has been highly influential to our understanding of animal aggregation. Various movement strategies have been proposed by which individuals might aggregate to form a selfish herd as a defence against predation, but although the spatial benefits of these strategies have been extensively studied, little attention has been paid to the importance of predator attacks that occur while the aggregation is forming . We investigate the success of mutant aggregation strategies invading populations of individuals using alternative strategies and find that the invasion dynamics depend critically on the time scale of movement. If predation occurs early in the movement sequence, simpler strategies are likely to prevail. If predators attack later, more complex strategies invade. If there is variation in the timing of predator attacks (through variation within or between individual predators), we hypothesize that groups will consist of a mixture of strategies, dependent upon the distribution of predator attack times. Thus, behavioural diversity can evolve and be maintained in populations of animals experiencing a diverse range of predators differing solely in their attack behaviour. This has implications for our understanding of predator–prey dynamics, as the timing of predator attacks will exert selection pressure on prey behavioural responses, to which predators must respond.

scholarly journals Predator-induced flow disturbances alert prey, from the onset of an attack

2014 ◽  
Vol 281 (1790) ◽  
pp. 20141083 ◽  
Author(s):  
Jérôme Casas ◽  
Thomas Steinmann
Keyword(s):  
Prey Capture ◽  
Ground Effect ◽  
Just In Time ◽  
Soil Arthropods ◽  
Predator Prey ◽  
Flow Sensing ◽  
Predator Attack ◽  
Flow Disturbances ◽  
A Minor ◽  
High Degree

Many prey species, from soil arthropods to fish, perceive the approach of predators, allowing them to escape just in time. Thus, prey capture is as important to predators as prey finding. We extend an existing framework for understanding the conjoint trajectories of predator and prey after encounters, by estimating the ratio of predator attack and prey danger perception distances, and apply it to wolf spiders attacking wood crickets. Disturbances to air flow upstream from running spiders, which are sensed by crickets, were assessed by computational fluid dynamics with the finite-elements method for a much simplified spider model: body size, speed and ground effect were all required to obtain a faithful representation of the aerodynamic signature of the spider, with the legs making only a minor contribution. The relationship between attack speed and the maximal distance at which the cricket can perceive the danger is parabolic; it splits the space defined by these two variables into regions differing in their values for this ratio. For this biological interaction, the ratio is no greater than one, implying immediate perception of the danger, from the onset of attack. Particular attention should be paid to the ecomechanical aspects of interactions with such small ratio, because of the high degree of bidirectional coupling of the behaviour of the two protagonists. This conclusion applies to several other predator–prey systems with sensory ecologies based on flow sensing, in air and water.

scholarly journals Sharks shape the geometry of a selfish seal herd: experimental evidence from seal decoys

2009 ◽  
Vol 6 (1) ◽  
pp. 48-50 ◽  
Author(s):  
Alta De Vos ◽  
M. Justin O'Riain
Keyword(s):  
Experimental Evidence ◽  
Predation Risk ◽  
Prey Species ◽  
Group Formation ◽  
Predator Prey ◽  
Selfish Herd ◽  
Fur Seal ◽  
Cape Fur Seal ◽  
Shark Attacks ◽  
Proportional Reduction

Many animals respond to predation risk by forming groups. Evolutionary explanations for group formation in previously ungrouped, but loosely associated prey have typically evoked the selfish herd hypothesis. However, despite over 600 studies across a diverse array of taxa, the critical assumptions of this hypothesis have remained collectively untested, owing to several confounding problems in real predator–prey systems. To solve this, we manipulated the domains of danger of Cape fur seal ( Arctocephalus pusillus pusillus ) decoys to provide evidence that a selfish reduction in a seals' domain of danger results in a proportional reduction in its predation risk from ambush shark attacks. This behaviour confers a survival advantage to individual seals within a group and explains the evolution of selfish herds in a prey species. These findings empirically elevate Hamilton's selfish herd hypothesis to more than a ‘theoretical curiosity’.

scholarly journals Size-dependent functional response of Xenopus laevis feeding on mosquito larvae

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5813 ◽  
Author(s):  
Corey J. Thorp ◽  
Mhairi E. Alexander ◽  
James R. Vonesh ◽  
John Measey
Keyword(s):  
Xenopus Laevis ◽  
Functional Response ◽  
Handling Time ◽  
Mosquito Larvae ◽  
Agricultural Pests ◽  
Food Web Structure ◽  
Predator Prey ◽  
Predator Attack ◽  
Considerable Individual Variation ◽  
And Function

Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator–prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator–prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15–30 mm snout-vent length), medium (50–60 mm) and large (105–120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator’s potential impact on a prey population.

scholarly journals Size-dependent functional response of Xenopus laevis on mosquito larvae

2018 ◽  
Author(s):  
Corey J Thorp ◽  
Mhairi E Alexander ◽  
James R Vonesh ◽  
John Measey
Keyword(s):  
Body Size ◽  
Xenopus Laevis ◽  
Functional Response ◽  
Handling Time ◽  
Mosquito Larvae ◽  
Agricultural Pests ◽  
Food Web Structure ◽  
Predator Prey ◽  
Predator Attack ◽  
Considerable Individual Variation

Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator-prey interactions, like body size. This assumption may greatly oversimplify our understanding of within species functional diversity and undermine our ability to predict predator effects on prey. Here we examine the degree to which predator-prey interactions are functionally homogenous across a natural range of predator body size. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15-30mm snout-vent length), medium (50-60mm) and large (105-120mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments show that functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Both functional response and behavioural data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time respectively. That the functional response changed with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may be a misrepresentation of the predator’s potential impact on a prey population.

Adaptive Diversification Due to Predator-Prey Interactions

2011 ◽  
Author(s):  
Michael Doebeli
Keyword(s):  
Selection Pressure ◽  
Prey Species ◽  
Adaptive Dynamics ◽  
Two Dimensional ◽  
Predator Prey ◽  
Adaptive Diversification ◽  
Interacting Species ◽  
Volterra Models ◽  
Individual Based Models ◽  
Maintenance Of Diversity

This chapter discusses adaptive diversification due to predator–prey interactions. It has long been recognized that consumption, that is, predation, can not only exert strong selection pressure on the consumer, but also on the consumed species. However, predation has traditionally received much less attention than competition as a cause for the origin and maintenance of diversity. By using adaptive dynamics theory as well as individual-based models, the chapter then illustrates that adaptive diversification in prey species due to frequency-dependent predator–prey interactions is a theoretically plausible scenario. It also describes conditions for diversification due to predator–prey interactions in classical Lotka–Volterra models, which requires analysis of coevolutionary dynamics between two interacting species, and hence of adaptive dynamics in two-dimensional phenotype spaces.

Clay Caterpillar Whodunit: A Customizable Method for Studying Predator–Prey Interactions in the Field

2013 ◽  
Vol 75 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Rachel Curtis ◽  
Jeffrey A. Klemens ◽  
Salvatore J. Agosta ◽  
Andrew W. Bartlow ◽  
Steve Wood ◽  
...  
Keyword(s):  
Middle School ◽  
Community Ecology ◽  
Prey Species ◽  
College Level ◽  
Predator Prey ◽  
Important Concept ◽  
Predator Attack ◽  
Field Laboratory

Predator–prey dynamics are an important concept in ecology, often serving as an introduction to the field of community ecology. However, these dynamics are difficult for students to observe directly. We describe a methodology that employs model caterpillars made of clay to estimate rates of predator attack on a prey species. This approach can be implemented as a field laboratory in almost any natural or seminatural setting, and is designed to allow educators to pursue any number of student-generated hypotheses representing varying degrees of scientific sophistication ranging from middle school to college level.

scholarly journals Consequences of variation in predator attack for the evolution of the selfish herd

2014 ◽  
Vol 29 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Lesley J. Morrell ◽  
Lottie Greenwood ◽  
Graeme D. Ruxton
Keyword(s):  
Selfish Herd ◽  
Predator Attack

scholarly journals Stochastic dynamics of consumer-resource interactions

2021 ◽  
Author(s):  
Abhyudai Singh
Keyword(s):  
Attack Rate ◽  
Stochastic Dynamics ◽  
Reproduction Rate ◽  
Population Densities ◽  
Predator Prey ◽  
Density Dependent ◽  
Predator Prey Model ◽  
Predator Attack ◽  
Resource Interactions ◽  
Consumer Resource

AbstractThe interaction between a consumer (such as, a predator or a parasitoid) and a resource (such as, a prey or a host) forms an integral motif in ecological food webs, and has been modeled since the early 20th century starting from the seminal work of Lotka and Volterra. While the Lotka-Volterra predator-prey model predicts a neutrally stable equilibrium with oscillating population densities, a density-dependent predator attack rate is known to stabilize the equilibrium. Here, we consider a stochastic formulation of the Lotka-Volterra model where the prey’s reproduction rate is a random process, and the predator’s attack rate depends on both the prey and predator population densities. Analysis shows that increasing the sensitivity of the attack rate to the prey density attenuates the magnitude of stochastic fluctuations in the population densities. In contrast, these fluctuations vary non-monotonically with the sensitivity of the attack rate to the predator density with an optimal level of sensitivity minimizing the magnitude of fluctuations. Interestingly, our systematic study of the predator-prey correlations reveals distinct signatures depending on the form of the density-dependent attack rate. In summary, stochastic dynamics of nonlinear Lotka-Volterra models can be harnessed to infer density-dependent mechanisms regulating consumer-resource interactions. Moreover, these mechanisms can have contrasting consequences on population fluctuations, with predator-dependent attack rates amplifying stochasticity, while prey-dependent attack rates countering to buffer fluctuations.

scholarly journals Effect of elevated CO 2 and small boat noise on the kinematics of predator–prey interactions

2018 ◽  
Vol 285 (1875) ◽  
pp. 20172650 ◽  
Author(s):  
Mark I. McCormick ◽  
Sue-Ann Watson ◽  
Stephen D. Simpson ◽  
Bridie J. M. Allan
Keyword(s):  
Community Dynamics ◽  
Reef Fishes ◽  
Combined Effects ◽  
Predator Prey ◽  
Predator Attack ◽  
Perception Of Threat ◽  
Short Term Exposure ◽  
Multiplicative Effect ◽  
Key Drivers ◽  
Successful Capture

Oceans of the future are predicted to be more acidic and noisier, particularly along the productive coastal fringe. This study examined the independent and combined effects of short-term exposure to elevated CO 2 and boat noise on the predator–prey interactions of a pair of common coral reef fishes ( Pomacentrus wardi and its predator, Pseudochromis fuscus ). Successful capture of prey by predators was the same regardless of whether the pairs had been exposed to ambient control conditions, the addition of either playback of boat noise, elevated CO 2 (925 µatm) or both stressors simultaneously. The kinematics of the interaction were the same for all stressor combinations and differed from the controls. The effects of CO 2 or boat noise were the same, suggesting that their effects were substitutive in this situation. Prey reduced their perception of threat under both stressors individually and when combined, and this coincided with reduced predator attack distances and attack speeds. The lack of an additive or multiplicative effect when both stressors co-occurred was notable given the different mechanisms involved in sensory disruptions and highlights the importance of determining the combined effects of key drivers to aid in predicting community dynamics under future environmental scenarios.

scholarly journals Rosenzweig-Macaurther Model with Holling type II Predator Functional Response for Constant Delayed Migration

2019 ◽  
pp. 1-14
Author(s):  
Apima B. Samuel ◽  
Lawi O. George ◽  
Nthiiri J. Kagendo
Keyword(s):  
Stability Analysis ◽  
Functional Response ◽  
Food Source ◽  
Type Ii ◽  
Human Settlement ◽  
Natural Habitats ◽  
Predator Prey ◽  
Migration Rates ◽  
Predator Attack ◽  
Predator Prey Models

Predator-prey models describe the interaction between two species, the prey which serves as a food source to the predator. The migration of the prey for safety reasons after a predator attack and the predator in search of food, from a patch to another may not be instantaneous. In this paper, a Rosenzweig-MacAurther model with a Holling-type II predator functional response and time delay in the migration of both species is developed and analysed. Stability analysis of the system shows that depending on the prey growth and prey migration rates either both species go to extinction or co-exist. Numerical simulations show that a longer delay in the migration of the species leads makes the model to stabilize at a slower rate compared to when the delay is shorter. Relevant agencies likethe Kenya Wildlife Service should address factors that slow down migration of species, for example, destruction of natural habitats for human settlement and activities, which may cause delay in migration.

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