1. A group of 32 yellow baboons (Papio cynocephalus) in the Masai-Amboseli National Park, Kenya, caught and ate 45 vertebrate prey items during 2519.19 hours of observation. 2. Eighty percent of the prey items were mammals and the most frequently eaten species were African hares (Lepus capensis), vervet monkeys (Cercopithecus aethiops) and neonate gazelle (Cazella granti and G. thomsoni) in that order. The details of predatory behavior for each prey species are described. 3. Rates of predation were significantly higher during the long dry season than during other months of the year, although no correlation was found between total monthly rainfall and monthly rates of predation. A lognormal model however provided a good fit to the monthly rate of predation data suggesting that the rate of predation by Amboseli baboons was affected by several factors that acted multiplicatively with respect to each other and were themselves related to rainfall or dryness. 4. A mean of 2.3 individuals fed directly from the
Predatory behavior in wild chimpanzees and other primates has been well documented over the last 30 years. However, as it is an opportunistic behavior, conditions which may promote such behavior are left up to chance. Until now, predatory behavior among captive chimpanzees has been poorly documented. In this paper, we present five instances providing evidence of predatory behavior: four performed by isolated individuals and one carried out in cooperation. The evidence of group predation involved the chimpanzees adopting different roles as pursuers and ambushers. Prey was partially eaten in some cases, but not in the social episode. This study confirms that naturalistic environments allow chimpanzees to enhance species-typical behavioral patterns.
Food web complexity is thought to weaken the strength of terrestrial trophic cascades1,2,3 in which strong impacts of natural enemies on herbivores cascade to influence primary production indirectly4. Predator diversity can enhance food web complexity because predators may feed on each other and on shared prey5,6,7. In such cases, theory suggests that the impact of predation on herbivores relaxes and cascading effects on basal resources are dampened8,9. Despite this view, no empirical studies have explicitly investigated the role of predator diversity in mediating primary productivity in a natural terrestrial system10,11. Here we compare, in a coastal marsh community, impacts of arthropod predators on herbivores and plant productivity between a simple food web with a single predator species and a complex food web with a diverse predator assemblage. We show that enhancing predator diversity dampens enemy effects on herbivores and weakens trophic cascades. Consequently, changes in diversity at higher
This article describes a new technique used by ants ( Azteca cf. lanuginosa) in the Brazilian Cerrado to capture large mobile insects. Large numbers of ants position themselves along a leaf margin in
I have been twice on veterinary safaris to East Africa. There one will see lounging prides of lions, a short distance from grazing herds of zebra, a close relative of the horse.. As long as the lions are resting quietly, the zebra, always aware of the lions presence, do not flee.. But, if a lion arises and stretches, the zebra focuses on it. If the lion then casually moves away from the zebra, they go back to grazing.. If, however, the lion crouches, becomes motionless and stares at the zebra, they immediately prepare to flee.. I noted, long ago, that when stallions want to propel their range herd of mares and youngsters into flight, they assume a predatory stance. They lower their heads, crouch, and fix their eyes upon their "quarry". This motivates the herd into flight away from the predatory behavior even though that behavior is being displayed by a fellow prey animal - a horse.. Thus I learned that horses do not fear predators. They fear predatory behavior, the stalk and the charge. So ...
I have been twice on veterinary safaris to East Africa. There one will see lounging prides of lions, a short distance from grazing herds of zebra, a close relative of the horse.. As long as the lions are resting quietly, the zebra, always aware of the lions presence, do not flee.. But, if a lion arises and stretches, the zebra focuses on it. If the lion then casually moves away from the zebra, they go back to grazing.. If, however, the lion crouches, becomes motionless and stares at the zebra, they immediately prepare to flee.. I noted, long ago, that when stallions want to propel their range herd of mares and youngsters into flight, they assume a predatory stance. They lower their heads, crouch, and fix their eyes upon their "quarry". This motivates the herd into flight away from the predatory behavior even though that behavior is being displayed by a fellow prey animal - a horse.. Thus I learned that horses do not fear predators. They fear predatory behavior, the stalk and the charge. So ...
The use of natural organic extract instead of synthetic chemicals in harvesting wild fish and eliminating unwanted aquatic biota is popular in Nigeria. This research, th..
Play media Ambush predators or sit-and-wait predators are carnivorous animals or other organisms, such as some nematophagous fungi and carnivorous plants, that capture or trap prey by stealth or by strategy (typically not conscious strategy), rather than by speed or by strength. In animals, ambush predation is characterized by an animal scanning the environment from a concealed position and then rapidly executing a surprise attack. Animal ambush predators usually remain motionless (sometimes hidden) and wait for prey to come within ambush distance before pouncing. Ambush predators are often camouflaged, and may be solitary animals. This mode of predation may be less risky for the predator because lying-in-wait reduces exposure to its own predators. So long as the active predator cannot move faster than its prey, it has little advantage over the ambush predator; however, if the active predators velocity increases, its advantage increases sharply. Ambush predators use many intermediate ...
Predator-prey interactions: lecture content. Predator-prey interactions often dramatic, illustrated by snowshoe hare-lynx population fluctuations Simple Lotka-Volterra predator-prey model generates fluctuations of prey, predator Slideshow 4237377 by amish
In November 2006, American explorer and diver Scott Cassell led an expedition to the Gulf of California with the aim of filming a giant squid in its natural habitat. The team employed a novel filming method: using a Humboldt squid carrying a specially designed camera clipped to its fin. The camera-bearing squid caught on film what was claimed to be a giant squid, with an estimated length of 40 feet (12 m), engaging in predatory behavior.[49][50] The footage aired a year later on a History Channel program, MonsterQuest: Giant Squid Found.[50] Cassell subsequently distanced himself from this documentary, claiming that it contained multiple factual and scientific errors.[51] On 4 December 2006, an adult giant squid was caught on video near the Ogasawara Islands, 1,000 km (620 mi) south of Tokyo, by researchers from the National Science Museum of Japan led by Tsunemi Kubodera. It was a small female about 3.5 m (11 ft) long and weighing 50 kg (110 lb). The bait used by the scientists initially ...
While research on the neural basis for salticid behaviour is in its infancy, we do have some evidence for homologous processing compared with other taxa. For example, the orientation response of Servaea vestita is very selective to stimuli of certain sizes, with very small stimuli essentially ignored (despite being detected; D. B. Zurek and X.J.N., submitted). Furthermore, these responses are relatively velocity invariant, as found in the tectal neurons of frogs (see Ewert, 2004), although at optimal sizes (between 2 and 4 deg), there does appear to be an optimal not too fast speed (Zurek et al., 2010). This suggests that salticids, which have limited neural capacity in their minute brains, adopt mechanisms similar to those that have been found in several other groups, including toads and mantises (Ewert, 2004; Kral and Prete, 2004). The basic premise behind these mechanisms is that predators are able to recognise and respond with predatory behaviour to a particular class of objects - ...
University of Zurich. 252 million years ago the largest extinction event occurred at the end of the Permian age. It wiped out almost 90 percent of all life in water. So far researchers had assumed that the ecosystems gradually recovered from this catastrophe over a long stretch of eight to nine million years and that large predators at the uppermost end of the food chain were the last to reappear. A Swiss-American team of palaeontologists headed by Torsten Scheyer and Carlo Romano from the University of Zurich demonstrate in their new study that the food nets during the Early Triassic did not recover in stages. Large predators like, for instance, crocodile-like amphibians and later the precursors of the known plesiosaurs and ichthyosaurs went in search of prey in the oceans soon after the end of the mass extinction.. Large predators in on the action from the very start. Apex predators - large predators at the uppermost end of the food chain - are extremely important for the health and stability ...
In this paper, we argue that understanding marine ecosystem functioning requires a thorough appreciation of the role of intraguild predation to system dynamics. The theoretical predictions of intraguild predation models might explain some of the community features observed in marine ecosystems such as low diversity in upwelling and productive systems and species alternation in response to moderate external forcing. Finally, we argue that an ecosystem approach to fisheries requires that the size-structure of fish populations should be taken into account and that it is extremely important to account for the predators of early stages (eggs and larvae) to gain a thorough understanding of the key interactions between species ...
Taking inspiration from the biological world, in our work we are attempting to create and examine artificial predator-prey relationships using two LEGO robots. We do so to explore the possible adaptive value of emotion-like states for action selection in this context. However, we also aim to study and consider these concepts together at different levels of abstraction. For example, in terms of individual agents brain-body-environment interactions, as well as the (emergent) predator-prey relationships resulting from these. Here, we discuss some of the background concepts and motivations driving the design of our implementation and experiments. First, we explain why we think the predator-prey relationship is so interesting. Narrowing our focus to emotion-based architectures, this is followed by a review of existing literature, comparing different types and highlighting the novel aspects of our own. We conclude with our proposed contributions to the literature and thus, ultimately, the design and ...
Puppy and dog play, just like all social predatory animals consists of practice predatory behavior and practice fight behavior.. More relaxed body and face postures, as well as the relative restraint during bites, mark the difference between the play and the mature forms of aggression.. Play aggression is used to teach young working dogs techniques before transferring over to more realistic training.. Play aggression can also cause a nuisance and even injury to pet owners and children if not channeled and managed properly. Nonetheless, it is handled differently and should not be confused with any of the mature forms. ...
Stories of sexting, sex tapes, online dating gone wrong and cyberbullying are all over social media and the news. However, these stories only begin to scratch the surface of online - or technology-facilitated - gender-based violence (GBV). With a wide range of online predatory behaviors essentially falling under one label, how do we define it? How can we begin to tackle the problem if we cant grasp the full breadth of the problem?. The World Bank Group and the Sexual Violence Research Initiative (SVRI) has engaged the International Center for Research on Women (ICRW) to develop a way to measure technology-facilitated GBV on a global scale. To do this, our team is in the beginning stages of developing a conceptual framework. The reasoning behind this initiative is that, in order to tackle a problem like online violence, we must first get to the root of the problem by understanding the many ways online violence manifests itself. As researchers, defining the problem provides us with the insights ...
A delayed periodic predator-prey model with stage structure for predator is proposed. It is assumed that immature individuals and mature individuals of the predator are divided by a fixed age, and that immature predators do not have the ability to attack prey. Sufficient conditions are derived for the existence, uniqueness and global asymptotic stability of positive periodic solutions of the model. Numerical simulations are presented to illustrate the feasibility of our main results ...
Downloadable! Predator-prey relationships account for an important part of all interactions between species. In this paper we provide a microfoundation for such predator-prey relations in a food chain. Basic entities of our analysis are representative organisms of species modelled similar to economic households. With prices as indicators of scarcity, organisms are assumed to behave as if they maximize their net biomass subject to constraints which express the organismsâ€˜ risk of being preyed upon during predation. Like consumers, organisms face a â€˜budget constraintâ€˜ requiring their expenditure on prey biomass not to exceed their revenue from supplying own biomass. Short-run ecosystem equilibria are defined and derived. The net biomass acquired by the representative organism in the short term determines the positive or negative population growth. Moving short-run equilibria constitute the dynamics of the predator-prey relations that are characterized in numerical analysis. The population
According to the theory of predator-prey interactions, the relationship between herbivores and plants is cyclic.[40] When prey (plants) are numerous their predators (herbivores) increase in numbers, reducing the prey population, which in turn causes predator number to decline.[41] The prey population eventually recovers, starting a new cycle. This suggests that the population of the herbivore fluctuates around the carrying capacity of the food source, in this case the plant. Several factors play into these fluctuating populations and help stabilize predator-prey dynamics. For example, spatial heterogeneity is maintained, which means there will always be pockets of plants not found by herbivores. This stabilizing dynamic plays an especially important role for specialist herbivores that feed on one species of plant and prevents these specialists from wiping out their food source.[42] Prey defenses also help stabilize predator-prey dynamics, and for more information on these relationships see the ...
According to the theory of predator-prey interactions, the relationship between herbivores and plants is cyclic.[39] When prey (plants) are numerous their predators (herbivores) increase in numbers, reducing the prey population, which in turn causes predator number to decline.[40] The prey population eventually recovers, starting a new cycle. This suggests that the population of the herbivore fluctuates around the carrying capacity of the food source, in this case the plant.. Several factors play into these fluctuating populations and help stabilize predator-prey dynamics. For example, spatial heterogeneity is maintained, which means there will always be pockets of plants not found by herbivores. This stabilizing dynamic plays an especially important role for specialist herbivores that feed on one species of plant and prevents these specialists from wiping out their food source.[41] Prey defenses also help stabilize predator-prey dynamics, and for more information on these relationships see the ...
According to the theory of predator-prey interactions, the relationship between herbivores and plants is cyclic.[39] When prey (plants) are numerous their predators (herbivores) increase in numbers, reducing the prey population, which in turn causes predator number to decline.[40] The prey population eventually recovers, starting a new cycle. This suggests that the population of the herbivore fluctuates around the carrying capacity of the food source, in this case the plant.. Several factors play into these fluctuating populations and help stabilize predator-prey dynamics. For example, spatial heterogeneity is maintained, which means there will always be pockets of plants not found by herbivores. This stabilizing dynamic plays an especially important role for specialist herbivores that feed on one species of plant and prevents these specialists from wiping out their food source.[41] Prey defenses also help stabilize predator-prey dynamics, and for more information on these relationships see the ...
There is a paucity of ethological studies reporting the fleeing behaviour of prey under persistent attacks by their natural enemies, in contrast with the well-studied case of a single attack, followed by escape [14]. In fact, the number of predator-prey interactions with a rapid sequence of repeated attacks on the same prey by the same predator abound in nature, and older literature provides lengthy descriptions of such interactions, from pompilid wasps pursuing spiders to falcons attacking passerine prey (see Fabres description in [4] for the first case and [15] for the second case). These descriptions often lack crucial information to formalize them as repeated games, and are not quantified. In the following, we first report the findings of a few studies, conducted mainly with lizards [16] and grasshoppers [17] as prey and humans as predators. We then describe one biological interaction in more detail. We use this example to formalize the backbone of our theoretical study and describe in less ...
Our understanding of the dynamics of predator-prey systems has relied heavily on the use of models based on the standard Lotka-Volterra (LV) framework, dating back over 80 years. Although these models have been repeatedly analysed and refined since their initial inception, the way they describe the predators growth rate has received surprisingly little attention; typically it is simply assumed that the predators growth rate is linearly related to its ingestion rate according to a constant assimilation efficiency, e. However, for many consumers e is known to decrease at high prey densities. Models that ignore variable assimilation efficiencies overlook potentially important non-linearities, affecting the validity of predictions relating to conservation, invasion biology and pest control. Directly quantifying the relationship between e and prey abundance is, however, difficult. An alternative approach (the independent-response, IR, approach) is to not assume any direct link between the ...
Mosquito-borne diseases, such as the Zika virus, Malaria, Dengue fever and Yellow fever, could be controlled if Rio put a higher value on preserving wetlands, says Nicholas Locke, President of World Land Trusts Brazilian partner Reserva Ecológica de Guapiaçu (REGUA).. Health concerns have been escalating in the run up to the 2016 Rio Olympics, with athletes pulling out in response to warnings of water and mosquito-borne diseases. WLT asked REGUA president Nicholas Locke for comment.. "The recent public health scare in the form of Dengue and Zika outbreaks in Rio de Janeiro comes as a direct result of humans altering the natural world. In spite of creating one of largest planted urban parks in the world, the Tijuca National Park, the city of Rio virtually concreted and tarmacked all of its lowlands.". "As a result there is no habitat for the natural predators of mosquitoes, which breed successfully in accumulated run off water, thrive without predators and transmit these diseases." ...
Learning is important to consider in all manner of species interactions, including mutualism, competition, predation, and parasitism. In all cases, learning by one species in the interaction has the potential to shape the evolution of traits in the other species. For example, learning by predator species is thought to have played a role in the evolution of warning coloration in potential prey species. Warning coloration is coloration that serves to advertise the noxiousness of potential prey, to the mutual benefit of both prey and predator. It is typically highly conspicuous. One advantage of conspicuous coloration is that it is easier for the predator to detect from a distance. However, conspicuous coloration has two additional advantages. It is learned faster by predators and remembered longer, effects which should favor the evolution of conspicuous coloration.. A preys conspicuous coloration and a predators propensity to learn conspicuous colors could evolve in tandem, a prediction that ...
It is now clear that exposure to predators or predator cues can have sustained effects that extend to affecting birth and survival in free-living animals (Preisser, Bolnick & Benard 2005; Zanette et al. 2011). In this section, we describe those field studies that have (i) documented physiological stress effects, in the context of (ii) also demonstrating predator risk effects on demography. To our knowledge, only two experiments (Sheriff, Krebs & Boonstra 2009; Travers et al. 2010) have measured effects on stress physiology in relation to predator-induced changes in the birth rate - neither of which can be considered definitive; and we are not aware of any field experiment on free-living animals that has manipulated predator risk and demonstrated an effect on both (i) stress physiology and (ii) mortality not due to direct predation (see also Hawlena & Schmitz 2010b). Although the studies described in this section suggest that predator-induced stress can affect the demography of free-living ...
Many important questions in ecology and immunology involve dynamical systems with multiple stable states. We present a simple example of intra-guild predation which exhibits a variety of bi- and tri-stabilities. Intra-guild systems can be viewed as a coupling of two predator-prey systems by allowing one predator to additionally prey on the other. The two predators and the resource can coexist in equilibrium, in periodic solutions, and in chaotic solutions. One basic model of intra-guild predation is the system \begin{eqnarray*} R(t) &=&rR(t)\left(1-\frac{R(t)}{K}\right)-c_{1}R(t)N(t)-c_{2}R(t)P(t),\ N(t) &=&e_{1}c_{1}R(t-\tau)N(t-\tau)-c_{3}N(t)P(t)-m_{1}N(t),\ P(t) &=&e_{2}c_{2}R(t)P(t)+\epsilon_{3}c_{3}N(t)P(t)-m_{2}P(t). \end{eqnarray*} Here $R$ is a prey species, $N$ and $P$ are predator species, and $P$ additionally preys on $N$. In contrast with the simple predator-prey model, where delay tends to destabilize the dynamics, we show that the delay in this intra-guild predation model can ...
Discrimination between self and non-self is a prerequisite for any defence mechanism; in innate defence, this discrimination is often mediated by lectins recognizing non-self carbohydrate structures and so relies on an arsenal of host lectins with different specificities towards target organism carbohydrate structures. Recently, cytoplasmic lectins isolated from fungal fruiting bodies have been shown to play a role in the defence of multicellular fungi against predators and parasites. Here, we present a novel fruiting body lectin, CCL2, from the ink cap mushroom Coprinopsis cinerea. We demonstrate the toxicity of the lectin towards Caenorhabditis elegans and Drosophila melanogaster and present its NMR solution structure in complex with the trisaccharide, GlcNAcβ1,4[Fucα1,3]GlcNAc, to which it binds with high specificity and affinity in vitro. The structure reveals that the monomeric CCL2 adopts a β-trefoil fold and recognizes the trisaccharide by a single, topologically novel ...
We investigate the effects of different levels of predation pressure and rodent dispersal on the population dynamics of the African pest rodent Mastomys natalensis in maize fields in Tanzania.Three levels of predation risk were used in an experimental set-up: natural level (control), excluding predators by nets and attracting avian predators by nest boxes and perch poles. Because dispersal of the rodents could mask the predation pressure treatment effects, control and predator exclusion treatments were repeated with enclosed rodent populations.Population growth during the annual population rise period was faster in the absence of predators and peak population size was higher, but otherwise dynamics patterns were similar for populations where predators had access or were attracted, indicating that compensatory mechanisms operate when rodents are exposed to high levels of predation risk. Reducing dispersal of rodents removed the effect of predation on population growth and peak size, suggesting ...
This paper is concerned with a predator-prey system with a prey group defense and non-linear harvesting of the predator incorporating deterrence hypothesis for predators. Inclusion of predator...
Predation on planktonic larval stages is frequently a major source of mortality for the offspring of benthic marine invertebrates. Mortality rate likely varies with larval size and developmental stage, but few experiments have measured how these factors affect predation rates. I used experimental reductions in egg size to test how variation in larval size affects the likelihood of predation during planktonic development. Blastomeres of the sand dollar Dendraster excentricus were separated at the two-cell stage to produce half-sized zygotes. Larvae resulting from this manipulation were tested for their susceptibility to predation relative to whole-sized siblings at four ages. Individuals from each size class were simultaneously presented as prey items to five predators (crab zoeae, crab megalopae, chaetognaths, solitary tunicates, and postlarval fish) in the laboratory. Four predators consumed significantly more half-sized larvae than whole-sized larvae, but one predator type (postlarval fish) consumed
In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey ...
Paleontologists have worked very hard to establish a well-supported relationship between dinosaurs and birds and yet the researchers in the paper use the mammal predator-prey relationships of the African Serengeti ecosystem as a model for comparison. While we know that dinosaurs were probably warm-blooded to some extent, their metabolic systems are not fully understood and they may have achieved that warm-bloodedness in a manner unlike mammals and more comparable to birds, or a metabolic system between that of more primitive archosaurs, like crocodilians, and modern birds. As a result, it seems to me that modern predatory birds may be a better model for understanding the context of predator-prey relationships and inferring feeding behavior ...
The desert fox doesnt have many natural predators because it isnt easily caught by other animals. The primary predator of the desert fox is the desert eagle owl. Other potential predators include...
tropical weevils which have the elytra and the whole covering of the body so hard as to be a great annoyance to the entomologist, …, they cannot be pinned without first drilling a hole to receive the pin, and it is probable that all such find a protection in this excessive hardness.. The insects which others imitate always have a special protection, which leads them to be avoided as dangerous or uneatable by small insectivorous animals; some have a disgusting taste …; others have such a hard and stony covering that they cannot be crushed or digested;…. Alfred Russel Wallace, 1867. Predation is one of the most visible selective forces driving the ecology and evolution of organisms in nature (Abrams, 2000). Therefore, evolving effective anti-predator strategies is a significant component of adaptation for many prey species. Diverse defensive strategies have evolved in a range of specific stages in the encounters between predators and preys (Stevens, 2013). These anti-predator strategies ...
Abstract: The mechanisms of aposematism (unprofitability of prey combined with a conspicuous signal) have mainly been studied with reference to vertebrate predators, especially birds. We investigated whether dragonflies, Aeshna grandis, avoid attacking wasps, Vespula norwegica, which are an unprofitable group of prey for most predators. As a control we used flies that were painted either black or with yellow and black stripes. The dragonflies showed greater aversion to wasps than to flies. Black-and-yellow-striped flies were avoided more than black ones, suggesting that aposematic coloration on a harmless fly provides a selective advantage against invertebrate predators. There was no significant difference in reactions to black-painted and black-and-yellow wasps, indicating that, in addition to coloration, some other feature in wasps might deter predators. In further experiments we offered dragonflies artificial prey items in which the candidate warning signals (coloration, odour and shape) were ...
The description and analysis of chemical defense mechanisms across insects, mainly in lepidopteran and coleopteran herbivores, initiated the search for general trends in the taxonomic distribution and evolution of such mechanisms. Research using empirical and manipulative tests on predator-prey systems, computational modeling, and phylogeny-based approaches has identified sequential steps in the evolution of prey defensive traits as well as plant-insect interactions (e.g., [8, 14, 85-90]). However, nearly all such studies, even when they embrace multitrophic interactions at once, focus explicitly or implicitly on (dis)advantages as well as evolutionary sequences and consequences of visual prey signals. In this context, there is good evidence that the evolution of aposematism is accompanied by an increased diversification of lineages, as shown by paired sister-group comparisons in insects and other animal taxa [91]. Further, chemical adaptation (unpalatability) preceded morphological (warning ...
Habitat loss and fragmentation are among the greatest threats to biodiversity, and these threats can be exacerbated or alleviated by the presence of interacting species. The effect of habitat loss and fragmentation on predator-prey systems has received extensive theoretical attention, but empirical studies of these systems yield few clear patterns. I examined the influence of prey abundance and spatial distribution on the foraging ecology and spatial ecology of Masticophis flagellum (Coachwhip) using capture-mark-recapture and radio telemetry techniques. I also examined the influence of saurophagous snake abundance on the survival rate of Sceloporus woodi (Florida Scrub Lizard) populations. Masticophis flagellum positively selected lizard and mammal prey, but within these categories it consumed prey species in proportion to their availability. Masticophis flagellum was vagile and constrained its movements within large home ranges. At all spatial scales examined, M. flagellum strongly selected Florida
I work on the sensory and cognitive processes of animals in an evolutionary context. During my DPhil, I developed an interest in multimodal communication, where information is transferred betwen animals in more than one sensory modality. By studying the multimodal warning signals of toxic insect prey to their avian predators, I showed how cognitive systems can select for complex signalling. I also became interested in how animal signals evolve, leading to collaborations with Leena Lindstrom (Jyvaskyla) and Carel ten Cate (Leiden). More recently, my research has focussed on how predators make optimal foraging decisions when faced with a variety of palatable and toxic prey, and the implications of these decision-making processes on the evolution of prey defence strategies. Much of this work has been developed in collaboration with John Skelhorn (Newcastle) and Christina Halpin (Newcastle), and we are working with Andy Higginson (Bristol) to develop novel models for the evolution of prey defences ...
The book discusses the diversity of mechanisms by which prey can avoid or survive attacks by predators, both from ecological and evolutionary perspectives. There is a particular focus on sensory mechanisms by which prey can avoid being detected, avoid being identified, signal (perhaps sometimes dishonestly) to predators that they are defended or unpalatable. The book is divided into three sections. The first considers detection avoidance through, for example, background matching, disruptive patterning, countershading and counterillumination, or transparency and reflective silvering. The second section considers avoiding or surviving an attack if detection and identification by the predator has already taken place (i.e., secondary defences). The key mechanism of this section is aposematism: signals that warn the predator that a particular prey type is defended. One particularly interesting aspect of this is the sharing of the same signal by more than one defended species (the phenomenon of Mullerian
A delayed predator-prey system with Holling type II functional response and stage structure for both the predator and the prey is investigated. By analyzing the corresponding characteristic equations, the local stability of each of the feasible equilibria of the system is addressed and the existence of a Hopf bifurcation at the coexistence equilibrium is established. By means of persistence theory on infinite dimensional systems, it is proved that the system is permanent. By using Lyapunov functions and the LaSalle invariant principle, the global stability of each of the feasible equilibria of the model is discussed. Numerical simulations are carried out to illustrate the main theoretical results.
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The global decline of large carnivores makes efforts to understand their role in ecosystems vital. In addition to killing and consuming prey, large carnivores influence ecosystems by changing the behavior of their prey. Known as non-consumptive effects, these anti-predator behaviors are sometimes strong enough to affect prey nutrition and reproduction. Little research has been done on non-consumptive effects at the scale of large mammals apart from a few studies in the canid-dominated system of Yellowstone, yet theory suggests that ambush-hunting felids are more likely to produce strong non-consumptive effects ...
TY - JOUR. T1 - Effect of multiple delays on the dynamics of cannibalistic prey-predator system with disease in both populations. AU - Biswas, Santosh. AU - Samanta, Sudip. AU - Khan, Qamar J A. AU - Chattopadhyay, Joydev. PY - 2016. Y1 - 2016. UR - http://www.scopus.com/inward/record.url?scp=84996836092&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=84996836092&partnerID=8YFLogxK. U2 - 10.1142/S1793524517500498. DO - 10.1142/S1793524517500498. M3 - Article. AN - SCOPUS:84996836092. JO - International Journal of Biomathematics. JF - International Journal of Biomathematics. SN - 1793-5245. ER - ...
After SHTF, and you graduate to Hunter-Gatherer, here is something to keep in mind. In your hunting grounds, you most likely will not be the only predator hunting for food. This is a problem. To keep your hunting grounds to yourself, you are going to have to remove the other predators. In my area, Coyotes are the only other predator that we have. However other areas of the country have Bears, Big Cats, Wolves,…etc. to deal with. You MUST rid them by any means, and stay vigilant to keep them out. In the animal world, predators are always looking for territory that is prime. If you kill-off your competition, that doesnt mean in a month, another wont move in ...
A long-standing question in ecology is whether phenotypic plasticity, rather than selection per se, is responsible for phenotypic variation among populations. Phenotypic plasticity can, conceivably, either increase large-scale variation in phenotype along selection gradients or generate convergence in phenotype among genetically distinct populations exposed to a common selective pressure. Such patterns result from the ways in which reaction norms, which describe plasticity, manifest across environments. Theoretically, the expression of phenotypic plasticity can generate patterns of divergence or convergence in traits, and at multiple scales.. One of the most pervasive, well-studied selection pressures that might generate such patterns in phenotypic variation is predation risk. Prey species respond to predation risk by altering, often in an adaptive manner, aspects of their phenotype, including life history, morphology and behaviour [1,2]. Because the source (e.g. predator) and magnitude of ...
Theoretical considerations and curve fitting of data support the proposition that models for heterotrophic organisms are more realistic when individuals consist of two components: reserves and structure. Predators that prey on a population of such individuals can choose to assimilate the reserves or the structure of the prey, or both. As a consequence, the Holling type II description we use for predator-prey interaction has to be revised. In this article we study tri-trophic food chains with two-component populations in a chemostat. The influence of different degrees of assimilation of reserves and structure on the long-term dynamics of the food chain is studied with bifurcation analysis of the governing system of ODEs. The results presented in bifurcation diagrams show large quantitative effects. The modelling will start at the individual level. The two components of the prey are assimilated in parallel and the usable portions are added to a common storage pool, the reserves. The energy stored ...
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Pseudogenes and DNA-based diet analyses: a cautionary tale from a relatively well sampled predator-prey system - Volume 98 Issue 3 - G. Dunshea, N.B. Barros, R.S. Wells, N.J. Gales, M.A. Hindell, S.N. Jarman
Rectangular hyperbolic type 2 (RHt2; Michaelis-Menten or Monod-like) functions are commonly used to describe predation kinetics in plankton models, either alone or together with a prey selectivity algorithm deploying the same half-saturation constant for all prey types referenced to external prey biomass abundance. We present an analysis that indicates that such descriptions are liable to give outputs that are not plausible according to encounter theory. This is especially so for multi-prey type applications or where changes are made to the maximum feeding rate during a simulation. The RHt2 approach also gives no or limited potential for descriptions of events such as true de-selection of prey, effects of turbulence on encounters, or changes in grazer motility with satiation. We present an alternative, which carries minimal parameterization effort and computational cost, linking allometric algorithms relating prey abundance and encounter rates to a prey-selection function controlled by ...