Death Of Prey Research Articles

Lotka-Volterra Model of Wastewater Treatment in Bioreactor System using 4th Order Runge-Kutta Method

Wastewater treatment is essential to preserve the ecosystem and to ensure water resources are uncontaminated. This paper presents the Lotka-Volterra model of nonlinear ordinary differential equations of the interaction between predator-prey and substrate. The dimensionless ordinary differential equations of the model are solved using the 4th Order Runge-Kutta method (RK4) in MATLAB®. This study discusses the behaviour parameters of predators, prey and substrate. The results are shown graphically for different values of each parameter. Hence, the biological reaction of clean water from the interaction of predator-prey and substrate in wastewater treatment is identified. The higher the concentration of prey, the faster the concentration of substrate reaches 0 with and without the natural death of prey. The clean water will be produced whenever the concentration of prey and the concentration of predator are in balance regardless of the natural death rate. Stability analysis using the Jacobian matrix at the equilibrium point is also performed to determine the stability of the system.

Long-term effects of abrupt environmental perturbations in model of group chase and escape with the presence of non-conservative processes

This paper examines the influence of environmental perturbations on dynamical regimes of model ecosystems. We study a stochastic lattice model describing the dynamics of a group chasing and escaping between predators and prey. The model includes smart pursuit (predators to prey) and evasion (prey from predators). Both species can affect their movement by visual perception within their finite sighting range. Non-conservative processes that change the number of individuals within the population, such as breeding and physiological dying, are implemented in the model. The model contains five parameters that control the breeding and physiological dying of predators and prey: the birth and two death rates of predators and two parameters characterizing the birth and death of prey. We study the response of our model of group chase and escape to sudden perturbations in values of parameters that characterize the non-conservative processes. Temporal dependencies of the number of predators and prey are compared for various perturbation events with different abrupt changes of probabilities affecting the non-conservative processes.

Impact of fear in a prey-predator system with herd behaviour

AbstractFear of predation plays an important role in the growth of a prey species in a prey-predator system. In this work, a two-species model is formulated where the prey species move in a herd to protect themselves and so it acts as a defense strategy. The birth rate of the prey here is affected due to fear of being attacked by predators and so, is considered as a decreasing function. Moreover, there is another fear term in the death rate of the prey population to emphasize the fact that the prey may die out of fear of predator too. But, in this model, the function characterizing the fear effect in the death of prey is assumed in such a way that it is increased only up to a certain level. The results show that the system performs oscillating behavior when the fear coefficient implemented in the birth of prey is considered in a small amount but it changes its dynamics through Hopf bifurcation and becomes stable for a higher value of the coefficient. Regulating the fear terms ultimately makes an impact on the growth of the predator population as the predator is taken as a specialist predator here. The increasing value of the fear terms (either implemented in birth or death of prey) decrease the count of the predator population with time. Also, the fear implemented in the birth rate of prey makes a higher impact on the growth of the predator population than in the case of the fear-induced death rate.

A Computer-Based Simulation Showing Balance of the Population of Predator and Prey and the Effects of Human Intervention

In this paper, a computer-based simulation of the predator-prey model has been proposed. The prey is a source of food for the predator, which is necessary for the prey’s survival. Various models, such as the Lotka-Volterra model and the cellular automata model, have been used to simulate predator and prey movement in a population. These methods have been discussed briefly. The limitations of both these methods have been highlighted. After discussing the limitations of both these methods, a novel computer-based simulation has been proposed to address the previous models’ limitations. Since this model takes into account a more realistic movement of predator and prey, it has been used to study the harmful effects of human intervention on the environment. In this simulation, the birth of predators and prey by mating, the death of predators and prey due to starvation, and the death of prey due to attacks from predators are taken into consideration. In the first case, there is no human intervention. In the next two cases, human intervention is taken into consideration. In one case, the proportion of predators in the population increases, and in the other case, the prey population increases. A comparison has been made between all three cases, and a study has been done showing how human intervention affects the population of predators and prey over a long time.

Causalities of war: The connection between type VI secretion system and microbiota.

Microbiota niches have space and/or nutrient restrictions, which has led to the coevolution of cooperation, specialisation, and competition within the population. Different animal and environmental niches contain defined resident microbiota that tend to be stable over time and offer protection against undesired intruders. Yet fluxes can occur, which alter the composition of a bacterial population. In humans, the microbiota are now considered a key contributor to maintenance of health and homeostasis, and its alteration leads to dysbiosis. The bacterial type VI secretion system (T6SS) transports proteins into the environment, directly into host cells or can function as an antibacterial weapon by killing surrounding competitors. Upon contact with neighbouring cells, the T6SS fires, delivering a payload of effector proteins. In the absence of an immunity protein, this results in growth inhibition or death of prey leading to a competitive advantage for the attacker. It is becoming apparent that the T6SS has a role in modulating and shaping the microbiota at multiple levels, which is the focus of this review. Discussed here is the T6SS, its role in competition, key examples of its effect upon the microbiota, and future avenues of research.

Sometimes hard to swallow: Attempted feeding on a porcupinefish results in death of both predator and prey

Predator-prey relationships are critical components of population dynamics across all ecosystems. Interactions between predators and dangerous prey are especially likely to result in a co-evolutionary arms race. To avoid predation, porcupinefishes (Diodontidae) present a suite of physical and chemical defences, including spines, inflation, and the potent neurotoxin, tetrodotoxin, which is concentrated in the internal organs. A failed predation attempt is described here on a longspined porcupinefish, Diodon holocanthus, by a benthopelagic predator, Carangoides fulvoguttatus, resulting in the death of both the predator and the prey.

Insecticidal bacteria isolated from predatory larvae of the antlion species Myrmeleon bore (Neuroptera: Myrmeleontidae)

Various bacterial species were isolated from the crop (digestive organ) of the antlion species Myrmeleon bore and tested for their insecticidal activity against caterpillars by injection. Sixty-eight isolates from the antlion crop were grouped into twenty-four species based on homologies of 16S rRNA gene sequences and biochemical properties. Isolated Bacillus cereus, Bacillus sphaericus, Morganella morganii, Serratia marcescens and a Klebsiella species killed 80% or more cutworms when injected at a dose of 5 × 10 5 cells per insect. In addition, cutworms killed by these isolates resembled observations made of caterpillars attacked by antlions. A culture-independent analysis showed that the isolated bacterial species are likely to be frequently present in the antlion crop. These results suggest that insecticidal microorganisms associate with antlions, and may promote the death of prey.

Optimal control of stochastic lattice of prey–predator models

We propose a stochastic lattice model to describe the dynamics of two animal species population, one being a prey and the other a predator. The system follows a stochastic dynamics composed of three Markovain processes: the first one describes the birth of prey; the second describes the death of prey and simultaneous birth of predator, the third describes spontaneous death of predator. The master equation is used to derive the time evolution of one and two site correlations. The stability of the stationary states of one-site correlations is studied. The optimal control functions that ensure the asymptotic stability of unstable stationary states are derived. In the case of one site approximation the densities of the vacant sites, prey sites and predator sites are obtained as functions of time for the controlled model.

Preliminary Observations on Chemical Preference, Antipredator Responses, and Prey-Handling Behavior of Juvenile Leioheterodon madagascariensis (Colubridae).

Innate responses to prey chemicals, antipredator responses, and prey-handling behavior of a Madagascan colubrid snake, Leioheterodon madagascariensis, were experimentally examined. In a chemical test, ingestively naive hatchlings flicked their tongues frequently to the chemicals prepared from the animal taxa included in their natural diets, suggesting the presence of innate chemical prey preference. In a second test, three different types of stimuli were presented to elicit antipredator responses of the hatchlings. In a nonmoving stimulus session, only a single snake struck and exhibited characteristic displays such as body flattening, neck flattening, head elevation, and jerk. In a moving stimulus session, either no specific responses or a simple flight response was exhibited. In a tactile stimulus session, the above characteristic displays were frequently exhibited. Among these, lateral neck tilting posture accompanying head elevation and neck flattening was unique to L. madagascariensis. In a third test, five types of prey animals were offered to juveniles to examine the effects of prey size and type on prey-handling behavior, but no such effects were detected. Direction of ingestion seemed to depend on initial bite position. Constricting behavior was observed only in a single trial. All but one prey were swallowed alive. This inflexibility of prey-handling methods in the juvenile snakes may reflect the characteristics of generalist feeders, which require ontogenetic experiences to handle prey efficiently. Although L. madagascariensis is considered to have well-developed Duvernoy's glands with enlarged, posterior maxillary teeth, the gland secretion did not seem to cause rapid death of prey.

Nonlethal Effects in the Ecology of Predator-Prey Interactions

.P ]redator-prey interactions have long captured the attention of ecologists, and with good reason. Predation leads inevitably to the removal of prey individuals from ecological systems, which can have major impacts on prey population dynamics and on entire ecosystems. Interest in predator-prey interactions can be traced to the foundations of modern ecology, from early work on predator-prey population dynamics by historical figures such as Lotka, Volterra, and Gause (Taylor 1984) to classic work on the role of predation in regulating species diversity (e.g., Paine 1966). Ecologists continue to be greatly interested in predation and its effects on populations, communities, and ecosystems (Crawley 1992, Carpenter and Kitchell 1993). A perusal of any recent textbook on ecology will not only confirm the importance of predation in modern ecology, but also illustrate the preeminence of the perspective on predation-that is, predation is seen as important only insofar as it results in the death of prey and their removal from the system. However, the obvious and sometimes dramatic lethal aspects of predation can obscure the nonlethal effects of the mere presence of predators in an ecological system. In the presence of predators, prey may alter their behavior so that they are more difficult

A Sacred Heart by Ron Watson, and: “Twin Peaks” Cherry Pie: New Poems by Robert Peters, and: Canyonvue by Scott Preston, and: 301 by Ford Swetnam

Reviews 413 boy and his grandfather finally seek their tarpons, here where the battle loses all significance in light of the ultimate death of both predator and prey. The Death of Tarpons is a story of innocence moving through a brutal world, a story told with a narrative voice so sincere in its attempt to make sense of a mean and random world that we can’t help but share in the journey toward a life of love, compassion, and wonder. JANE BRADLEY University of Toledo A Sacred Heart. By Ron Watson. (Pocatello, Idaho: The Redneck Press, American Poetry at the Millennium Series Number 5, 1994. 12 pages, $6.00.) “Twin Peaks” Cherry Pie: New Poems. By Robert Peters. (Pocatello, Idaho: The Redneck Press, American Poetry at the Millennium Series Number 6, 1995. 12 pages, $6.00.) Canyonvue. By Scott Preston. (Pocatello, Idaho: The Redneck Press, American Poetry at the Millennium Series Number 7, 1995. 12 pages, $6.00.) 301. By Ford Swetnam. (Pocatello, Idaho: The Redneck Press, American Poetry at the Millennium Series Number 8, 1995. 12 pages, $6.00.) Four recent chapbooks from the Redneck Press vary consider­ ably in quality, but all testify to the vitality of a uniquely western American poetry at the end of our century. Ron Watson’s A Sacred Heart, a tame book, is a cycle of love poems with all the cliched ups and downs typical of poems in an exaggerated courtly love tradition—or maybe in a subdued Harlequin romance tradition. Watson’s forte is the intensely person­ al image, never shying short of sentimentality: “i . . . search the wall for words/ to give this moment birth—/ i want a phrase immortal enough/ to swim in forever.” Once past this obligatory eternizing 414 Western American Literature conceit, though, we get to the real essence of the love poem: “i hear you drawing water for a bath,/ your voice soft with janis/ as she coos a slow one, smooth/ as southern comfort.” If Watson would drop the tired freshman tactic of using all lower case personal pronouns, though, he might strengthen an otherwise delicate poetic voice. America’s favorite curmudgeon of poetry, Robert Peters—chief blue ribbon judge of the Great Poetry Bake-Off series, whose famous prose style captures the essence of the best poetic styles of our time, in this new chapbook shows us his poetry is almost as good as his prose. This volume is a fast-paced verbal video of contempo­ rary western life—Nevada, Indian cemeteries, skateboarding, and second-hand celebrity. Some poems are loud, raunchy, and frenetic with activity—with the excitement of Nevada casinos: “Silver dol­ lars clang/ Cherries, plums, and lemons/ whip past: clunk, and stop./ $240 is my limit.” A quiet poem, but no less the verbal video version of a PTV (Poetry Television) video is “Indian Burial Ground” where “Hares bound and skitter/ through creosote brush and lupine./ Bleached name-hieroglyphics, an old woman’s/ plastic flowers. Rodent bones. Massed clouds./ Spinning hawks. Rocks and boul­ ders.” Three thumbs up for these poems, new poems that are raucus, primitive, and raw as the new West itself. Scott Preston, one of the foremost scholars of cowboy poetry, in Canyonvue delves into the “intensely personal realms of madness” as he confronts Idaho’s “evil mental health codes” in a volume devoted to poetic experiences at Canyon View Hospital. In his end­ note Preston claims that “Idaho’s reputation as the most Neanderthal state in the union gets one wacky boost” with these poems. Well, while competent poetry in a most deeply personal way, Canyonvue is hardly “wacky”— thank goodness. Instead, here are poems of bit­ terness and mental anguish, poems of rage against an insane system: “The State arrives/ with a lamp &/ a pleasant expression/ perfectly primed/ to bleach another month/ of my life away.” Preston is at his best, by far, in character portraits such as that of “the little chi­ huahua woman” who has “a voice that could drive a cartoon insane” or the Director of Nursing who “was bitter/ as chewed aspirin/ and almost as attractive.” Here is terrific black humor—but it is hardly “wacky.” Reviews 415 Ford Swetnam is a prominent...

Northern Pacific Rattlesnakes (Crotalus viridis oreganus) Meter Venom When Feeding on Prey of Different Sizes

taped as they each struck small and large laboratory mice (Mus musculus). Venom measurements were made by enzyme-linked immunosorbent assay (ELISA) of whole-animal homogenate. Although medium and large snakes expended similar quantities of venom, both groups injected significantly more venom into large mice than into small mice. Slow-motion videotape analyses indicated that behavioral aspects of striking were similar for medium and large snakes and did not differ between size classes of prey. Likewise, no behavioral aspect of striking was correlated with the quantity of venom expended. Thus, venom expenditure was not a consequence of or constrained by some extrinsic aspect of striking such as duration of fang contact. Instead, the rattlesnakes metered more venom into larger prey through intrinsic control of venom delivery. Because of the predatory advantages for quick death and efficient digestion of larger prey, injection of more venom into larger prey is likely an adaptive strategy.

Laboratory Rearing of Hydrometra australis (Hemiptera: Hydrometridae)

The surface-dwelling aquatic insect Hydrometra australis Say (Hemiptera: Hydrometridae) is difficult to rear. Although most field-collected nymphs reared on a diet of Drosophila in the laboratory develop to the adult stage, mate, and reproduce successfully (Lanciani 1975), only a small percentage of individuals reared from the egg stage on this food reach adulthood. In previous laboratory rearing attempts using different container sizes, different substrata, and Drosophila as food, the maximum survival I have observed in individuals reared from egg to adult is 40%. The closely related species Hydrometra martini Kirkaldy has been cultured on Drosophila (Sprague 1956), but its survival rate was not given. Collembolans have been cited as a common food source of hydrometrids, e.g., H. martini (Sprague 1956) and Hydrometra stagnorum (Linnaeus) (Arrow 1895). In northern Florida, H. australis can be often seen in the field feeding on aquatic collembolans, which are abundant in many shallow aquatic habitats frequented by H. australis. These observations suggested a rearing method for H. australis using aquatic collembolans as food. Six female H. australis were collected from Lake Alice, Gainesville, Florida, U.S.A. on 17-IX-1989, placed individually in plastic petri plates lined with moistened absorbent paper, and fed 3 frozen Drosophila melanogaster Meigen per day. Eggs removed from these plates to establish a laboratory parental generation were placed individually in plastic vials (3 cm in diameter and 7 cm in height) that were half to three-fourths full of water. The water surface was completely covered with plants of 2 species of duckweed, Lemna minor Linnaeus and Spirodela polyrhiza (Linnaeus). A circular hole cut in each vial cap was covered with a piece of screen. The vials were placed in a constant-temperature chamber held at 28?C with a 12-h light-dark cycle. Approximately 20 or more live collembolans (Sminthurides sp.) of various sizes collected from a local temporary pond were added to each vial when the Hydrometra eggs hatched. (Collembolans were easily field-collected by slowly skimming the duckweed-covered pond surface with the edge of a plastic box.) As the number of collembolans in the vials dwindled, more were added so that prey were always abundant. Uneaten collembolans survived well, so contamination by death of excess prey did not occur. As individuals of the parental generation of H. australis reached the adult stage, females and males were paired. The first 27 eggs laid, which were from two females, were then placed individually in plastic vials to establish the subject generation. This generation was reared as was the parental generation, except that the vials were removed briefly from the constant-temperature chamber 4 times each day (within the periods 7-9a.m., lla.m.-lp.m., 4-6p.m., and 8-lOp.m.) to be checked for molts. Twenty-six of the 27 subject-generation eggs successfully developed to the adult stage on an exclusive diet of collembolans. The mean stadium of each of the 5 immature instars is listed in Table 1. These stadia are consistently shorter than those (Lanciani 1975) determined on Drosophila-fed individuals (Table 1; P < 0.001 for each instar, t-test). The comparisons of instars 2 to 5 are not ideal because in the Drosophila-fed group, data for instars 2 to 5 were obtained from field-collected instars 1 to 4, respectively, that were maintained in the laboratory through the next instar only. The Collembola-fed