Geometric factors influencing the diet of vertebrate predators in marine and terrestrial environments

Predator–prey relationships are vital to ecosystem function and there is a need for greater predictive understanding of these interactions. We develop a geometric foraging model predicting minimum prey size scaling in marine and terrestrial vertebrate predators taking into account habitat dimensionality and biological traits. Our model predicts positive predator–prey size relationships on land but negative relationships in the sea. To test the model, we compiled data on diets of 794 predators (mammals, snakes, sharks and rays). Consistent with predictions, both terrestrial endotherm and ectotherm predators have significantly positive predator–prey size relationships. Marine predators, however, exhibit greater variation. Some of the largest predators specialise on small invertebrates while others are large vertebrate specialists. Prey–predator mass ratios were generally higher for ectothermic than endothermic predators, although dietary patterns were similar. Model-based simulations of predator–prey relationships were consistent with observed relationships, suggestin

Chemotactic predator-prey dynamics

A discrete chemotactic predator-prey model is proposed in which the prey secrets a diffusing chemical which is sensed by the predator and vice versa. Two dynamical states corresponding to catching and escaping are identified and it is shown that steady hunting is unstable. For the escape process, the predator-prey distance is diffusive for short times but exhibits a transient subdiffusive behavior which scales as a power law $t^{1/3}$ with time $t$ and ultimately crosses over to diffusion again. This allows to classify the motility and dynamics of various predatory bacteria and phagocytes. In particular, there is a distinct region in the parameter space where they prove to be infallible predators.Comment: 4 pages, 4 figure

Fluctuations and Correlations in Lattice Models for Predator-Prey Interaction

Including spatial structure and stochastic noise invalidates the classical Lotka-Volterra picture of stable regular population cycles emerging in models for predator-prey interactions. Growth-limiting terms for the prey induce a continuous extinction threshold for the predator population whose critical properties are in the directed percolation universality class. Here, we discuss the robustness of this scenario by considering an ecologically inspired stochastic lattice predator-prey model variant where the predation process includes next-nearest-neighbor interactions. We find that the corresponding stochastic model reproduces the above scenario in dimensions 1< d \leq 4, in contrast with mean-field theory which predicts a first-order phase transition. However, the mean-field features are recovered upon allowing for nearest-neighbor particle exchange processes, provided these are sufficiently fast.Comment: 5 pages, 4 figures, 2-column revtex4 format. Emphasis on the lattice predator-prey model with next-nearest-neighbor interaction (Rapid Communication in PRE

Effects of demographic stochasticity on biological community assembly on evolutionary time scales

We study the effects of demographic stochasticity on the long-term dynamics of biological coevolution models of community assembly. The noise is induced in order to check the validity of deterministic population dynamics. While mutualistic communities show little dependence on the stochastic population fluctuations, predator-prey models show strong dependence on the stochasticity, indicating the relevance of the finiteness of the populations. For a predator-prey model, the noise causes drastic decreases in diversity and total population size. The communities that emerge under influence of the noise consist of species strongly coupled with each other and have stronger linear stability around the fixed-point populations than the corresponding noiseless model. The dynamics on evolutionary time scales for the predator-prey model are also altered by the noise. Approximate $1/f$ fluctuations are observed with noise, while $1/f^{2}$ fluctuations are found for the model without demographic noise

A Microfoundation of Predator-Prey Dynamics

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 organisms‘ risk of being preyed upon during predation. Like consumers, organisms face a ‘budget constraint‘ 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 dynamics derived here turn out to differ significantly from those assumed in the standard Lotka-Volterra model.organism, biomass, species, population, predator-prey dynamics

IMPLEMENTASI MODEL PREDATOR-PREY PADA JUMLAH LAPANGAN KERJA DAN JUMLAH PENCARI KERJA DI KOTA BANDUNG

Skripsi ini berisi tentang Implementasi model predator-prey pada jumlah lapangan kerja dan pencari kerja di kota bandung. Sistem predator-prey digunakan untuk memodelkan lapangan kerja dan pencari kerja. Data diambil dari Dinas Tenaga Kerja (DISNAKER) Kota Bandung. Data yang diambil selama tiga tahun (2010-2012) dan dikelompokan dalam kuartal (3 bulan). Dalam model ini, pencari kerja berperan sebagai mangsa dan lapangan kerja sebagai pemburu. Tingkat pertumbuhan alami dari lapangan kerja dan pencari kerja digunakan sebagai parameter predator-prey. Metode finite difference digunakan untuk menyelesaikan perhitungan sistem predator-prey. Solusi dari persamaan terdiri dari kondisi setimbang, laju pertumbuhan, vektor, dan perbandingan antara lapangan kerja dan pencari kerja berdasarkan waktu. Didapat bahwa model interaksi lapangan kerja dan pencari kerja mirip dengan model interaksi antar makhluk hidup dalam sistem biologi. Didapat pula, solusi equilibrium dari jumlah pencari kerja adalah 2313 dan jumlah dari lapangan pekerjaan 1229. Kata Kunci: Predator-prey, lapangan kerja, pencari kerja  IMPLEMENTATION PREDATOR-PREY MODEL ON AMOUNT OF JOBS AND EMPLOYEES IN BANDUNG This paper presents the modeling of job-employee dynamics in Bandung using predator-prey system. Based on its dynamics similarity, the predator-prey system is used to model the job-unemployment dynamics. The data of job and employee are obtained from the Department of Labor (DISNAKER) Bandung region. The data is taken for three years (2010-2012) and grouped in quartile (3 months). In this model, the employee is considered to be prey and job is considered to be predator. The natural growth of job and employee are used as predator-prey parameters while the interaction parameters are studied numerically. The forward finite difference is used to solve the predator-prey system numerically. The results consist of equilibrium condition, phase trajectory, vector field and the comparison of the number of job and employee with respect to time. It was found that to the selected interaction parameters, the job-employee dynamics mimics the predator-prey system. It was found too that the equilibrium solution for this case 2313 for employee and 1229 for job. Keyword: Predator-prey, jobs, employe