title: Effects of random migration in population dynamics.
abstract: We study the influence of random migration of a species (may be insects) in the population dynamics when initially all the individuals live in a primordial site (their habitats may be trees). We assume (i) a finite number of sites, (ii) that migration occurs randomly to nearest neighbors, and (iii) an on-site age-structured population whose size varies according to Ricker's map. We find that even for a very small migration rate, the population density becomes appreciably affected. If migration is not allowed, depending on the value of the characteristic parameters, the population may display a chaotic oscillation; however, with migration permitted, the chaos is reduced or even suppressed, and the population density will oscillate with period 2 or period 4. We examined the effects of migration through higher-order iterations of the map, entropy, and time correlation function. We also considered a long chain, analyzing (a) the spatial correlation between sites, noting the occurrence of a transition in the correlation function between sites separated by odd and even units of distance and (b) the fluctuations in time of the populations when initially all sites are populated.
authors.affiliation: Departamento de Física, CCET, Universidade Federal de São Carlos, Rodovia Washington Luiz km 235, São Carlos, 13565-905, SP, Brazil. colato@ifsc.sc.usp.br
authors.forename: A
authors.initials: A
authors.lastname: Colato
authors.forename: S S
authors.initials: SS
authors.lastname: Mizrahi
mesh_terms: D000818:Animals; D004463:Ecology; D004641:Emigration and Immigration; D019277:Entropy; D006801:Humans; D007313:Insecta; D008954:Models, Biological; D015233:Models, Statistical; D008962:Models, Theoretical; D009991:Oscillometry; D011156:Population Density; D011157:Population Dynamics; D011158:Population Growth