An Alternative Formulation for a Distributed Delayed Logistic Equation

Bull Math Biol. 2018 Jul;80(7):1713-1735. doi: 10.1007/s11538-018-0432-4. Epub 2018 Apr 19.

Abstract

We study an alternative single species logistic distributed delay differential equation (DDE) with decay-consistent delay in growth. Population oscillation is rarely observed in nature, in contrast to the outcomes of the classical logistic DDE. In the alternative discrete delay model proposed by Arino et al. (J Theor Biol 241(1):109-119, 2006), oscillatory behavior is excluded. This study adapts their idea of the decay-consistent delay and generalizes their model. We establish a threshold for survival and extinction: In the former case, it is confirmed using Lyapunov functionals that the population approaches the delay modified carrying capacity; in the later case the extinction is proved by the fluctuation lemma. We further use adaptive dynamics to conclude that the evolutionary trend is to make the mean delay in growth as short as possible. This confirms Hutchinson's conjecture (Hutchinson in Ann N Y Acad Sci 50(4):221-246, 1948) and fits biological evidence.

Keywords: Adaptive dynamics; Decay-consistent delay; Dirac delta, gamma, uniform, and tent distributions; Hutchinson’s conjecture; Integro-differential equations; Lyapunov functionals; Single species delayed growth models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Conservation of Natural Resources / statistics & numerical data
  • Ecosystem
  • Humans
  • Introduced Species / statistics & numerical data
  • Logistic Models*
  • Mathematical Concepts
  • Models, Biological*
  • Mutation
  • Population Dynamics / statistics & numerical data*
  • Population Growth
  • Species Specificity