Some Delay Models for Juvenile vs. Adult Competition

Abstract

Models of competition have played a central role in theoretical population dynamics and ecology. The vast majority of mathematical models of competitve interactions that have been formulated have been done so with regard to highly aggregate state variables at the total population level and have ignored differences between individual organisms, in effect treating all individuals of a species as identical. Biological populations generally consist, however, of individuals with diverse physiological characteristics, such as age, body size or weight, life cycle stages, etc., (with intra-species variances that in fact can exceed inter-specific variances amongst competing species) and it has become widely recognized that this diversity can have a significant influence upon population level dynamics (Werner and Gilliam (1984), Ebenman and Persson (1988), Metz and Diekmann (1986)). Models that ignore individual level physiological variances cannot, except in the simplest of cases, adequately account for the mechanisms that result in competition between individual organisms for limited resources. In particular, intra-specific competition can be accounted for in such models only in highly qualitative ways at best.