A size-structured population dynamics model of Daphnia

A size-structured population dynamics model of Daphnia

Size-structured risk assessments govern Daphnia migration

One of the more fascinating phenomena in nature is animal mass migrations and in oceans and freshwaters, diel variations in depth distribution of zooplankton are a phenomenon that has intrigued scientists for more than a century. In our study, we show that zooplankton are able to assess the threat level of ultraviolet radiation and adjust their depth distribution to this level at a very fine tu...

Local Stability of a Quasi-linear Age-size Structured Population Dynamics Model

The local stability of a quasi-linear age-size structured population model studied in Tchuenche (2007) is analysed. If a certain threshold parameter known as the basic reproductive rate is less than unity, then the trivial steady state is locally asymptotically stable. Also, it is shown that if the only real root of the equation R(m′) = 1 is negative, then, the non trivial steady state is local...

On periodic cohort solutions of a size-structured population model

We consider a size-structured population model with discontinuous reproduction and feedback through the environmental variable \substrate". The model admits solutions with nitely many cohorts and in that case the problem is described by a system of ODEs involving a bifurcation parameter. Existence of nontrivial periodic n-cohort solutions is investigated. Moreover, we discuss the question wheth...

Effects of growth curve plasticity on size-structured population dynamics.

The physiological-structured population models assume that a fixed fraction of energy intake is utilized for individual growth and maintenance while the remaining for adult fertility. The assumption results in two concerns: energy loss for juveniles and a reproduction dilemma for adults. The dilemma results from the possibility that adults have to breed even if metabolic costs fail to be covere...