Studying Population Dynamics Structure of Greenbottle Blowfly Using Generalized Additive Model

In the past, ecologists have been debating about the relative importance of density-dependent versus density-independent factors in determining population dynamics. Between 1989 and 1992, an experiment was conducted at the University of Reading for studying how both densityindependent and density-dependent factors affect greenbottle blowfly population dynamic structure. See Daniels (1994). Taking the duration of different life stages in the blowfly’s life cycle into account, Daniels decided to record the bi-daily abundance of larvas (L), “new” and “viable” pupae (P ), and adults (A) of 12 confined populations. She also designed a repeat 2 × 2 factorial experiment to study two levels of a density-independent factor—cadmium diet (treatment: present, or control: absent), and two levels of a density-dependent factor—initial density (high: 150 pupae and 150 adults, or low: 30 pupae and 30 adults). Three of the 12 populations are assigned to each of the four experimental conditions. There are approximately two years of data for each population. Based on common stochastic state-transition model for population dynamic, a partially specified biological model for the blowfly is: