Database Reference
In-Depth Information
Chapter 3
Insect Dynamics
In this chapter we develop three different models of insect dynamics. From the
perspective of “dynamic modeling of pestilence,” insects surely need special
attention—they are the carriers of many of the viruses that affect the health of
humans and other animals, and they cause billions of dollars of damage to food
supplies around the world every year. We try to control their population levels,
having long ago realized they multiply and evolve too fast for elimination.
Insects are among the major vectors of disease. They provide an excellent way
to understand the dynamic modeling of a complicated disease vector composed of
different age classes.
From a modeling perspective, insect dynamics can be used to effectively illus-
trate a set of techniques and skills that will prove important for gaining a deeper
understanding of
(a) the challenges of matching laboratory and field experiments to models,
(b) the underlying mechanisms by which living systems evolved and adjust to their
external environment,
(c) the distinct roles that different life stages or age cohorts may play in the trans-
mission of, or infection with a disease.
The following three sections of this chapter respectively address these issues. Later
chapters either explicitly or implicitly make use of the insights gained here.
3.1 Matching Experiments and Models of Insect Life Cycles
To better understand the dynamics of insect populations, we model the life cycle of
an insect, simplified into two stages, egg and adult. Typically, the data used in un-
derstanding insect population dynamics come from laboratory experiments in which
one watches each egg and notes when it dies or hatches. Data from such an exper-
iment (at constant temperature) might look like that shown in Table 3.1 of the life
history of 100 new insect eggs. Note how the final number of survivors must equal
the total number hatched.
