Population genetics and molecular evolution of carrion-associated arthropods

A population is defined as a group of organisms of the same species that inhabit a particular geographic area, but which are also capable of interbreeding with inhabitants of other geographic areas (Hartl and Clark 1997). Therefore, this discussion should begin with the overall goal of defining a population of carrion-frequenting insects. There are two classic models which would be appropriate to define populations of carrion insects: the island model (Wright 1951) and the stepping stone model (Kimura and Weiss 1964). The island model assumes equal migration in and out of defined populations (=islands), whereas the stepping stone model assumes a greater degree of exchange between neighboring populations in which isolation by distance is observed. The actual population structure is likely a mixture of these two models for carrion insects and is not well known or defined. This chapter will focus on describing the population structure of carrion insects using existing molecular genetic techniques.