All species possess basic characteristics which distinguish them from other species. However, genetic research has demonstrated the uniqueness of individuals in sexually reproducing organisms. Also, population studies have indicated that species consist of local units that can vary in both space and time. The differences observed among and within populations may extend to any part of the genotype and are believed to result from genetic adjustments that lead to the production of a phenotype adapted to the local environment. The idea that environmental selection patterns are responsible for the regulation of genetic variation in populations suggests the need to conduct ecological genetic studies on native populations being sampled to establish laboratory colonies for biological and/or genetic control programs. In the absence of field information, sampling procedures tend to be haphazard in terms of securing adequate amounts and kinds of genetic variation for initial colonization purposes.