Identifying the Donor Region within the Home Range of an Invasive Species: Implications for Classical Biological Control of Arthropod Pests

Foreign exploration is a major component of a classical biological control program. Exploration within the home range of the target can be a daunting proposition as the target is most likely rare with an irregular distribution. As costs and greater regulatory oversight increase, classical biological control programs targeting arthropods need to complete preliminary steps prior to embarking on a collecting trip that will return live natural enemies to quarantine for rearing and evaluation. These preliminary steps should be designed to maximize the likelihood of identifying the donor region within the pest’s home range from which the invading population originated. Two techniques can be used to help identify the target’s donor region(s): climate matching and haplotype identification. These techniques increase the likelihood of collecting natural enemies well suited to the climate of the receiving area and will result in natural enemies best adapted to the genetic structure of the invasive target population. Further, haplotyping studies may help clarify taxonomic uncertainty regarding the “true” identity of the target pest and may also help uncover conduits by which these unwanted organisms are moving from area to area. This paper details work completed on determining the home range of the avocado thrips, Scirtothrips perseae, and delineating the donor region within the prescribed home range. The implications of this approach for increasing the success rates of classical biological control of arthropods are discussed.