Pre- and post-introduction patterns in neutral genetic diversity in the leafy spurge gall midge, Spurgia capitigena (Bremi) (Diptera: Cecidomyiidae)

A comparison of control results for the alien invasive woodwasp, Sirex noctilio, in the southern hemisphere

“…in Tasmania and New South Wales, releases of R. persuasoria and M. nortoni in parts of South America, and releases of I. leucospoides in South Africa, have been from very small numbers of wasps ( Table 1 ). Such small releases of biological control agents have been known to result in genetic bottlenecks ( Hufbauer et al , 2004;Lloyd et al , 2005 ). Although the exact influence of genetic bottlenecks on the success of biological control agents is unclear, low genetic diversity could decrease the ability of the biological control organism to adapt to new environments and host types ( Baker et al , 2003;Roderick and Navajas, 2003;Lloyd et al , 2005 ).…”

Comparative genetic studies of native and introduced Coccinellidae in North America

“…Hoy, 1985;Waage, 1990). The genetics of a released natural enemy, however, are rarely examined Lloyd et al, 2005) in relation to the breeding structure of that species that will create an effective population for successful colonization. An understanding of the breeding structure of an introduced natural enemy in their home territories may be a critical component determining the size of releases that are necessary for successful establishment.…”

“…The ecology and genetics of invading organisms have received considerable research attention, yet with notable exceptions (Baker et al, 2003;Hufbauer et al, 2004;Lloyd et al, 2005) little has been accomplished to link improved knowledge of genetics with guidance for the practice of biological control (Roderick, 1992). Questions persist regarding the importance and relationship of genetic variation to the practice of biological control (Unruh & Messing, 1993;Unruh & Woolley, 1999;Roderick & Navajas, 2003).…”

“…Indeed, representative genetic variation has been considered a sine qua non for successful colonization and establishment of natural enemies (Force, 1967;Roush, 1990;Hopper et al, 1993;Baker et al, 2003;Hufbauer et al, 2004;Wajnberg, 2004;Lloyd et al, 2005). Historically, discussions in the literature focused on the merits of collecting natural enemies from marginal vs central populations to maximize variability (Remington, 1968;Myers & Sabath, 1981).…”

“…Additionally, for most species of introduced natural enemies, data to support the relationship between genetic variation and levels of biological control is lacking (Unruh & Woolley, 1999). Recently, however, evidence of mild genetic bottlenecks was documented in populations of the parasitoid wasp Aphidius ervi Haliday (Hymenoptera: Braconidae) and the leafy spurge gall midge Spurgia capitigena (Bremi) (Diptera: Cecidomyiidae), two species that were successfully introduced into North America for biological control Lloyd et al, 2005) A number of releases of exotic ladybird beetle species for biological control have been made in North America, but the results of these efforts have been poor, with an estimated rate of establishment of ~ 9% (Gordon, 1985). Do readily observed genetic phenomena underlie this low rate of establishment?…”