Rapid Range Expansion of the Invasive Wasp<i>Polistes dominula</i>(Hymenoptera: Vespidae: Polistinae) and First Record of Parasitoids on this Species and the Native<i>Polistes marginalis</i>in the Western Cape Province of South Africa

Abstract

Invasive organisms are one of the greatest threats to global biodiversity (Pimentel et al. 2000; Rands et al. 2010). Considerable efforts have been made towards understanding of the processes driving invasion success which is essential when devising management strategies to limit the spread and impacts of invasive alien species (IAS) (Kolar & Lodge 2001). The success of IAS (animal species in particular) in novel regions is often attributed to the absence of natural enemies and a subsequent decrease in population regulation (Liebert et al. 2006), a phenomenon referred to as the enemy release hypothesis (Jeffries & Lawton 1984). As a result, biological control initiatives are largely geared to reconnect IAS with their natural predators and parasites (Irvin & Hoddle 2010). Unfortunately this necessitates the release of yet another alien organism (Veldtman et al. 2011).