Exotic ants in The Netherlands (Hymenoptera: Formicidae)

In the period 1926 to 1944, Starcke reported regularly on the occurrence of exotic ants in The Netherlands (Starcke 1926a, 1926b, 1933, 1943, 1944). A motivation was given in his report: “It seemed me good to draw up the account of this period, before a new period of increasing central heating and plane traffic creates new possibilities” (Starcke 1943). Since then, publications on exotic ant occurrences were published only incidentally. Exotic ant species are currently given considerable worldwide attention, reflecting the increasing economic and agricultural impact, health effects on humans, displacement of native species, and disruption of natural ecosystems (Ward et al. 2006). Knowledge of exotic ants is nevertheless limited. Therefore, acquiring data on them is important in order to understand why some species become successful biological invaders. McGlynn (2002) published a list of 137 ants that have been transported to new regions around the world. Nineteen of them were recorded from Europe, especially from the Iberian Peninsula. For most European countries there are no published records, or only incomplete lists or outdated records. For example, from Slovenia one species is recorded to have established (Bracko 2000), from Belgium three (Dekoninck et al. 2006a, b), from Austria eight (Steiner et al. 2002), and from Switzerland nine species (Wittenberg 2005, UGZ 2006), while the early list of exotic taxa of Great Britain counted 56 species (Donisthorpe 1927). In most of these cases the observations are only incidental and information on establishments is scarce. The list for The Netherlands in this paper counts 76 exotic species. The term ‘exotic’ is used to indicate non-native or alien origin (McGlynn 2000, Anonymous 2006a). All species considered in the following lists are exotic and predominately from (sub-)tropical origin. All were accidentally introduced by human activity.