Badumna longinqua (L. Koch, 1867) (Desidae) is a native spider from Australia and was introduced into New Zealand, Japan, United States, and South America where it was recorded only from Uruguay (Platnick 2012). Recently, it was found in Germany (Kielhorn and Rödel 2011). The introduced spider B. longinqua is a medium-sized cribellate spider and commonly known as “grey house spider” (Simó et al. 2011). Badumna webs consist of a retreat with numerous sheets, radiating at various angles (Ubick 2005). This species can be easily found living in tree trunks, rock walls and also is very common in human habitats, such as window frames, wall crevices, inside or outside houses, and in urban parks (Simó et al. 2011). It has mainly spread through inert phoresy on vehicles and merchandise, where they build their webs (Main 2001). In 2013, B.longinqua the first specimens of this species were recorded from Port Elizabeth and Bloemfontein in South Africa.
Preliminary species distribution modeling suggest that coastal areas in and around Port Elizabeth is particularly suitable for this species. Probability of occurrence decreases inland but still remains relatively large (>0.3) along the coast towards Cape Town and along the Eastern coast.
Dictyna civica (Dictynidae) is native to Europe or North Africa and has been introduced to Turkey and North America as well. Dictyna civica has been spreading in Central Europe (Billaudelle 1957, Hertel 1968) occasionally colonizing the outside surface of buildings in high densities. This species live inside buildings and cause regular cleaning activities due to their web spinning activity (Nentwig and Kobelt 2010). In South Africa, D. civica has only been recorded in Roodeplaat near Pretoria in 2012. They construct flat webs against the surface of walls, fences, window frames, ceilings, roofs, in and out of the buildings. Their impacts are largely linked to being a nuisance on walls where they can cover extensive surface areas. Preliminary distribution modeling suggest that Pretoria is climatically unsuitable for this species with probabilities of occurrence increasing substantially for areas in the Nama Karoo.
None of these species are of any medical importance.
If anyone has seen these spiders, please contact:
Prof Stefan Foord
Department of Zoology, Centre for Invasion Biology
University of Venda