Future climate may limit the spread of the Australian house spider Badumna longinqua (Araneae: Desidae) in South Africa

Abstract

Badumna longinqua (L. Koch, 1867) (Araneae: Desidae) is a web-building spider indigenous to eastern and southern Australia; it has been introduced to several countries in North and South America, as well as New Zealand, Japan and Germany. In South Africa, where it was formally recorded for the first time a decade ago, B. longinqua has been sampled from the southern coastal areas (Eastern and Western Cape provinces) and central Free State Province, with almost all of the records associated with synanthropic urban habitats. We present a brief account of its invasion history in the country. Predictive ecological niche models suggest that only the southern coastal areas represent suitable habitat. This suggests that samples from the Free State (only in horticultural nurseries) can be attributed to regular translocations from the southern coastal areas, but that an unsuitable climate there prevents long-term establishment. Future climate change may further restrict this species, which prefers year-round warm, humid areas with low seasonal variability, climatic conditions that are predicted to become increasingly rare in South Africa.