Human Impact Enables an Ecological Niche Shift for Invasive Widow Spiders

Abstract

Background: Predicting invasiveness requires understanding the propensity of a given species to thrive in areas with novel ecological challenges. The Australian redback spider, Latrodectus hasselti, a widow spider native to Australia and established in Japan, New Zealand, and Southeast Asia. We hypothesized that human impact is important for successful establishment of this anthropophilic species, and that climate factors may determine suitable habitat and thus predict invasive ranges.Results: We used ecological niche models to predict the potential distributions of this invasive species and to infer variables most important for population persistence by relating species observations to climatic variables and measures of human impact. We found L. hasselti distributions are positively influenced by human impact, particularly in the native range. Native distributions were most strongly predicted by maximum temperature and invasive distributions by precipitation seasonality.Conclusions: A strong climatic niche shift was detected in invasive populations compared to the natives. We infer that a preference for human-disturbed environments may underlie invasion and establishment in this species.