Brown widow spiders, scientifically known as *Latrodectus geometricus*, are swarming Israel. Recent research reveals that 86% of these spiders carry a strain of Rhabdochlamydia, a bacterium related to Chlamydia. However, it's important to note that bites from these spiders do not transmit Chlamydia.

In a study comparing microbial communities, Dr. Monica Mauri and her team at Ben-Gurion University of the Negev found that this bacterium is vertically transmitted to offspring, indicating its significant role in the biology of the brown widow spider. The research highlights the bacterium's potential contribution to the invasive success of this species, which thrives in human environments and competes with local spider species.

Prof. Michal Segoli, a past fellow of the IIAS and a member of the Mathematical Modelling of Biological Control Interaction to Support Agriculture and Conservation research group at IIAS, along with Prof. Yael Lubin, also contributed to this research. Their work emphasizes the importance of characterizing symbiotic bacteria to understand their ecological interactions and responses to environmental changes.

Their findings suggest that the high microbial diversity in brown widow spiders may support the hypothesis of their origin in South Africa and their subsequent global spread.