Expression of Brown and Southern Black Widow Spider (Araneae: Theridiidae) Latrotoxins Is Tissue- and Life Stage-Specific for α-Latroinsectotoxins and δ-Latroinsectotoxins and Is Ubiquitous for α-Latrotoxins.

Widow spiders are widely known for their potent venom toxins that make them among the few spiders of medical concern. The latrotoxins are the most well-studied widow toxins and include both the vertebrate-specific latrotoxins and the insect-specific latroinsectotoxins (LITs). Previous studies have shown that toxins are not limited to expression in the venom glands of adult spiders; however, gaps exist in latrotoxin screening across all life stages for brown widows, Latrodectus geometricus and southern black widows, Latrodectus mactans.