A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus Latrodectus (widow spiders) as well as at least one species of another genus in the same family, Steatoda nobilis.[1] Latrotoxins are the main active components of the venom and are responsible for the symptoms of latrodectism.
The following latrotoxins have been described: five insecticidal toxins, termed α, β, γ, δ and ε-latroinsectotoxins, one vertebrate-specific neurotoxin, alpha-latrotoxin, and one toxin affecting crustaceans, α-latrocrustatoxin.[2]