Yes, they are all in the Latrodectus family, all have venom containing the neurotoxin latrotoxin, which causes latrodectism (pain, vomiting, muscle rigidity, sweating).
Australian Redbacks are Latrodectus hasseltii:
New Zealand Katipo are Latrodectus katipo:
Western Black Widows are Latrodectus hesperus:
Southern Black Widows are Latrodectus mactans:
Female:
Male:
Northern Black Widows are Latrodectus variolus:
European Black Widows are Latrodectus tredecimguttatus:
South American Black Widows are Latrodectus corallinus:
Yes, they are all in the Latrodectus family, all have venom containing the neurotoxin latrotoxin, which causes latrodectism (pain, vomiting, muscle rigidity, sweating).
Australian Redbacks are Latrodectus hasseltii:
New Zealand Katipo are Latrodectus katipo:
Western Black Widows are Latrodectus hesperus:
Southern Black Widows are Latrodectus mactans:
Female:
Male:
Northern Black Widows are Latrodectus variolus:
European Black Widows are Latrodectus tredecimguttatus:
South American Black Widows are Latrodectus corallinus:
https://en.wikipedia.org/wiki/Latrodectus
Thank you for the well sourced response.
I used to be in a black widow-free area but it seems that European “13 spots” one is now starting to show up here.
Probably not good news.