Most widespread widow spider

The most widespread species in the widow spider genus Latrodectus, which includes such notoriously venomous species as the American black widow and Australia's redback, is the brown widow L. geometricus. Although it is believed to have originated in South Africa, it has been inadvertently distributed by humans in cargo, etc, throughout much of the world, and is now on record from the USA (including Hawaii), the Dominican Republic, El Salvador, Costa Rica, Brazil, Australia, Afghanistan, China, Japan, Pakistan, Thailand, the United Arab Emirates, Tanzania, South Africa, and Cyprus.

There is evidence to suggest that the brown widow, more aggressive but less venomous than the black widow, is supplanting the latter species in certain areas of southern California where it has recently become established. If so, this will mean that such areas will actually become safer to humans, an unexpected outcome of this invasive species' very considerable success at establishing itself in new geographical locations.