Brown Widow

Latrodectus geometricus females are 7–10 mm with a mottled tan-to-dark-brown abdomen bearing a geometric pattern of white, black and orange marks and boldly banded legs; the ventral hourglass is orange to yellow-orange rather than red. The unmistakable diagnostic is the egg sac: a spiky, tufted, 'sputnik' sphere holding 100–200 eggs, with a female producing far more sacs than a black widow over her 6–12 month life. Development from egg to adult takes about 60–90 days at 25–30°C, allowing very rapid population growth in warm climates.

Brown widows are less reclusive than black widows and build shallower, more exposed tangle webs, often at eye level around structures. Venom is comparably potent drop for drop but the spider injects far less and is markedly more timid, so bites are usually mild and local — pain and redness at the site rather than full latrodectism. They are highly fecund and displace native black widows in urban landscapes. Activity is chiefly nocturnal, with the female retreating to a silk pocket by day and the presence of multiple spiky egg sacs signalling an established, growing colony.