Black widows’ red hourglass tells birds ... detect reds three times better than bugs can. So he thinks widows evolved a discrete marking instead of becoming red all over, because birds could ...

Black widows are notorious spiders identified by the colored, hourglass-shaped mark on their abdomens. Several species answer to the name, and they are found in temperate regions around the world.

Black widow spiders, known scientifically as Latrodectus, are instantly recognizable by their glossy black bodies and the iconic red hourglass marking on their abdomens (at least the females are). And ...

The abdomen is spherical. The adult males are similar but with white markings, a slimmer abdomen, and longer legs. Juvenile ...

A relative of the black widow, the brown widow has lighter-colored markings, pale legs with dark joints, and a yellow-orange hourglass marking on its abdomen. The bite is neuropathic like the ...