Not a 'Crab'

When I was a kid in Miami, these little spiders were everywhere! We called them 'crab' spiders, But they aren't closely related to the true Crab Spiders.  They're called Spiny-backed orb-weavers aka spiny orb-weavers or spiny spiders, and are in the genus Gasteracantha. This one, since she is brightly colored and sporting those six prominent spines, is most likely a female. She's several times larger than the male who lacks those impressive spines and bright colors. Although they can bite, they're generally harmless to humans. Be on the lookout for them in your yard/garden.