Black widow spiders are the largest of the cobweb weaver spiders. They are very common in nature and like dark, small spaces and are often found between rocks, log piles, in dark sheltered spots like the corners of your mailbox or in your propane meter tank.
Black widows typically eat other insects, their favorite being mud-dauber wasps. But they also have enemies. Some parasitic wasps will sting and paralyze the black widow. It is also a favorite of the Praying Mantis.
Fortunately my husband saw this spider before he picked up the rock and was good enough to call me to grab my camera. He knows me too well.
Linking up for Macro Monday.