These spiders are found all over the desert. They like to make their nests in furniture, water heaters, closets, garages, air conditioners, and bushes, where they happily catch and snack on crickets. Black Widows are the most poisonous of all desert spiders and it’s a good idea to sign up for regular pest control service to keep these deadly pests at bay. Wondering if your visiting pest is a Black Widow? Look for eight legs, a black body color, and a red mark on the bottom of the spider.