There aren’t actually that many scorpions in the desert. The lack of water and crickets limits their population to of very low number. That's why when you walk into the desert you don't really see scorpions. However, when we build houses in the desert, we bring something with us: water. This water allows the crickets and the roaches to breed exponentially and draws from the greenbelt the scorpions to the property.
You can see here a grass that's not indigenous to Arizona able to grow because the excess water if a move around this location, you'll be able to see the actual dripper here in my hand that releases water and keep this plant alive. This additional water causes the scorpion population to boom right around homes. As they expand their territories the eventually move inside the home.
Eventually they notice that there are cricket infestations inside the walls of the home. This material here is cricket droppings, or cricket fecal matter. This is actually normal here in the desert. The crickets love the cooler air that comes out from the wall. They actually can fit up into that gap right here this infestation of crickets draws the scorpions further into the home and they start showing up in your wife’s shoes.