This trap uses a food-based lure and color proven attractive to fruit flies. Simply add the liquid attractant to the trap and it starts catching fruit flies within minutes. Each trap comes with a 30-day supply of attractant and is reusable with RESCUE! Fruit Fly Trap Attractant Refills. With more holes and a higher concentration of attractant, our exclusive design is proven to catch adult fruit flies eight times better than competitive traps. Our trap catches fruit flies that congregate and breed near fruit, vegetables and food scraps.