Ants are the bane of lady beetles. When a lady beetle approaches, the ant bites the beetle until it retreats in search of less obnoxious prey. Diet Lady beetles feed on a number of soft-bodied insects, including scales, mealybugs and spider mites, as well as insect eggs and small larvae, but most species love aphids. Depending on the species, a larva consumes 200 to 500 aphids during its development to pupal stage, and an adult consumes 300 to 400 per month. An adult will consume as much as 5,000 aphids in its lifetime.
Some species also eat pollen and fungal spores.
Unfortunately, when the lady beetles clean out their food supply, they disperse to find more food. When aphid populations return, lady beetle development may be too slow to keep up. In a typical garden that relies upon natural predators, the pest population will ebb and flow as the predator population moves in and develops then disperses. Patience and some tolerance are necessary on the part of the gardener to let the natural processes work. Control Generally not necessary.