The majority of lady beetle species (Coleoptera: Coccinellidae) are well-known control agents for a variety of crop pests. They’re perhaps most commonly associated with aphids (Hemiptera: Aphididae), tiny sap-feeding insects that can cause significant damage to cultivated plants. Beneficial lady beetles will also feed on other soft-bodied prey including scale insects and the eggs and larvae of many different flies, moths, and butterflies.
Not all lady beetles are champions of human farming, however. Some species feed on plants and a few are capable of doing noticeable harm in gardens and farms. Although the damage they cause isn’t economically significant, this is one example of how there are often exceptions to the rules among insect groups.