Ladybugs (family Coccinellidae) are widely celebrated as beneficial insects in gardens and agriculture due to their appetite for aphids. This reputation often overshadows the fact that their diet is far more complex and varied. The roughly 6,000 species of ladybugs worldwide exhibit a vast range of feeding behaviors, consuming different types of prey, plant matter, and fungi. Understanding their dietary needs reveals that these beetles are highly adaptable omnivores and specialists, seeking diverse nourishment when preferred prey is unavailable.
The Predatory Menu Beyond Aphids
While aphids are a favored food source, the majority of ladybug species are generalist predators that consume a wide array of other small, soft-bodied insect pests. This protein-rich diet is particularly important for larvae to fuel their rapid growth and development. Susceptible prey includes plant-sucking pests such as scale insects, mealybugs, and whiteflies, which damage crops and ornamental plants.
Ladybugs are effective hunters because their prey is typically slow-moving or stationary and lacks strong defensive mechanisms. They also target minute spider mites, often found on the undersides of leaves where they spin fine webbing. Furthermore, many predatory ladybugs consume the eggs of moths, beetles, and other arthropods, eliminating pests before they hatch into destructive larvae.
Survival Foods Nectar, Pollen, and Fungi
Many predatory ladybug species are not strictly carnivorous and supplement their diet with non-prey food sources when insect populations decline. Nectar, the sugary liquid produced by flowers, provides a readily available source of carbohydrates for energy. This is useful for adult beetles searching for mates or preparing for dormancy, such as overwintering.
Pollen, collected from flowering plants alongside nectar, offers a protein boost when insect prey is scarce. This supplemental protein supports the ladybug’s reproductive health and overall maintenance. Another common energy source is honeydew, the sticky, sugar-rich excretion left behind by aphids and certain scale insects. Ladybugs may also consume fungal spores or mildews, which provide moisture and additional nutrients during lean times.
The Ladybug Vegetarians and Fungivores
Not all members of the Coccinellidae family are beneficial predators; a minority of species have evolved to be primarily herbivorous or fungivorous. These species feed exclusively on plant material or fungi, representing a departure from the predatory norm. The Mexican Bean Beetle (Epilachna varivestis) is a well-known example of a herbivorous ladybug considered a pest of agricultural crops.
Both the adults and larvae of the Mexican Bean Beetle feed mainly on the leaves of legumes, such as beans and soybeans. They scrape away the soft tissue, leaving behind the leaf veins and upper epidermis, which creates a distinctive, lace-like skeletonization. Other specialists, like those in the genus Psyllobora, feed on powdery mildews, consuming the fungal threads and spores for their entire life cycle.