Pink spotted lady beetles benefit gardens
Throughout the summer gardening season, you will see many different insects in your garden.
Your first thought may be that most of these insects will cause damage to your plants, but keep in mind that not all insects are harmful. Some insects are beneficial to your garden and are a source of biological pest management.
One of these beneficial insects is the pink spotted lady beetle (Coleomegilla maculata). Like other ladybugs, the pink spotted lady beetle is a member of the beetle family Coccinellidae, its name originating from the Latin word coccineus, meaning “colored or dyed scarlet.”
The pink spotted lady beetle is native to North America and can be found throughout New England and into the south and midwest. They may be found on a wide variety of plants, but most often on field crops such as corn, wheat and potatoes as well as on low-growing plants including flowering ornamentals, vegetables and other plants attacked by aphids, mites and other soft bodied insects.
The life cycle of the pink spotted lady beetle begins with adults overwintering in large groups or aggregations. The adults overwinter in leaf litter, at the base of trees, under rocks or in protected areas of crop borders.
In the spring, the adults emerge in search of prey and to lay their eggs.
The eggs are very small, oval shaped and yellow. They can be found individually or in clusters on the underside of plant leaves. Larvae emerge within two to 10 days. Similar to other ladybugs, the pink spotted lady beetle larvae are “alligator shaped” with pointy projections on their backs. Their coloring varies with species, with the pink spotted lady beetle larvae colored black with orange spots and bands.
It is at this stage that the pink spotted lady beetle is often misidentified as a harmful garden pest due to the larvae looking so different from the adults. The larvae mature over the next several weeks and then attach themselves to a leaf to pupate.
Depending on the temperature, the pupal stage will last between three and 12 days before the adult pink spotted lady beetle emerges. Adults are oval and pink and have six black spots on each forewing and two additional black spots on the area behind their head. They are active from April through September and produce two to five generations each season.
Throughout their life cycle, pink spotted lady beetles are a beneficial insect for pest management in the garden. They prey on soft-bodied insects, primarily aphids, but also spider mites, thrips and scale insects. One larva will eat about 400 aphids before reaching the pupal stage and as an adult will devour about 300 aphids before laying eggs. It is possible for one beetle, through the course of its life, to consume as many as 5,000 aphids. Pollen also is an important part of the pink spotted lady beetle diet. Unlike most other ladybugs, pollen makes up to 50% of their diet.
One way to attract the pink spotted lady beetle to your garden is to plant flowers that produce an abundance of pollen. Early blooming plants, like dandelions (Taraxacum officinale), columbines (Aquilegia canadensis) and creeping phlox (Phlox stolonifera) are especially attractive to the pink spotted lady beetle as they provide a food source in early spring before aphids begin to populate. An added advantage to planting heavy pollen producing plants, such as sunflowers (Helianthus annuus), zinnias (Zinnia elegans) and asters (Eurybia spp. and Symphyotrichum sp.) is that they contribute to sustaining your garden as a pollinator friendly space.
If you have questions about pink spotted lady beetles or other beneficial insects, call the Butler County Master Gardener Garden Hotline at 724-287-4761, ext. 7, or email the Master Gardeners at butlermg@psu.edu.
Amy Cirelli is a Penn State Extension Butler County Master Gardener.
