Lady beetles
Order: Coleoptera
Family: Coccinellidae
Description
Adults and larvae of lady beetles primarily feed on aphids and can also attack leafhoppers, mites, scale insects, thrips, whiteflies, and small caterpillars. One group of black lady beetles, commonly called spider mite destroyers (Stethorus spp.), are commercially available predators of spider mites. All coccinellids can be voracious predators. For example, larvae of the convergent lady beetle (Hippodamia convergens) may eat their weight in aphids, and adults can consume up to 50 aphids a day. The sevenspotted lady beetle (Coccinella septempunctata) can consume hundreds of aphids per day as an adult.
Lady beetle adults have round to oval shaped bodies. The most well-known lady beetles have black markings (spots) on bright red, orange, or yellow forewings which cover the abdomen. They typically measure about 6.5 mm (1/4 inch) long and their head is usually black with white markings. The larvae measure between 6.5-9.5 mm (1/4-3/8 inch) and are elongated, spiky, and have black bodies with orange or yellow markings.
Quick Facts
- Adults and larvae of lady beetles are predators that attack many pests such as aphids, mites, thrips, and other soft bodied insects.
- Naturally occurring populations of lady beetles are usually abundant where aphid populations are also abundant.
- Lady beetles are commercially available as biocontrol agents for aphid management. Any crop that is attacked by aphids will benefit from the presence of lady beetles. However, lady beetles are thought to be less effective biological control agents when aphids are at lower densities since they are highly mobile and will disperse to new locations when adequate prey is not available.
Lady beetle resting on a leaf. Image credits: Frank Peairs, Colorado State University, Bugwood.org
Convergent lady beetle and multicolored Asian lady beetle resting on hemp. Image credits: Whitney Cranshaw, Colorado State University, Bugwood.org
Larva of a multicolored Asian lady beetle feeding on aphids. Note the coloration and presence of spikes. Image credits: Whitney Cranshaw, Colorado State University, Bugwood.org
Conservation
Lady beetles are voracious feeders when prey is abundant, making them valuable natural enemies. Lady beetles may be tolerant to some insecticides, but this is highly dependent on species and prior exposure of the resident population to a given insecticide.
When collecting lady beetles for redistribution, they should be handled gently and placed in groups at the base of plants. It is recommended that hibernating adults not be disturbed since they are more susceptible to predation. Some lady beetles supplement their diet with nectar and pollen. Therefore, incorporating flowering plants in the vicinity of a crop may help attract these beneficial insects.
CSU Extension Fact Sheet
Download or view the CSU Extension’s PDF fact sheet for your reference.
References
Cannon, C., M. Murray, R. Patterson, and K. Wagner. (n.d.). Available https://extension.usu.edu/pests/files/pubs/Beneficial-Insects-of-Utah-ID-Guide.pdf
Cornell University. (n.d.). Lady Beetles. Cornell University – College of Agriculture and Life Sciences. Available https://biocontrol.entomology.cornell.edu/predators/ladybeetles.php