Ladybugs (coccinellidae) are a welcome addition to any garden because they eat the small bugs that can destroy plants. In the late 1980s, the Asian beetle (Harmonia axyridis) was introduced into the United States to further help control the pest population. Although ladybugs and Asian beetles look very similar, there are differences between them.
Asian Beetle Appearance
The Asian beetle varies in color, ranging from pale orange to deep red. The number of spots on the backs of Asian beetles also varies, with some beetles having no spots and others as many as 19. An Asian beetle has a distinguishing mark between its back and head that looks like a "W" or an "M," depending on which way you view the bug.
The ladybug is the beetle that most people are familiar with and for which the Asian beetle is often mistaken. Ladybugs are dark red in color, with little variation between each individual bug. A true ladybug also features a more uniform pattern of dots on its back, and it lacks the "W" or "M" shape behind its head. A ladybug's shell can be either rounded or oval in shape.
Asian Beetle Features
While the Asian beetle is a helpful biological insect control, they themselves are also considered pests. Once believed to bite people, Asian beetles don't technically bite. However, when the beetle searches your hand for moisture or food, it may inflict a sharp pinching or scraping sensation. Asian beetles are also likely to invade your home. They often congregate on the sunny side of a house, entering through small cracks around windows or siding when the weather turns chilly.
Ladybugs are sometimes called a gardener's best friend. They voraciously eat aphids and other small bugs that are harmful to garden plants. A ladybug can consume up to 5,000 aphids during its short life span -- even in the larval stage a ladybug feeds on small insects. The ladybug's red color represents a warning that makes it unattractive to potential predators, as does the foul substance that is secreted from its legs. True ladybugs, which are thought to bring good luck, exist in fewer numbers than Asian beetles.