Spot the Difference: Ladybug and Asian Beetle

Ladybugs are beloved garden allies that keep pests in check, but their look-alike, the invasive Asian lady beetle, often sneak indoors during fall and spring, and can threaten ladybug populations. In this blog, we’ll help you tell them apart so you can protect both your home and beneficial ladybugs from this aggressive impostor.

What’s the Difference Between A Ladybug and an Asian Lady Beetle?

Common ladybugs (generally species in the Coccinellidae family) and Asian lady beetles (Harmonia axyridis) share some similarities in their general appearance but also exhibit distinct physical characteristics. 

Color

Common ladybugs are bright red or orange with a consistent tone, giving them their familiar, cheerful look. Asian lady beetles vary widely in color, from pale yellow-orange to deep red, which often leads people to mistake them for different species.

Size

Ladybugs are smaller, usually around 5–7 millimeters in length. Asian lady beetles are slightly larger at 5.5–8.5 millimeters, with a more elongated oval body that makes them appear flatter when viewed from the side.

Spots

Native ladybugs typically display seven distinct, evenly spaced black spots. Asian lady beetles can have anywhere from zero to nineteen irregular spots, or none at all, making their appearance less uniform and often more confusing to identify.

Pronotum Markings

The pronotum, the shield-like area behind the head, differs between species. Ladybugs show a mostly black area with small white “cheeks,” while Asian lady beetles feature a bold black “M” or “W” pattern on a white background.

Body Shape

Ladybugs have a rounded, dome-like body that looks smooth and compact. Asian lady beetles appear more oval and slightly flattened, which helps them slip through small crevices when seeking shelter indoors.

Behavior

Ladybugs are gentle and rarely interact with humans, preferring to stay outdoors in gardens. Asian lady beetles, however, can bite when provoked and tend to gather in large groups, especially inside homes during seasonal shifts.

Seasonal Activity

Ladybugs remain active outdoors during warm months and retreat naturally in cooler weather. Asian lady beetles, seeking warmth, invade homes in fall and reappear in spring, often clustering on sunny walls and windows.

Odor and Secretions

When disturbed, ladybugs produce little to no odor. Asian lady beetles secrete a yellow, foul-smelling fluid that can stain surfaces and irritate skin, which is a key sign of their presence indoors.

Ecological Role

Ladybugs are valuable pest controllers that protect gardens by feeding on aphids and other soft-bodied insects. Asian lady beetles also eat pests but compete with native ladybugs for food and habitat, disrupting local ecosystems.

Ladybug vs Asian Beetle Comparison Chart

Are Asian Lady Beetles Harmful to Plants?

Asian lady beetles can potentially harm plants, especially when present in large numbers. 

Indirect Plant & Fruit Damage

While Asian lady beetles mainly feed on aphids and other soft-bodied insects, they may turn to fruit when aphid sources are scarce. Their abundance can also cause indirect damage, as their search for prey sometimes harms plant tissues. During colder months, their tendency to seek indoor shelter can also create nuisances and occasional damage to ornamental plants or crops.

Are Asian Lady Beetles Harmful to Ladybugs?

Asian lady beetles (Harmonia axyridis) pose several threats to common ladybugs (Coccinellidae species) when they coexist in the same habitats. 

Competition for Resources

One significant threat is direct competition for resources such as food and overwintering sites. Asian lady beetles are known for their aggressive behavior, often outcompeting native ladybugs for prey like aphids and other soft-bodied insects. This competition can reduce the available food sources for common ladybugs, potentially impacting their survival and reproductive success.

Microsporidian Parasites

Another concern is the transmission of microsporidian parasites, specifically Nosema spp., by Asian lady beetles. These parasites can infect and weaken native ladybugs, affecting their health and ability to reproduce. 

Adaptation to Ecosystems

Furthermore, Asian lady beetles are generally more adaptable to a wide range of environmental conditions and habitats compared to many native ladybugs, giving them a competitive edge in colonizing and occupying shared ecosystems.

How Did Asian Lady Beetles Get to the US?

The Asian lady beetle was originally introduced into the United States around 1916 as a biological control agent to manage aphid populations in agricultural settings. However, it wasn't until 1988 that these beetles became established in North America, particularly in the southeastern United States. Since then, Asian lady beetles have rapidly spread across the continent, becoming an invasive species with significant ecological and economic impacts.

 How to Get Rid of Asian Lady Beetles

• Physical Removal: Use a vacuum cleaner to remove Asian lady beetles from inside your home, then move outside and carefully empty the contents into a sealed trash bag.

• Seal All Entry Points: Close any cracks or gaps around doors, siding, windows, screens, etc. to prevent interior access.

• Create a Barrier Around Your Home: Trim vegetation around the perimeter of your home to store wood at least 15 feet away.

• Use Natural Repellents: Spray citrus oil or citronella to repel Asian lady beetles.

• Turn Off Outside Lights at Night: Limit outdoor illumination by using motion-activated fixtures and cooler, low-heat bulbs.

Explore Ladybug Metamorphosis with Insect Lore

Now that you know the difference between beneficial ladybugs and invasive Asian lady beetles, continue your insect adventure! Explore our Ladybug Kits!