Asian Lady Beetles

Asian Lady Beetles

It was quite the coincidence that you started noticing those tiny, oval-shaped beetles clustering at the corners of your windows just as the autumn season set in. That’s because multicolored Asian lady beetles like warm, sunny sites like southwest-facing buildings and find themselves drawn to your home during this time. Although these lady beetles are generally beneficial in controlling pests like aphids, you might not appreciate their welcoming party. As warmth and light seem to guide their behavior, understanding their habits could help you manage this occasional invasion.

Things to know about Asian Lady Beetles

Asian lady beetles, known for their oval bodies and multicolored patterns, are a common sight in fields and gardens, where they consume aphids and other soft-bodied insects. These beneficial predators have been intentionally introduced to various regions to control insect pests in trees and agricultural crops. As native inhabitants of Eastern Asia, they’ve adapted to inhabit a broader range of areas worldwide.

There are three key facts to keep in mind regarding Asian lady beetles:

1. Variety of Colors: These beetles occur in various colors, including pale yellow-orange to bright red-orange, with or without black spots on their wing covers.
2. Life Cycle: The life cycle includes egg, larva, pupa, and adult stages, with multiple generations per year. Adults can live up to two to three years in ideal conditions.
3. Overwintering: Beetles spend the winter in protected sites, often congregating around buildings with light-colored exteriors, especially on the southwest sides, which receive more afternoon sun.

Understanding these characteristics can help you better appreciate and manage the presence of these helpful insects in your environment.

Dangerous or not

While they’re beneficial to gardens, multicolored Asian lady beetles can also cause some issues, particularly during the fall when they invade homes in search of overwintering sites.

One of the primary concerns about these insects is whether they’re dangerous to humans and pets. Generally, Asian lady beetles aren’t harmful. They don’t bite aggressively and aren’t known to spread diseases. However, they may bite defensively when handled, which can cause minor skin irritation in some individuals. Their bites aren’t serious and are avoided by wearing gloves when handling them.

In terms of allergic reactions, some people may experience skin irritation due to the beetles’ secretions. The main problem with these beetle aggregations is that they emit an unpleasant odor and can leave stains on fabrics when agitated or crushed.

Effects on humans

In rare instances, handling multicolored Asian lady beetles can cause allergic reactions, such as rhinoconjunctivitis and mild skin irritation, primarily due to the defense secretion they release when disturbed. While these reactions are mild and temporary, they can be annoying.

Here are some key points to know about these reactions:

Key Issues with Allergic Reactions:

1. Rhinoconjunctivitis: Asian lady beetles can trigger severe allergic reactions such as rhinoconjunctivitis, which involves the eyes and nose.
2. Skin Irritation: Handling these beetles can cause mild skin irritation, which is usually temporary.
3. Breathing Problems: In rare cases, some people may experience breathing issues or asthma-related symptoms when exposed to these beetles.

If you experience any of these symptoms, it’s essential to take care when handling these insects.

Wear protective gloves and wash your hands thoroughly after handling them to minimize exposure to their secretions.

Always prioritize your health when interacting with Asian lady beetles.

Insect bite

In rare cases, these lady beetles can bite, causing minor discomfort. When they do, it may feel like a pinching sensation, but it isn’t venereal. These bites are generally harmless and not severe enough to spread diseases. However, some individuals might react with allergies or skin irritation.

It’s advisable to avoid touching your eyes after handling these lady beetles to minimize irritation. While they might bite, the real nuisance comes from their defensive secretions. When bothered, they release a strong-smelling yellow fluid that can stain surfaces. This reflex bleeding helps deter predators, but it can lead to significant indoor issues during winter when they cluster around buildings in large numbers.

To manage these incidents, focus on preventive measures like sealing entry points, as chemical treatments are largely ineffective once they’re inside. Keeping your living spaces clean and free from debris will also help eliminate any potential hiding spots.

Bite effects

Experience shows that the bites of these multi-colored beetles can result in some discomfort. The bite feels like a pinprick, and while it isn’t serious, it can cause minor short-lived discomfort. These bites can break human skin but are generally not serious. Very few people have reported allergic reactions to the bites.

In most cases, the bite will result in some redness and swelling. This is due to the beetle’s saliva, which leads to an allergic response within the body. It’s important to keep the bite clean and avoid scratching the area to minimize the risk of infection. It’s also advisable to wash your hands thoroughly after handling the beetles.

If you get bitten, you might need to wash the area with soap and water. If the bite becomes infected or you experience persistent discomfort, seek medical attention. It’s essential to remember that these bites are generally not serious and will heal quickly.

How to treat

To treat bites from the multicolored Asian lady beetle, start by washing the affected area gently with soap and water to minimize the risk of infection. Although rarely serious, these bites may cause discomfort and minor inflammation.

Anti-itch creams or hydrocortisone cream can be applied to reduce itching and swelling.

Cold compresses can help alleviate any itching or inflammation.

Antihistamines can be taken to alleviate allergic reactions, but only under the guidance of a medical professional.

If you experience severe symptoms such as difficulty breathing or swelling in the face, seek medical attention.

Causes

The multicolored Asian lady beetle infestation in buildings is likely caused by the insects’ natural instinct to overwinter in protected areas. This instinct drives them to seek out warm and secure locations to avoid the harsh winter environment. As the weather cools, these beetles begin to aggregate on buildings, particularly on south-facing walls that receive direct sunlight.

The main causes of Asian lady beetle infestations in homes and buildings can be summarized as follows:

1. Overwintering Instinct: Asian lady beetles seek protected areas to shield them from cold temperatures and harsh weather conditions.
2. Attracted to Light and Heat: These beetles are drawn to the warmth and light emitted by buildings, leading them to congregate on walls and windows.
3. Entry Through Small Openings: Asian lady beetles can fit through tiny cracks and crevices, allowing them to enter buildings and cause infestations.

Signs of

Asian lady beetles announce their presence with a mass gathering of thousands on building surfaces, particularly the west or southwest sides, marking their search for overwintering sites. This influx of beetles often takes place during autumn when the weather begins to cool.

The likeliest buildings to be targeted are those with light-colored exteriors, tree-dwelling nearby, or located near wooded areas. Houses receiving direct sunlight, especially on the southwest side, are particularly susceptible to these aggregations.

Signs to Look Out For

• Visual Overload: Thousands of lady beetles swarming on building surfaces, walls, and windows, making your home their winter haven.
• Unpleasant Odor: A foul-smelling yellow fluid released by the beetles as a defense mechanism, which can stain surfaces and irritate those with allergies.
• Uninvited Guests: Beetles venturing into living areas, causing discomfort and nuisance due to their sheer numbers and activity.

Keep in mind that while these signs may be unsettling, the beetles are primarily harmless and don’t pose significant health risks.

Life cycle and reproduction

You’ll find that the life cycle of these lady beetles involves four distinct stages: egg, larval, pupal, and adult.

During the egg stage, females typically lay clusters of yellow, oval-shaped eggs on the undersides of leaves, providing the young with a food source once they hatch. These eggs incubate for about three to five days before hatching into larvae.

As larvae, they go through four instars, with the final instar resembling a small, alligator-like insect. Throughout this stage, they feed on aphids and other soft-bodied insects.

The pupal stage follows, where the larvae enter a cocoon-like condition, usually lasting five days.

After emergence, the beetles enter the adult stage. Adult Asian lady beetles are oval, convex, and about a quarter-inch long. They can vary from tan to orange to red in color and often have several black spots on their wing covers.

Most beetles also have a small, dark ‘M’ or ‘W’-shaped marking on the whitish area behind the head. This stage typically lasts anywhere from a month to three years, with most beetles living for one to three months.

Attracted to

Areas with lighter colors, such as whites, grays, and yellows, attract Asian lady beetles, which could lead them to congregate on the southwest sides of houses where they’re exposed to more sunlight. This preference for light colors often means that these beetles are more likely to infest homes and other buildings, as they seek out protected areas to overwinter.

Attracting Factors:

1. Lighter Colors: Light-colored exterior surfaces, such as white or yellow, tend to draw Asian lady beetles.
2. Sunlight Exposure: These beetles are attracted to southwest-facing sides of buildings that receive direct sunlight.
3. Contrasting Features: Homes with contrasting light-dark features, like dark shutters on a light background, are more likely to attract the beetles.

Asian lady beetles are often found on building sides that are exposed to more sunlight, so knowing these attracting factors can help in managing and preventing infestations.

Behavior

As autumn approaches, these lady beetles leave their summer feeding sites in yards, fields, and forests to seek protected places for overwintering. They’re attracted to illuminated surfaces and congregate on light-colored buildings, particularly those with contrasting light-dark features like dark shutters on light backgrounds or light shutters on dark backgrounds.

This behavior is seen even in their native Japan, where they fly to south-facing rock cliffs and outcroppings to overwinter.

To understand this behavior better, consider the following key points:

1. Timing: The beetles typically migrate to buildings from September to November, peaking in October in Kentucky.
2. Location: Sunnier, southwest-facing sides of buildings are more attractive to the beetles due to the afternoon sun.
3. Habitat: Houses in forested areas and those with cracks and openings are more prone to infestation as the beetles seek protected sites to hibernate.

Understanding these behavioral patterns can help you prepare your home and take preventative measures to minimize the nuisance caused by these lady beetles during the winter season.

Natural predators and parasites

In the United States, several natural predators and parasites play an essential role in regulating the multicolored Asian lady beetle population. One of the key parasites is a fungus that infects the beetles, particularly in central Kentucky, where it can be lethal in some cases. Additionally, tiny wasps and flies also parasitize a small percentage of the beetle population.

Lady beetles have a unique defense mechanism, secreting a foul-smelling fluid from their leg joints when disturbed, which helps deter predators. Moreover, certain natural enemies may target specific stages of the beetle’s life cycle. For example, the pupal stage is often vulnerable to predators, as it remains attached to vegetation by its molted skin.

Despite these natural controls, the multicolored Asian lady beetle remains an important biological control agent, particularly in managing aphid populations.

Best Killer

One of the most effective predators of the multicolored Asian lady beetle is the praying mantis. This insect is known for its stealthy and cunning nature, making it an ideal hunter. The praying mantis’s camouflage abilities and long, slender forelegs allow it to remain hidden and then quickly capture prey.

Here are some reasons why the praying mantis is so effective:

1. Stealthy Nature: Praying mantises are masters of camouflage. They can remain still and blend into their surroundings, allowing them to ambush unsuspecting lady beetles.
2. Long Forelegs: The slender, elongated forelegs of the praying mantis provide an ideal mechanism for catching and holding onto prey.
3. Patience: Praying mantises are known for their incredible patience. They’ll wait for long periods, even days, for the perfect moment to strike.

The praying mantis is just one example of the natural predators that target the multicolored Asian lady beetle.

Understanding these predators can help us better manage the lady beetle population and minimize their nuisance.

Control Asian Lady Beetles

To effectively control Asian lady beetles, a combination of proactive measures, physical removal, and chemical treatments is recommended. Here are some of the best strategies:

Proactive Measures

1. Seal Entry Points: Prevent beetles from entering your home by sealing gaps and cracks around windows, doors, siding, chimneys, and other potential entry points [9][13].
2. Repair Screens: Ensure that window and door screens are intact and free of holes.

Physical Removal

1. Vacuuming: Use a vacuum with a HEPA filter to remove beetles. Be sure to empty the vacuum bag or canister outdoors to prevent odors .
2. Broom and Dustpan: Sweep beetles into a dustpan and release them outside.
3. Insect Light Traps: Place these traps in dark areas where beetles are likely to gather, such as attics.

Chemical Treatments

1. Barrier Treatments: Apply insecticides around the perimeter of your home. Products like Supreme IT Insecticide are effective for this purpose. Spray 3 feet up and 3 feet out from the foundation, targeting areas like window frames, door frames, and other entry points.
2. Indoor Treatments: Use products like Pyrid Aerosol and D-Fense Dust in cracks, crevices, and other areas where beetles hide indoors.
3. Comprehensive Kits: Consider using a control kit that includes multiple products for both indoor and outdoor use. The Asian Lady Beetle Control Kit from ePestControl includes Onslaught FastCap Concentrate, Stuffit Copper Wool, and CimeXa Dust, which can be used to treat various areas effectively .

Professional Help

If the infestation is severe, contacting a pest management professional (PMP) can provide tailored solutions, including the application of insecticides at optimal times and comprehensive pest-proofing services.

By combining these methods, you can effectively manage and reduce the presence of Asian lady beetles in your home.