A Guest for the Winter – Asian Ladybug

By LBL_AdminOn November 14, 2014January 22, 2020

Submitted by Brian Truskey, Communications Apprentice at Land Between The Lakes

It’s that time of year again, when many of our homes play host to a familiar visitor, the ladybug. Or more specifically, the Asian lady beetle. Though most ladybugs make their homes outdoors, this often uninvited guest will happily bunk with you over the winter.

What’s in a name?

Laybugs, also known as Ladybirds or Ladybird beetles, were named after the Virgin Mary. “Beetle of our Lady,” the precursor to many of the names we use today, was used as far back as 1699. Some sources claim that the various names may have even older roots.

One story attributes the name Ladybug, or originally “Our Lady’s Bug” to a miracle during the middle ages. As the story goes, small insects or aphids were eating all of the crops. The people petitioned for intervention, and were answered by a small swarm of spotted insects that ate up the pests. Afterward, the helpful little bugs were given their new name. More information on that particular story can be found here: http://catholicism.org/our-ladys-bug.html

Mass of Asian Beetles, Photo from University of Kentucky College of Agriculture, Food, and Environment

Telling the difference

With around 5,000 species of ladybug known through the world, and more than 400 in North America, it might be difficult to tell the difference. So, how can we tell them apart? There are several characteristics you can look for when identifying ladybugs. The numbers of spots, for example, can vary by species. Contrary to some beliefs, the number of spots do not determine how old a ladybug is. Spots do, however, fade with age.

The Asian ladybug, or Harmonia axyridis, is the variety you will most likely find in your house in late fall, winter, and early spring. They are oval, convex, about ¼ in long, with color varying from tan to orange to red, and can have many or no spots. Females are more likely to have more spots, while males tend to have few or no spots. Around16 spots is fairly common. You can also look for a distinct “M” or “W” shape on the white area by the base of their head.

Another non-indigenous European variety, the seven spotted ladybug, or Coccinella septempunctata, will be found eating many of the same insect pests and on the same plants that you find the Asian Ladybug on. They can be differentiated from the Asian ladybug by their spots. They have three spots on each elytra, or shell-like wing, with a seventh spot in the middle, often near the head.

You can find several handy guides to identifying ladybugs on the Internet, such as this one from the Natural History Museum. www.nhm.org/site/activities-programs/citizen-science/lost-ladybug-project/identifying-ladybugs

Asian Beetles vary in color. Most notably, they have a whitish area on the head with an 'M' shape. Photo from University of Kentucky College of Agriculture, Food, and Environment — Asian Beetles vary in color. Most notably, they have a whitish area on the head with an ‘M’ shape. Photo from University of Kentucky College of Agriculture, Food, and Environment

Where did they come from and why are they in my house?

The Asian lady beetle is not native to the United States. They were imported to the United states in 1916. The first notable populations weren’t reported until 1988 in Louisiana, however. Other accidental introductions from them hitching rides on cargo vessels may also be a contributing factor.

Sources conflict somewhat as to the reason Asian ladybugs are attracted to our homes. Some say that they are attracted to light colors, while others say they are attracted to contrasting light and dark colors, and mistake such patterns for those of their natural wintering habitats. These ladybugs also like to congregate on the sunny sides of buildings, and may avoid homes that are shaded from the afternoon sun.

After they mistake your house for a good wintering spot, and enjoy a bit of evening sunning, they crawl under the siding, or into the attic, where they winter. Many times they crawl in deeper, or get lost. At night when they see the light in your house they head toward it and emerge into your home. Like many bugs and beetles, they are attracted to light. This is especially common in late winter and early spring when things begin to warm up and they are ready to head back out. If they get turned around after their long sleep, they may just find their way into your house rather than back outside.

Asian Beetle on Brian Truskey, Photo by Kasey Johnson

The good, the bad, the buggy

Asian lady beetles are a mixed blessing. While they can bite if held, and may leave stains if disturbed, they are also beneficial.

The good. Asian ladybugs eat a variety of aphids that feed on trees and crops, especially soybeans. An adult ladybug can eat as many as 5,000 aphids in their lifetime. The work they do helps keep other plants healthy, which in turn reduces the amount of pesticides that farmers and gardeners have to use.

The bad. Their mouths have little pincers that they use to eat insects such as aphids, and they can bite or pinch people when disturbed. Often it is little more than a pin prick and not usually serious. Some research also suggests that they may cause allergies or allergy like symptoms in some people.

These ladybugs also leave behind a yellow fluid with an unpleasant odor when disturbed. This is known as “reflexive bleeding” and is a defense mechanism that discourages birds and other predators from eating them. The “blood” they leave behind has a strong odor and can stain certain surfaces. If you get some of it on you, it’s probably best to wash it off.

Ladybugs do not damage structures like some insect pests do, nor do they bother clothing or food inside the home. They also will not breed indoors, despite what may seem like growing numbers. It is more likely the ones hibernating in the walls are simply waking up and heading toward the light inside the house. Early in the season it could be that more are making their way toward your home if they have mistaken the outside coloration for a good wintering habitat.

Asian Beetles on Brian Truskey, Photo by Kasey Johnson

How to best handle the problem

The best way to keep ladybugs from becoming a problem is prevention. They like to hibernate inside the walls, and sometimes accidentally go deeper inside your home when they are seeking a way out. Filling in the cracks and holes they climb through eliminates the problem before it begins. Caulk or other substances that fill in the gaps and crevices can be used. This method doesn’t always work, especially in older homes with lots of nooks and crannies, or may not be practical in some instances.

If you don’t have many of these visitors, it may be best to simply leave them be. In the spring time they will leave on their own, and by not disturbing them you can avoid the staining and the odor. If that’s not a viable option for you, it may be time to get out the vacuum cleaner.

A vacuum or shop vac should work. Using a shop vac, or vacuum without moving brushes that they have to pass through will minimize the harm to the ladybugs if your goal is to remove them with minimal harm. Once you’re done vacuuming them up, remember to empty the bag outside to avoid releasing them into the house again.

There are also a variety of ladybug traps available that use lights or black lights to attract and capture them. After they are captured in the traps, simply release them outside.

Spraying is another option, although it may have limited success, especially if they are already inside your home. Sprays can also be washed away by rain, and some chemicals are neutralized by the sun. In any case, check your local and state laws on which sprays and pesticides can be used, and always follow safety instructions. Spraying may be most effective when done early and often to keep them from entering your home in the first place, especially if filling in the gaps is not an option.

Folklore

Variations of the children’s rhyme, “Ladybird, Ladybird, fly away home! Your house is on fire, Your children do roam. Except little Ann, who sits in a pan Weaving gold laces as fast as she can” have been attributed as a warning to ladybugs. It is in reference to the burning of hop plants, and warning the adult ladybugs to escape. The young grubs still shedding their skin, or “little Ann” still in her “gold lace,” were unable to flee from the fire. More on this story can be found at http://campus.udayton.edu/mary/questions/ladybug.html

Some also believe that the ladybug is good luck. A few of the common beliefs are that seeing a ladybug will bring good luck, good weather, love, or that killing one will bring bad luck. The latter of which was possibly propagated by farmers in an effort to help protect the little bug that kept their crops safe from harmful insects such as aphids.

If you’d like to know more about ladybugs, visit the references below.