Ladybugs are also known as ladybirds and ladybird beetles, but the common name preferred by entomologists is lady beetle. Lady beetles play a critical role as beneficial predators of soft-bodied arthropods, such as aphids and scales. Today, multi-colored Asian lady beetles are considered a nuisance pest, particularly when they invade in large numbers in the fall.
WHAT ARE MULTI-COLORED ASIAN LADY BEETLES?
A native of eastern Asia, the multi-colored Asian lady beetle (Harmonia axyridis) was introduced into the United States by the U.S. Department of Agriculture as a biological control agent in California in 1916.
Multi-colored Asian lady beetles were never deliberately released into Minnesota. They migrated into our area from nearby states.
Multi-colored Asian lady beetles were first sighted in Minnesota in November, 1994.
Multi-colored Asian lady beetles are now well established throughout the U.S. and spread into Canada in 1994
The multi-colored Asian lady beetle has been described as the most invasive lady beetle on Earth.
In North America alone, multi-colored Asian lady beetles have been found feeding on 36 different species of aphids and other pests, and have greatly reduced the number of native lady beetles in North America.
WHAT'S THE DIFFERENCE BETWEEN MULTI-COLORED ASIAN LADY BEETLES AND NATIVE LADY BEETLES?
The most important distinction between native lady beetles and multi-colored Asian lady beetles is that Asian lady beetles invade a structure to spend the winter. The native lady beetles on the other hand, like it a little chilly and will hide in cracks and crevices outdoors until the spring.
As a result, Asian lady beetles are more likely to swarm your house and invade wall voids in your home through cracks and crevices.
WHY ARE MULTI-COLORED ASIAN LADY BEETLES IN MY HOUSE?
The most obvious sign of a nuisance infestation is the appearance of large numbers of multi-colored Asian lady beetles on the outside surfaces of structures; congregated in the cracks and gaps of the siding, and inside the building on the walls and ceilings.
Between late September and late October, as the cold weather approaches, food availability often become challenging for many insects. Additionally, environmental cues, such as temperature, daylight, and relative humidity, along with species-specific developmental factors indicate its time for multi-colored Asian lady beetles to find over wintering sites.
Some researchers believe that because in their native habitat of Asia adult multi-colored Asian lady beetles habitually seek cracks and crevices in cliff faces to hibernate, multi-colored Asian lady beetles seek to overwinter in and around buildings in the U.S.
Other studies indicate multi-colored Asian lady beetles are attracted to contrast, such as shadows or dark shutters, etc., which loosely resembles the white cliff faces of their native habitats in Asia.
At overwintering sites, multi-colored Asian lady beetles congregate on the sunlit south and west parts of the building
Multi-colored Asian lady beetles will seek out sheltered areas to overwinter, such as cracks or crevices in walls, under siding, roofs, overhangs, or voids in attics, crawlspaces, empty roof spaces, vent openings, and ceilings.
Sunny and warm winter days (around 50°F) trigger the over-wintering lady beetles to wake up and move in and around the house.
Obviously, any insects noted indoors during the winter are not coming in from the outside; they are coming from within the structure.
CAN MY HOUSE BE DAMAGED BY MULTI-COLORED ASIAN LADY BEETLES?
Generally, not. Asian lady beetles do not eat fabric, plants, paper, or human or pet food.
Asian lady beetles do not damage the structure of your home.
However, when they sense danger Asian lady beetles release a small amount of their fluid which is yellow and smells, leaving yellow markings on your walls and staining light colored surfaces.
Moreover, dead Asian lady beetles inside wall voids, cracks and crevices attract dermestid beetles, such as hide beetles, larder beetles, carpet beetles. They also attract ants, especially carpenter ants.
ARE MULTI-COLORED ASIAN LADY BEETLES DANGEROUS?
Multi-colored Asian lady beetles cannot sting and Asian lady beetles are not known to carry any disease.
However contrary to popular belief, multi-colored Asian lady beetles can and do pinch humans when handled.
The bite of multi-colored Asian lady beetles is similar to a pinch and no blood meal is taken from the person being bitten.
Multi-colored Asian lady beetles are a source of allergic reactions that range from sneezing to asthma depending on the individual's sensitivity.
Some individuals experience rhino conjunctivitis (sinus irritations) and mild skin irritations as allergic reactions to the multi-colored Asian lady beetles' yellow defensive excretions.
WHAT DO MULTI-COLORED ASIAN LADY BEETLES LOOK LIKE?
Multi-colored Asian lady beetles are slightly larger than native lady beetles, with adults measuring 9/32" in length and 7/32" wide.
Unlike most lady beetles, multi-colored Asian lady beetle adults have various color patterns, such as, orange with black spots, red with black spots, yellow with black spots or solid orange with no black spots
Multi-colored Asian lady beetles' spots, which can vary in size and pattern, number from no spots to as many as nineteen.
Adult multi-colored Asian lady beetles have a pattern of W or M-shaped mark behind its head.
Multi-colored Asian lady beetles' eggs, which are laid upright in clusters of about twenty, are oval and yellow.
The larvae are blue to black with two orange stripes, and resemble alligators with rows of small, spine protuberances on their bodies and legs protruding from their sides.
WHAT DO LADY BEETLES EAT?
Both adult and larvae lady beetles are predators.
Almost all lady beetles feed on soft-bodied insects, such as white flies, mites, and aphids.
Gardeners welcome lady beetles with open arms, knowing they will eat plant pests by the hundreds.
Adult lady beetles consume about 90-270 aphids per day, while larvae consume 600-1200 aphids during their development.
HOW DO LADY BEETLES PROTECT THEMSELVES FROM THEIR NATURAL PREDATORS?
In nature, red, yellow and black are colors that warn predators that the insect they are about to eat might be poisonous, taste bad, or have the ability to defend itself against the predators.
Lady beetles protect themselves by pulling their legs up "turtle-style" and playing dead.
Lady beetles also typically release a small amount of stinky liquid from their legs. The bad smell usually deters predators
WHAT IS THE LIFECYCLE OF MULTI-COLORED ASIAN LADY BEETLES?
Multi-colored Asian lady beetles undergo a complete metamorphosis, in which there are four stages: adults, eggs, larvae, and pupae.
Female multi-colored Asian lady beetles lay eggs in clusters of 20-30 eggs on the underside of leaves, usually near aphid colonies.
Eggs hatch in 3-5 days.
Multi-colored Asian lady beetle larvae develop through four instars within 11 days, molting their outer skins.
The larvae resemble tiny black alligators.
Pupae stage usually lasts 5 days.
The life cycle from egg to adult requires about two to four weeks.
In the U.S., there are two generations of multicolored Asian lady beetles per year.
Healthy multi-colored Asian lady beetles can live up to 3 years depending on the temperature and food availability.
15 INTERESTING FACTS ABOUT LADY BEETLES:
Ladybugs aren't really bugs at all, they're beetles!
Entomologically speaking, the term bug applies to insects of the order Hemiptera. Ladybugs belong to the order Coleoptera, or beetles.
There are over 5000 species of lady beetles of which 400 are native to North America alone.
Although multi-colored Asian lady beetles are considered nuisance fall invaders in most North American homes, in some cultures the presence of lady beetles in a house is considered a symbol of good luck.
In Sweden, a lady beetle walking across the hand of a single girl indicates that it is measuring for wedding gloves.
In nature, the population of multi-colored Asian lady beetles consists of 50% males and 50% females. However, inside houses, it has been estimated that 66% of multi-colored Asian lady beetles are females and 34% are males.
Europeans have called these dome-backed beetles by the name ladybirds, or ladybird beetles, for over 500 years. In America, the name ladybird was replaced by ladybug.
The "lady" in ladybug refers to the Virgin Mary.
In Germany, these insects go by the name Marienkafer, which means Mary beetles.
There are different versions of how these beetles came to be known as ladybugs or lady beetles, but one of the most popular versions is that during the Middle Ages crops in Europe were plagued by pests, so the farmers began praying to the Blessed Lady, the Virgin Mary. Soon, the farmers started seeing lady beetles in their fields, and the crops were miraculously saved from the pests. They associated their good fortune with the black and red beetles, and so began calling them lady beetles.
Scientists believe lady beetles may lay both fertile and infertile eggs. The infertile eggs provide a ready source of food for the young larvae which hatch from the fertile eggs.
Female lady beetles will lay an increased number of infertile eggs in harsh environments to give her babies a better chance of surviving.
Lady beetles practice cannibalism. If food is scarce, lady beetles will eat soft-bodied, newly emerged adults, recently molted larvae, eggs, or pupae in order to survive.
You cannot tell a lady beetle's age by counting its spots.
Lady beetles taste and smell with their antennae.
Ladybugs Resource Page
"Everyone was very impressed with the work Adam's does, expecially with their commitment to helping needy families who are faced with bed bug infestations. Many of them have asked me to pass along... " Read More
Professional Pest Management Alliance Logo