The Asian lady beetle is an oval-shaped beetle that measures between 4.8 and 7.5 mm long. It is one of the largest species of ladybugs that can be seen in Quebec. Its elytra, which covers a pair of membranous wings allowing flight, present a great variety of coloration. The hue of these hardened wings varies from yellow to black, through orange and red. There is a variable number of points, ranging from zero to twenty. In Canada, the orange form marked with 19 black dots dominates. The head, antennae and mouthparts of this ladybug are usually pale yellow. The pronotum, which covers the first part of the thorax, just behind the head, bears two pale false eyes shaped like footballs. There are also black spots that often form an M-shaped mask. The female is slightly larger than the male.
DO NOT WAIT
WE RESPOND TO
FREQUENTLY ASKED QUESTIONS
ALL ABOUT LADYBUGS
Why are there so many ladybugs in the house?
There are several reasons why you may notice an increased presence of ladybugs in your home:
- Seek shelter: Ladybugs seek a warm, safe place to hibernate during the winter months. They are attracted to light surfaces exposed to the sun to warm up.
- Food source: If your home is infested with other smaller insects, such as aphids, this can attract ladybugs to feed on them.
- Climate: Changes in climate, such as a sudden drop in temperature, can cause ladybugs to seek refuge indoors.
- Easy access: Ladybugs can enter through small cracks or openings in walls, windows or doors.
- Pheromones: Ladybugs emit pheromones to signal a safe place to hibernate to other ladybugs. If ladybugs have already hibernated in your home, their pheromones may attract other ladybugs.
Remember that although they can be a nuisance, ladybugs are beneficial to the ecosystem because they eat other pests.
What attracts ladybugs?
Ladybugs are attracted to a number of factors that include:
- Aphids and mealy bugs: These two types of insects are preferred prey for ladybugs. If your garden, or home, is infested with aphids or mealy bugs, ladybugs can be attracted in large numbers.
- Light: Ladybugs are attracted to light, especially in the fall when they are seeking shelter to hibernate. They may be attracted to the lights in your home.
- Warmth: Ladybugs seek warm places to hibernate. This is why they may be attracted to heated homes and buildings during the fall and winter.
- Light surfaces: Ladybugs are often attracted to light surfaces, especially those exposed to the sun.
- Pheromones: If a ladybug has already found a good place to hibernate (such as your home), it may release pheromones to signal to other ladybugs that the place is safe and appropriate. This is one reason why you may see an accumulation of ladybugs in one place.
It’s important to note that while they can be annoying in large numbers, ladybugs are valuable allies in your garden because of their appetite for aphids and other pests.
Why shouldn’t ladybugs be killed?
There are several reasons why killing ladybugs is not recommended:
- Biological control: Ladybugs play an important role in regulating insect pest populations, including aphids, mealybugs and mites. A single ladybug can consume up to 5,000 aphids in its lifetime, making it a valuable ally in protecting your plants.
- Protection of biodiversity: Ladybirds are part of the ecosystem and contribute to its biodiversity. Eliminating them could have unintended consequences for other species and the overall balance of the ecosystem.
- Natural Regulation: Ladybug populations are generally regulated naturally by predators, parasites and food availability. If you see a sudden increase in their numbers, it may be a sign of a population explosion of aphids or other insects they feed on.
- Not dangerous: Ladybugs are not dangerous to humans. They do not sting and do not spread diseases.
If you find ladybugs in your home and they become a nuisance, it’s best to gently capture them and release them outside rather than kill them.
How do you know if it’s an Asian ladybug?
The Asian lady beetle, also known by the scientific name Harmonia axyridis, is a species of lady beetle that can be identified by several specific characteristics:
- Size: Asian ladybugs are slightly larger than most other ladybug species. They are usually between 5.5 and 8.5 millimetres long.
- Colour and pattern: Their colour varies from yellow to black to red. The number of points on their back can vary from 0 to 20. Sometimes they can have black spots on a red background or red spots on a black background.
- Body shape: Like all ladybugs, Asian ladybugs have a rounded, domed body.
- M’ mark: A distinctive feature of the Asian ladybug is an ‘M’ or ‘W’ mark (depending on how you look at it) on the pronotum, the part of the body just behind the head.
- Behaviour: Unlike many other ladybug species, Asian ladybugs tend to enter homes and other human structures during the fall to hibernate, which can help identify them.
If you are unsure of the identification, you can always consult an entomologist or other insect expert for confirmation.
Where do ladybugs nest?
Ladybugs don’t really make “nests” per se. However, they choose specific places to lay their eggs and to take shelter. Here are some details:
- Egg Laying: Ladybugs lay their eggs in areas where food is abundant, primarily where there is a high aphid population. They often lay their eggs in groups on the underside of the leaves to protect them from predators and the weather.
- Hibernation: During the winter, ladybugs seek shelter from the cold. They can often be found in groups in crevices, under tree bark, in wall cavities or inside houses. This is why clusters of ladybugs are sometimes seen in some parts of buildings during the colder months.
- General Habitat: Ladybugs prefer environments with an abundance of plants as they feed primarily on aphids and other small insects. They can be found in gardens, fields, forests and other vegetated areas.
It is important to note that these behaviours may vary slightly depending on the ladybug species.
|Latin name||Harmonia axyridis|
|Length||4.8 to 7.5 mm|
|Color||red with black dots|
|Life||about 1 year|
MORE INFORMATION ON LADYBUGS
LIFE CYCLE OF LADYBUGS
Like other beetles, the Asian lady beetle is a fully metamorphosing insect, or holometabolus. In spring, the adults come out of their winter shelter to mate. The eggs are attached in small clusters on the underside of the leaves. A clutch has between 6 and 62 eggs measuring 1.3 mm long and 0.5 mm in diameter, whose hue varies from yellow to orange. The eggs are often laid near a colony of aphids, which will serve as food for the young. Each female produces hundreds or even thousands of eggs, making this species more fertile than other ladybugs. The hatching takes place three to five days after the laying. The larva looks like a tiny crocodile, first light gray then black spotted with yellow, orange or red, adorned with spines and tubers. The larva molts three times in about two weeks. Arrived at maturity, it reaches 1 cm in length. It attaches itself under a leaf with the help of a false foot located at the end of its abdomen and transforms itself into an immobile nymph. The final molt, which gives birth to the adult, occurs about a week later. The adult insect is initially pale yellow. It is necessary to wait a few hours to see appearing the final color of its elytra. Under the right conditions, this ladybug takes 36 days or more to grow from egg to adult. There are probably two generations per year in Quebec, perhaps three in years with long, hot summers. In October, the adults gather and then seek shelter for the winter. They can then enter houses, garages, barns and any other building that will protect them from the cold. The adult Asian lady beetle can live up to two or three years.
HABITAT OF LADYBUGS
This mainly arboreal insect establishes itself in several ecosystems. It settles in gardens, fields and crops. The Asian lady beetle can be found on both deciduous and coniferous trees. It prefers to feed on trees and shrubs rather than on low plants. It can be seen on the following plants, among others: pine, fir, apple, peach, pecan, magnolia, maple, oak, rose, alfalfa, tobacco, and cotton. This non-native species is poorly adapted to the harsh Quebec climate. It must therefore spend the winter in a shelter (which sometimes means in our homes) to survive. In Asia, where it originates, it hibernates in caves, cliffs or mountains.
The Asian lady beetle is a predatory species that feeds on a wide variety of small insects. It is particularly fond of aphids, of which it eats about fifty different species. A single ladybug can eat up to 500 aphids per day. Mealybugs, psocoptera, psyllids and spider mites are also on the menu for this species. The larva feeds on aphids, as well as nectar and pollen.
Even so-called beneficial insects can be a nuisance when they are present in large numbers inside our homes. The best way to avoid this type of inconvenience is to prevent it by keeping insects out of your home. To do this, seal openings and cracks, especially around doors and windows, as well as on foundations and siding. Cover air vents with screens. Avoid leaving doors and windows open in the fall or keep your screens up until November. Repair any tears that form.
If ladybugs are already in the house, collect them with a vacuum cleaner. Use this device in preference to a broom to avoid crushing insects. When disturbed, they emit a liquid that smells bad and can stain walls, carpets, fabrics, wallpaper and other materials. Empty the vacuum bag quickly to prevent the formation of stubborn odours. These ladybugs can be useful and do not need to be killed. You can put them back outside where they will find shelter (under a porch or near a woodpile, for example) or keep them in a cool place in the garage or shed to release them in the spring. They can then make themselves useful by eating the aphids in your garden.
The use of insecticides to eliminate ladybugs in the home is not recommended. The corpses remain in small crevices, rotting and can attract other insects, such as beetles.
Most experts believe that exotic ladybug populations often reach excessive levels soon after establishment. However, they eventually return to a normal balance when their preferred prey becomes scarce and predators and parasites that prey on them multiply by taking advantage of their abundance.
Ready to get rid of invasive ladybugs? Contact our experts today!