Asian Longhorn Beetle

The Asian longhorn beetle is one of the most invasive beetle species in the world. They have several common names, including sky beetle or starry sky. These names are derived from the white spots found on their reflective black shells, resembling stars in the night sky.

People dread seeing Asian longhorn beetles because of their reputation for destroying urban trees and forests. These beetles might be small, but the damage they cause can cost foresters millions of dollars in revenue.

These beetles are native to Asian countries like China and Korea, as their name suggests. However, they were brought over to North America and Europe through infested wood.

Asian Longhorn Beetle Species, Types, and Scientific Name

Asian longhorn beetles belong to the genus Anoplophora; other members of this genus include:

• Citrus longhorn beetle
• Anoplophora elegans
• Anoplophora graafi
• Anoplophora huangjianbini

Their scientific name is Anoplophora glabripennis, and they are members of the order Coleoptera. This order consists of weevils and beetles and is the biggest order of Insecta as there are over 360,000 species. Many of which have bright metallic coloring.

They are easily identified by their two sets of wings, one pair in the front, called elytra, and one pair in the rear. The elytra generally cover the other set of wings and most of the abdomen.

These beetles belong to the Family Cerambycidae and are best recognized by their elongated bodies and compounded eyes. Their bodies are separated into five segments; however, their fourth segment is tiny and well-hidden.

Members of this family are usually seen feeding on flowers; however, they are nocturnal creatures, so sightings are rare. Their larvae are legless, white, and destroy wood.

Appearance: How To Identify the Asian Longhorn Beetle

Adult Asian longhorn beetles are easily identifiable due to their striking features. They have shiny, hard exoskeletons that are black in color, with 20 white spots on their wings.

However, their most distinctive feature is their antennae, which are 1.5 to 2 times the size of their bodies. And upon closer inspection, you can see that the antennae are covered in black and white bands.

In addition, the top part of their legs is a blueish-white color. While their characteristics are quite unique, they are still often confused with the white-spotted sawyer beetle.

Asian longhorn beetles are 0.7 to 1.5 inches in length; however, their antennae can grow twice the size of their bodies. Therefore, when compared to soldier beetles, they are twice the size.

Habitat: Where to Find the Asian Longhorn Beetle

Asian longhorn beetles prefer to live in hardwood hosts. They originate from Asian countries like China and Japan but soon made their way over to North America and Europe by packing wood from an infested tree.

It is very hard to get rid of these beetles, and usually, the bark and branches of infested trees will need to be removed and quarantined with regular follow-up inspections. Unfortunately, this means they can easily spread to various locations without any significant threat.

They thrive in hardwoods like:

• Maple trees
• Elm trees
• Willow trees
• Poplar trees
• Birch trees
• Katsura trees
• Ash trees
• Beech trees

However, they have shown a preference for maple trees as their host. Signs of infestation are exit holes in the wood around 3/8 of an inch wide. Adults are diurnal and extremely territorial, often fighting with members of the same species.

Diet: What Do Asian Longhorn Beetles Eat?

These beetles are herbivores and primarily feed on:

• Trees
• Bark
• Other plant matter

Life Cycle of the Asian Longhorn Beetle

The life cycle of Asian longhorn beetles differs depending on their geographic location. However, an average life cycle ranges from 1 to 4 years.

Their mating season occurs between May and October when the adults will feed and mate on the crowns of trees. Then, the females will lay their eggs in crevices in the wood, where they will chew on the bark.

The eggs are laid in the warmer months and take 2 to 3 weeks to hatch. After that, larvae go through 7 to 8 growth stages before they turn into pupae, which generally happens in spring.

Their entire life cycle from larvae to beetle usually takes around 2 years in Asia. However, it may take longer in areas where they are an invasive species, like the UK and USA. It is not uncommon for their life cycle to take 3 to 4 years in colder regions. Once the beetles emerge, they search for mates, lay eggs, and die.

Asian Longhorn Predators

Asian longhorn beetles have many predators, which include:

• Spiders
• Click beetles
• Flat bark beetles
• Clerid beetles
• Ambush bugs
• Thrips
• Assassin bugs
• Carpenter ants
• Certain species of wasps

Prevention: How to Get Rid of the Asian Longhorn Beetle

In North America and Europe, two of the most invasive species that are destroying urban trees and forests are the Anoplophora glabripennis (Asian longhorn beetle), and Anoplophora chinesis (black and white citrus longhorn beetle)

Because they are so detrimental, significant efforts have been made to prevent and eradicate this species from both continents.

Countries have combined their knowledge of eradication methods, which have proven worthwhile as some areas have seen a 45 % decrease in populations of longhorn beetles in the last 12 years.

In fact, some countries have managed to completely eradicate the species. While it can be costly to remove these pests, the benefits far outweigh the cons.

Interestingly, attempts to rid trees of the black and white citrus longhorn beetle are more challenging than the Asian longhorn beetle. But, the biggest hurdle to overcome is the arrival of new beetles from Asia and other infested regions.

The same eradication methods have been used for decades, and host removal is the most common for this species. However, as life evolves, so do the detection methods, and semiochemical research might be the answer everyone is looking for. In addition, detection dogs have also proved effective.

Up Next

• Dung beetle facts
• Types of beetles
• Common furniture beetle

1. Forest Research, Available here: https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/asian-longhorn-beetle-anoplophora-glabripennis/
2. Kidadl, Available here: https://kidadl.com/facts/animals/asian-longhorned-beetle-facts
3. Wikipedia, Available here: https://en.wikipedia.org/wiki/Asian_long-horned_beetle#Range,_habitat,_and_hosts