The Good, The Bad, and the Bugly

Kelly’s Field Notes

Common Name: Longhorn Beetles, Longicorn, larvae are often called roundheaded borers

Order: Coleoptera

Family: Cerambycidae

Genus: There are around 4,000 described genera of longhorn beetles (Rossa and Goczal, 2021).

Interesting Species: There are around 35,000 extant (currently living) species of longhorn beetles (Rossa and Goczal, 2021).

• Titan beetle (Titanus giganteus) - found in the Amazon rainforest, this species is one of the largest beetles on Earth! With a body length of up to 17 cm (6.7 in) long. Their jaws are so strong they can snap a pencil (Smithsonian, 2011).

• Rosalia longicorn (Rosalia alpina) - this beautiful blue spotted longhorn beetle is the symbol for several European conservation groups/researchers (Hoskovec, 2025; LIFE Prognosis, 2025). They are listed as Threatened on the IUCN Red List and have become a symbol of forest conservation. They are found throughout European and western Asia.

• Musk beetle (Aromia moschata) - found throughout Europe and Asia, they emit a sweet musky odor from glands on their thorax. This scent is used to attract mates and deter predators (Hoskovec, 2022). Humans generally find the smell to be pleasant, and it is far reaching spreading over a few miles.

• Harlequin beetle (Acrocinus longimanus) - found in Central and South America, some males have forelegs that are so long they are longer than their bodies! They also have pseudoscorpion buddies who hitch rides on their backs (Piper, 2014).

• Red-headed Ash Borer (Neoclytus acuminatus) - a common species in North America with a striking striped coloration that mimics wasps. The larvae feed on hardwood trees and sometimes are brought inside with firewood.

Description: 

Adult longhorns often have very long antennae, typically at least two-thirds the length of their body, and in many species the antennae are actually longer than the body. Their body shape is elongated and somewhat flattened. They have a very wide range of sizes, as some adults are only a few mm in length like the smallest longhorn beetle Cyrtinus pygmaeus at 3mm up to the largest, Titanus giganteus, at 17 cm in length (Macrae, 2013). Longhorn beetle coloration and patterns vary widely, from bright greens and blues to cryptic browns and black. Adults can squeak or chirp through stridulation, by rubbing the back of their head against their thorax. This is used to frighten away predators.

The longhorn larvae (sometimes called "round-headed borers") are typically creamy-white and found within wood, both living and dead. While typically the larvae are not huge, 1–5 cm (0.4–2 in) in length., the largest larvae (again our friend the Titan beetle) are 20–25 cm (8–10 in) in length.

Life Cycle: 

After mating, longhorn beetle females lay individual eggs within wood (living or dead). They might deposit the egg underneath bark, within a pit in the wood, near the roots, or any other crevasse. Sometimes the female beetle will bore into the tree herself. When the eggs hatch (in a few days or weeks depending on species and environment), the larvae remain where they are, consuming wood (Missouri Department of Conservation, 2024). Most of the beetle’s life will be in the larval or grub stage, which can last a few months or up to 3 years depending on species (US Fish & Wildlife Service, 2025). During this part of their life they are performing an important service within their ecosystem by breaking down wood and returning those nutrients to the soil.

The extensive tunnels they bore through the wood are sometimes referred to as “galleries” for their artistic value and others are called “girdlers” as they tunnel just under the bark of limbs, severing (girdling) the limb's vascular system (Missouri Department of Conservation, 2024). 

When the larva has eaten enough to pupate, it will create a chamber within the wood and form a pupae. This stage can last from a few weeks to a few months. When they emerge as adults, the adults chew their way out of the wood leaving oval or round exit holes. Adults can live for a few weeks up to a few months. In their adult form, they feed on twigs, bark, leaf veins, and leaf petioles.

The overall lifespan of a longhorn beetle can range from a few months to decades, but most live 1–3 years (Missouri Department of Conservation, 2024).

The Asian Longhorn Beetles as an Example Invasive Longhorn Species:

The Asian longhorn beetle (Anoplophora glabripennis) is native to China and parts of Korea. The beetle was accidentally introduced to new countries through wood packing materials (pallets, crates, etc.) used in international shipping. It was first detected in the U.S. (1996, New York), then in Canada (2003), and several European countries (including Austria, Germany, Italy, and the U.K.) (Bronsky, 2024). 

The larvae tunnel deep into the wood of hardwood trees (maple, birch, poplar, willow, elm, and horse chestnut) (Bronsky, 2024). Their feeding disrupts the flow of water and nutrients, leading to branch dieback, structural weakness, and eventual tree death. Because larvae live hidden inside the wood, infestations are difficult to detect until significant damage has occurred.

The issues stemming from the loss of these trees is great. In cities, trees are lost to infestation that line streets and shade parks. Infested trees also lose commercial value; quarantines restrict wood movement and disrupt the industries that buy and sell hardwoods. There is also an ecological impact, as the trees dying from these infestations were homes and food sources to many forms of wildlife, including birds, insects, and small mammals. The U.S. alone has spent over $537 million on Asian longhorn beetle eradication measures. When taking into consideration other longhorn beetle pest species, the U.S. has an annual loss of U $1.7 billion due to loss of timber, syrup, city shade trees, etc (Campbell, 2020).

The Asian longhorn beetle is still an issue in the U.S. and in other countries. In the U.S., strict quarantines are imposed around infested areas to prevent spread. Infested trees are cut down and destroyed (usually chipped or burned), due to insecticides being ineffective as the larvae burrow deep within the wood. There are also public reporting programs in place to help detect new outbreaks as early as possible. Several outbreaks in the U.S. and Europe have been declared fully eradicated, but constant vigilance is required. In New Jersey alone over $12 million has been spent on the eradication program (Kuperus, 2006). International standards (ISPM 15) now require heat treatment or fumigation of wooden packaging to prevent further introductions (USDA, 2025). Despite progress, new infestations still occur, demonstrating prevention and monitoring are ongoing challenges.

Super Powers:

• Jaws - able to chew through wood, longhorn beetles have incredibly strong jaws!

• Antennal Radar - with sensitive and ridiculously long antennae, longhorn beetles can sense each other, vibrations, and subtle cues from trees from far distances.

• Drilling - females and larvae can drill through hard wood.

• Flight - have wings, will fly.

• Beautiful - similar to the jewel beetles, many species have iridescent coloration

Longhorn Beetles in Greek Mythology -

The family name of longhorn beetles, Cerambycidae, comes from a Greek myth where the shepherd Cerambus is transformed into a longhorn beetle after he insults a group of mountain nymphs. He was a pretty rude guy and started spreading rumors about them. Word got back to the nymphs so they turned him into a beetle as punishment (Metamorphoses, chapter 22).

References: 

Bronsky, Kathryn. “Asian Longhorned Beetle | Animal and Plant Health Inspection Service.” USDA, 24 July 2024, www.aphis.usda.gov/plant-pests-diseases/alb.

Campbell, Faith. “Asian Longhorned Beetle.” Don’t Move Firewood.org, 2020, www.dontmovefirewood.org/pest_pathogen/asian-long-horned-beetle-html.

Hoskovec , Michal. “Aromia Moschata (Linnaeus, 1758).” Cerambycinae, 2022, www.cerambyx.uochb.cz/aromia_moschata_moschata.php.

Hoskovec, Michal. “Rosalia Alpina Alpina.” Cerambycinae, 2025, www.cerambyx.uochb.cz/rosalia_alpina.php.

Import ISPM 15-Compliant Wood Packaging Material into the United States. USDA, 2025, www.aphis.usda.gov/plant-imports/wood-packaging-material/import.

‌Kuperus, Charles. Rule Proposal Asian Longhorned Beetle. NJ Department of Agriculture, 2006, www.nj.gov/agriculture/rule/rule220852.shtml.

“Longhorned Beetles (Borers; Sawyer Beetles).” Missouri Department of Conservation, 2024, mdc.mo.gov/discover-nature/field-guide/longhorned-beetles-borers-sawyer-beetles.

‌Macrae, Ted. “North America’s Itsiest Bitsiest Longhorned Beetle.” Beetles in the Bush, 2013, beetlesinthebush.com/2013/05/29/north-americas-itsiest-bitsiest-longhorned-beetle/.

Piper, Ross. Wonderful Creatures: Meet the Beetle-Riding Arachnid. Mongabay, 2014, news.mongabay.com/2014/03/wonderful-creatures-meet-the-beetle-riding-arachnid/.

‌Rossa, Robert, and Jakub Goczał. "Global diversity and distribution of longhorn beetles (Coleoptera: Cerambycidae)." The European Zoological Journal 88.1 (2021): 289-302.

“The Story of Our Logo – LIFE Prognoses.” Lifeprognoses.eu, 2025, lifeprognoses.eu/the-story-of-our-logo/. Accessed 23 Oct. 2025.

“Titan Beetle.” Smithsonian Institute, 31 May 2011, www.si.edu/collections/snapshot/titan-beetle. Accessed 23 Oct. 2025.

“Valley Elderberry Longhorn Beetle (Desmocerus Californicus Dimorphus) | U.S. Fish & Wildlife Service.” FWS.gov, 2025, www.fws.gov/species/valley-elderberry-longhorn-beetle-desmocerus-californicus-dimorphus.