Long-horned beetle (family Cerambycidae), commonly known as longicorn, is any of the approximately 25,000 species of beetles (insect order Coleoptera) whose common name comes from their extraordinarily long antennae. These beetles can be found all throughout the world, but they are most common in the tropics. They are available in sizes ranging from 2 to 152 mm (less than 1/8 inch to about 6 inches). When the antennae are added, these lengths may double or triple.
Many adults (such as the European Clytus arietes) visit flowers and have wasp-like yellow, black, and orange coloring patterns. Clytus mimics ants in several tropical species. The African Pterognatha gigas looks like a patch of moss or lichen with a few strands jutting out, which are its antennae.
Because the front section of the plump larva is stretched to give it a rounded look, the yellowish or white larvae are commonly referred to as roundheaded borers. The larva bores through and feeds on woody plants for one to two years or more, using its powerful jaws. When the larva is ready to pupate, it bores a tunnel to the outside, pupates within the tree, and emerges as a new adult through this tunnel. Long-horned beetles can be major pests of timber and pulpwood trees, landscape trees, fruit trees, and woody ornamental plants due to their wood-boring behavior.
There are multiple subfamilies within the long-horned beetle family, including the following:
The elytra (wing covers) of prionids (subfamily Prioninae) are leathery and reddish, and the prothorax (area behind the head) borders are toothlike and extended laterally. The pine-dwelling genus Parandra and the broad-necked prionus (Prionus laticollis), whose larvae reside in grape, apple, poplar, blueberry, and other fruit and ornamental tree roots, are both members of this group.
The ribbed pine borer (Rhagium inquisitor) belongs to the cerambycids (subfamily Cerambycinae), which has a small thorax with a spine on each side and three lengthwise ridges on its wing covers. During the larval stage, it lives in pine trees. The locust borer (Megacyllene robiniae), a black cerambycid with yellow stripes across its body, is another cerambycid. Black locust trees are where female locust borers lay their eggs. After the larvae hatch, they burrow into the tree’s inner bark, forming tunnels and exposing the tree to a fungus known as Fomes rimosus, which can cause serious damage (Phellinus rimosus).
The elderberry longhorn (Desmocerus palliatus), sometimes known as the hooded knotty-horn beetle because of its yellow cloak around its shoulders and knotted antennae, belongs to the lepturids (subfamily Lepturinae). It feeds on the elderberry bush’s leaves and blooms, and its larvae dig into the pithy stems.
The sawyer (Monochamus), a gray-brown beetle about 30 mm (1.2 inches) long, not including the long antennae, belongs to the Lamiids (subfamily Lamiinae). The larvae reside in pine and fir trees, bore tunnels up to 10 mm (0.3 inch) in diameter, and feed on the sap. A major apple pest is the roundheaded apple tree borer (Saperda candida). The twig girdler (Oncideres cingulata) lays eggs in twigs before girdling (cutting) a groove around it. The twig eventually dies and falls off, allowing the larvae to develop inside. The Asian long-horned beetle (Anoplophora glabripennis) is a major pest of many hardwood trees, particularly maple, boxelder, horsechestnut, buckeye, willow, and elm. It is endemic to China and Korea. Adults are huge, ranging in size from 1.9 to 3.8 cm (0.75 to 1.5 inches) in length and have irregular white markings on their bodies. Their antennae are black with white rings and range in length from 3.8 to 10.2 cm (1.5 to 4 inches). Adult females eat through the bark and deposit an egg during the summer months, causing a visible dark wound in the tree that is roughly 1.3 cm (0.5 inch) in diameter. After hatching, the larvae move to the tree’s heart, where they feed and mature before burrowing to the outside, leaving a 9.5 mm (0.375 inch) broad hole. The Asian long-horned beetle is assumed to have arrived in North America via wood pallets, causing infestations in New York in 1996 and New Jersey, Chicago, Illinois, and Toronto, Ontario several years later. The Asian long-horned beetle is restricted to isolated areas by measures such as tree removal and destruction, quarantine of infested areas, severe rules on the transport of wood, and insecticide treatments.