Jewel Beetles of the Family Buprestidae

Jewel beetles are often brilliantly colored, and always have some iridescence (usually on their undersides). Members of the family Buprestidae develop in plants, so they're also called metallic wood borers or flat-head borers. The emerald ash borer, a non-native invasive species responsible for killing millions of ash trees in North America, is likely the best-known member of this beetle family.

Description

You can usually identify an adult jewel beetle by its characteristic shape: an elongate body, nearly oval in shape, but tapered at the hind end into a point. They’re hard-bodied and rather flat, with serrate antennae. The wing covers can be ridged or bumpy. Most jewel beetles measure less than 2 centimeters in length, but some can be quite large, reaching up to 10 centimeters. Jewel beetles vary in color from dull black and browns to bright purples and greens, and can have elaborate markings (or almost none at all).

Jewel beetle larvae aren't often observed since they live inside their host plants. They're referred to as flat-head borers because they are typically flattened, especially in the thoracic region. Larvae are legless. Arthur Evans describes them as having a "square nail" look in his guide, Beetles of Eastern North America.

Jewel beetles tend to be active on sunny days, especially in the heat of the afternoon. They're quick to fly when threatened, however, so can be tough to catch.

Classification

Kingdom – Animalia
Phylum – Arthropoda
Class – Insecta
Order – Coleoptera
Family - Buprestidae

Diet

Adult jewel beetles mainly feed on plant foliage or nectar, although some species feed on pollen and can be observed visiting flowers. Jewel beetle larvae feed on the sapwood of trees and shrubs. Some buprestid larvae are leaf miners, and a few are gallmakers.

Life Cycle

Like all beetles, jewel beetles undergo complete metamorphosis, with four life cycle stages: egg, larva, pupa, and adult. Female buprestid adults usually deposit eggs on the host tree, in the crevices of bark. When the larvae hatch, they immediately tunnel into the tree. The larvae bore winding galleries in the wood as they feed and grow, and eventually pupate within the tree. Adults emerge and exit the tree.

Special Behaviors and Defenses

Some jewel beetles can delay their emergence in certain conditions, such as when the host tree is harvested and milled. Jewel beetles sometimes emerge from wood products, such as flooring or furniture, years after the wood was harvested. Several records exist of buprestid beetles emerging 25 or more years after they were believed to have infested the host wood. The longest known record of delayed emergence is of an adult that emerged a full 51 years after the initial infestation occurred.

Range and Distribution

Nearly 15,000 species of jewel beetles live throughout the world, making the family Buprestidae one of the largest beetle groups. Just over 750 species inhabit North America.

Sources

• Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.
• Bugs Rule! An Introduction to the World of Insects, by Whitney Cranshaw and Richard Redak.
• Beetles of Eastern North America, by Arthur V. Evans.
• Family Buprestidae – Metallic Wood-boring Beetles, Bugguide.net.
• Forest Entomology, by William Ciesla.
• Buprestidae: Jewel Beetles, Commonwealth Scientific and Industrial Research Organisation (CSIRO).
• Chapter 12: Longest Life Cycle, University of Florida Book of Insect Records, Yong Zeng, May 8, 1995.