Description

The ivory-marked beetle is a medium sized member of the beetle family Cerambycidae (longhorned beetles). Adults are brown or tan in coloration, with long, parallel-sided bodies that range from 20 mm to 25 mm in length, excluding the antennae. The antennae are longer than the body, with 10 slender segments and a short oval second segment. Legs are long and slender. Each eye is deeply concave behind the antennal insertion. One pair of small, dark dots occur near the middle of the prothorax immediately behind the head. Each wing cover (elytron) possesses two pairs of long, bright white markings (the ivory marks).

Larvae are slender, segmented grubs with three pairs of tiny legs on the thorax, just behind the head. The front part of the body is broader than the tapering abdominal segments. Full grown larvae are about 30 mm in length. Larvae are similar to those of many others in the family Cerambycidae and are rarely observed unless extracted from their woody hosts. Pupae are enclosed in a fibrous cell within the woody host. They resemble contracted, rudimentary versions of the adults, complete with long antennae pressed against the body in a tight whorl.

Adults are unique among the Louisiana longhorned beetle species based on the striking white elytral markings. Coeleburia quadrigeminata is currently the only member of the genus recorded in Louisiana. It is common throughout forests of southeastern and central U.S. A nearly identical species, C. haldemani, may occur in Louisiana, but some doubt exists about its status as a species. At least seven other species are recorded for the U.S. and many additional species occur in the American tropics. The taxonomy of this genus and other members of the genus group (tribe Eburiini) has undergone changes recently, and most members of the genus Coeleburia are still listed under the previous genus name Eburia.

Life Cycle

The life cycle involves four developmental stages, egg, larva, pupa and adult, as in all beetles. Completing this cycle generally requires at least two years, although this may be greatly extended, depending on environmental conditions. Adults emerge during the summer months and are primarily nocturnal. Females deposit their eggs in weakened or damaged areas of the host tree. After hatching, larvae create galleries packed with feces (frass) by tunneling through dry, dense, deciduous wood. Larvae remain within their woody habitats for the duration of their development. Many species of host trees are utilized, including oak, hickory, maple, cherry, ash, elm and others. Stressed, diseased or overmature trees are more likely serve as hosts than young healthy trees.

Ecological Significance and Pest Status

The larval galleries of ivory-marked beetles and longhorned beetles with similar habits rarely pose a significant economic threat due to their preference for stressed or otherwise unhealthy trees. However, larvae of this species can complete development within finished wood products, sometimes after extended larval durations. Adults may emerge many years after the wood has been processed. Instances have been recorded of emergence from various finished wooden items manufactured from improperly cured lumber. Adult emergences and cosmetic damage have been documented in flooring, doorsills, wardrobes, bedsteads and other finished wood products decades after construction. These unusual extended developmental times can lead to export of the species undetected to far flung parts of the world, though establishment is unlikely in these typically isolated cases.

Contact Us: For advice about pest identification or diagnosis, contact the LSU AgCenter Department of Entomology.

P4048
4/27/26
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