Plinthocoelium suaveolens plicatum

Distinguished from the nominate subspecies P. s. suaveolens by bronze or cupreous tints and weak transverse rugae on the pronotum (Linsley 1964). The two subspecies intermingle in northeastern Texas. No other North American cerambycid combines this large size with brilliant metallic green coloration and contrasting orange-black leg pattern. Larval galleries in living Sideroxylon roots with characteristic granular frass piles at tree bases provide additional identification evidence.

Associated with xeric limestone glades and dry woodlands where host plant Sideroxylon lanuginosum occurs. Hilltop glades with deeply dissected limestone/dolomite bedrock support the bumelia trees required for larval development. Adults perch on lower trunks of host trees and visit flowers for feeding.

Western United States and northern Mexico: Texas, New Mexico, Arizona. Ranges intergrade with nominate subspecies in northeastern Texas.

Adults active in summer, with peak activity in July and August in Texas. Activity occurs during hottest part of day (2–4 PM). Adults attracted to fermenting baits and host tree flowers.

Adults feed on nectar and possibly other floral resources of Sideroxylon lanuginosum; attracted to fermenting baits. Larvae feed on living root tissue of Sideroxylon lanuginosum.

• Sideroxylon lanuginosum - obligateLarvae bore in roots of living trees; adults visit flowers. Association first noted by Riley (1880). No other cerambycid species is known to bore in roots of living Sideroxylon.

Larvae develop in galleries within roots of living Sideroxylon lanuginosum, maintaining clean galleries with granular frass ejected at tree bases. Larvae are creamy-white, robust cerambycid form. Pupation occurs within root galleries. Adults emerge in summer.

Adults are extremely wary and alert; detect approach through antennae twitching and posture changes, then flee rapidly. Adults fly to flowers on high branches, making observation and collection difficult. When alarmed on tree trunks, adults may crawl upward briefly before flying away.

Specialized herbivore contributing to nutrient cycling through root feeding in living host trees. Provides food source for birds and other predators. Associated with relictual xeric glade ecosystems supporting plants and animals with south-central U.S. affinities.

Subject of entomological interest due to exceptional beauty. Collected using fermenting bait traps. No economic importance as pest; does not infest houses or dead wood piles in problematic numbers.

• Plinthocoelium suaveolens suaveolensEastern subspecies distinguished by lack of bronze/cupreous pronotal tints and stronger pronotal sculpture; occurs from Florida and Georgia west to intergrade zone in northeastern Texas

• Cerambycidae
• Cerambycinae
• Callichromatini
• longhorned beetle
• bumelia borer
• xeric glade
• root borer
• Sideroxylon
• metallic green
• subspecies
• western United States
• Mexico

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• North America’s most beautiful longhorned beetle | Beetles In The Bush