Chrysobothris nelsoni

Chrysobothris nelsoni can be distinguished from other Chrysobothris species by its bright metallic green coloration combined with its specific association with Eriogonum alatum in sand dune habitats of southern Utah and northern Arizona. The species occurs sympatrically with other green Chrysobothris such as C. octocola, but differs in habitat preference (active sand dunes versus mesquite woodland) and host plant association. Adults are most reliably identified by their presence on the basal leaf rosettes of E. alatum, a distinctive plant with tall single stems and branching inflorescences. The species is smaller than C. octocola and lacks the contrasting color patterns seen in some other green Chrysobothris species.

Adults are bright metallic green with a compact, oval body form typical of the genus Chrysobothris. The elytra are smooth and highly reflective, with the brilliant green coloration visible even at distance. Body size is moderate for the genus, with females appearing somewhat larger than males. The pronotum is distinctly narrower than the base of the elytra, and the overall body shape is somewhat flattened dorsoventrally.

Active sand dune systems within pinyon-juniper woodland, specifically where Eriogonum alatum (winged buckwheat) grows in sandy substrates. The habitat is characterized by open sand areas with scattered dune vegetation, often at the margins of larger dune systems such as the Coral Pink Sand Dunes. The species does not occur in stabilized sand areas or in the surrounding woodland matrix away from active dunes.

Known from southern Utah (Kane County, type locality near Coral Pink Sand Dunes) and northern Arizona (Coconino County). The distribution appears restricted to the Colorado Plateau region where suitable sand dune habitat and host plant co-occur.

Adults are active primarily in late spring to early summer, with most records from late May through June. Activity appears to decline by late June, possibly due to increasing temperatures and drying conditions. Adults are diurnal and most readily found during morning hours before temperatures rise excessively.

• Eriogonum alatum - larval hostLarvae develop in the taproot and crown of living plants; adults rest on basal leaf rosettes

Larvae are wood-borers that develop within the taproot and crown of living Eriogonum alatum plants. Evidence of larval activity includes galleries in the crown of the plant that can be exposed by splitting the root. Adults emerge from the host plant and are found resting on the basal rosette of leaves, often sitting head-down at the base of the inflorescence stem. The complete life cycle duration is unknown, but the larval stage likely spans multiple years given the perennial nature of the host plant.

Adults are diurnal and relatively sedentary during daylight hours, typically remaining motionless on the basal leaves of their host plant. When disturbed, adults may fly short distances to adjacent host plants. Activity appears to be temperature-dependent, with beetles becoming more difficult to approach and capture as temperatures rise. Adults have been observed to become less active or possibly burrow into sand at the base of plants during the hottest part of the day or as evening approaches. Nocturnal behavior is unknown.

As a specialist herbivore, the larvae of C. nelsoni act as root borers in their host plant Eriogonum alatum, potentially influencing plant fitness and population dynamics in the sand dune ecosystem. The species is part of a broader community of sand dune specialist insects adapted to this dynamic and physiologically stressful environment. Adults may serve as prey for generalist insectivores including birds and predatory insects.

The species is of interest to coleopterists and naturalists due to its restricted distribution, specialized habitat requirements, and striking metallic coloration. It has been the subject of targeted collecting efforts by entomologists visiting the Coral Pink Sand Dunes area. The species is not known to have any economic importance.

• Chrysobothris octocolaAlso bright metallic green, but occurs in mesquite woodland rather than sand dunes, and is associated with Prosopis glandulosa rather than Eriogonum
• Chrysobothris cuprascensMetallic green to coppery coloration, but associated with pinyon pine (Pinus edulis) as host rather than Eriogonum
• Nanularia brunneaAlso associated with Eriogonum species in similar habitats, but smaller, duller brown in color, and typically found on stems rather than basal leaves

• Buprestidae
• metallic wood-boring beetle
• Eriogonum alatum
• sand dune specialist
• Colorado Plateau
• endemic
• root borer

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Chrysididae | Beetles In The Bush
• Eumastacidae | Beetles In The Bush