Longhorn Beetle

Oncideres rhodosticta

Mesquite Girdler, Oncideres rhodosticta, photo © by Mike Plagens

This is a male of the Mesquite Girdler, Oncideres rhodosticta, as evidenced by the exceptionally long antennae. These long antennae are the 'horns' in the common name. The beetle was at the lights illuminating a tennis court at Rio Rico, Sta, Cruz Co., Arizona. July 2010.

Cerambycidae -- Long-horned Beetle Family

Sponsored Links

Mesquite trees (e.g. Prosopis velutina) are frequently found with dead twigs, mostly 2 to 3 cm in diameter. Each dead twig served as a nursery for a developing Mesquite Girdler that tunneled its length. Adult females chew a groove around a twig cutting off sap flow thus permitting unhindered feeding by the developing grub within.

Eventually the hollowed twigs break off, but until then the twigs become important nesting sites for native pollinator bees and arboreal ants. These subsequent guests are beneficial to the tree. The pruning activities of mesquite girdlers in the wild environment often results in beautiful trees that no gardener could duplicate.

More Information:

Sponsored Links:

Sonoran Desert Field Guide
Sonoran Desert Places
Sonoran Desert Naturalist Home Page


Copyright Michael J. Plagens, page created 26 Aug. 2010,
updated 23 Aug. 2015.