Species Information

Photo Credit: Jon Katz / USFWS

Valley Elderberry Longhorn Beetle

Desmocerus californicus dimorphus

Basic Species Information

STATUS

Threatened. The species is likely to become endangered in the foreseeable future throughout all or a significant portion of its range, but they are not in danger of extinction right now.

DESCRIPTION

People often call this species "VELB" to avoid saying the whole name. Longhorn beetles (family Cerambidae) are characterized by long tube-like bodies with long antennae, often more than ⅔ of the body length. VELB are stout-bodied.

Males range in length from about 2 cm (about ½ to nearly 1 inch), measured from the front of the head to the end of the abdomen, with antennae about as long as their bodies. Females are slightly broader than males and have shorter antennae. Adult males have red-orange elytra (wing covers) with four elongate spots. The red-orange fades to yellow on some museum specimens. Adult females have dark colored elytra.

FOOD SOURCES

Adults eat elderberry leaves and flowers. Larvae eat the inside of elderberry stems.

HABITAT

The species is nearly always found on or close to its host plant, red or blue elderberry (Sambucus species), along rivers and streams.

Females lay their eggs on the bark. Larvae hatch and burrow into the stems.

Stems need to be at least about one inch in diameter. Learn more from Theresa Sinicrope Talley's VELB information pages.

MATING

There are four stages in the animal's life: egg, larva, pupa and adult. Females lay their eggs on the bark. Larvae hatch and burrow into the stems. The larval stage may last 2 years, after which the larvae enter the pupae stage and transform into adults. Adults are active from March to June, feeding and mating.

RANGE

At the time of listing in 1980, the beetle was known from less than 10 locations on the American River, Putah Creek and Merced River. Now it is known to occur from southern Shasta County to Fresno County. There are about 190 records, mostly based on exit holes.

PREDATORS

Birds, lizards, European earwigs and nonnative animals such as the Argentine ant, may eat the early phases of the beetle.

THREATS

Extensive destruction of California's Central Valley riparian forests has occurred during the last 150 years due to agricultural and urban development. According to some estimates, riparian forest in the Central Valley have declined by as much as 89 percent during that time period. The valley elderberry longhorn beetle, though wide-ranging, is in long-term decline due to human activities that have resulted in widespread alteration and fragmentation of riparian habitats, and to a lesser extent, upland habitats, which support the beetle.

The primary threats to survival of the beetle include:

Loss and alteration of habitat by agricultural conversion

Inappropriate grazing

Levee construction, stream and river channelization, removal of riparian vegetation and rip-rapping of shoreline

Nonnative animals such as the Argentine ant, which may eat the early phases of the beetle

Recreational, industrial and urban development

Insecticide and herbicide use in agricultural areas and along road right-of-ways may be factors limiting the beetle's distribution. The age and quality of individual elderberry shrubs/trees and stands as a food plant for beetle may also be a factor in its limited distribution.

WHAT YOU CAN DO

We have specific Conservation Guidelines for the Valley Elderberry Longhorn Beetle (633 KB | PDF). Contact our office for more information.

Remember that many insects are beneficial. These include honey bees, pollinators, lady bugs, silk worms and many more. Don't automatically kill insects.