Valley Elderberry Longhorn Beetle is a beautiful species of beetle found only on elderberry trees. Sadly, its numbers are declining, and its population is in danger. We put the spotlight on this beetle in the article below.
If you live around California, there is a good chance you have seen a bright red-green beetle with four spots on its wings.
These insects are one of the defining species of riparian forests, sticking to elderberry trees throughout their lives.
In this article, we will talk to you about this enchanting creature that spends its entire life wedded to only a single tree.
What are Valley Elderberry Longhorn Beetles?
The Valley Elderberry Longhorn beetle is an endemic beetle to the Central Valley of California. It is found in riparian habitats that are abundant in this area.
They get their name from the elderberry plant, which is their main host plant.
This medium size beetle is a federally threatened species in the US. While it is not endangered, its numbers have gone so low that measures are in place to protect its population.
What Do They Look Like?
Valley Elderberry Longhorn beetles are medium-sized with stout bodies and red-green coloration.
Adult beetles grow upto 0.8 inches, the females being bigger than males. The males have antennae as long as their bodies and four red-orange tints on their wing covers, also known as elytra.
Female beetles can measure between three-quarters of an inch to one inch in length, with shorter antennae than males.
The first pair of their wings do not cover the abdomen, and they have darker elytra than the males.
One good way to tell the male and female beetles apart is by noticing their antenna. The males will have longer and thicker antennae.
Where Are They Found?
They live throughout the Central Valley of California. This includes the areas of Shasta County in the north to Madera County in the south.
Some of the main areas where these beetles can be found are:
- The American River Parkway Zone is a stretch of the American River Parkway on the South Bank of the American river. This extends from west of the Jedediah Smith Memorial Bicycle Trail and north to Palm Drive.
- O’Connor Lakes and the Riparian restoration zone is another area with a beetle population. This area is protected as a restoration zone under the U.S. Fish and Wildlife Service.
- The Sacramento zone is an enclosed area on three sides as a protected forest cover area.
What Do They Eat?
The Valley Elderberry Longhorn Bettle got its name from the tree it feeds on. They exclusively eat elderberry shrubs throughout their life.
The larvae of the beetle feed on the pith of the stems. After that, they spend their pupal stage inside the pith and emerge as adults along with the new shrubs.
The adult beetles consume the leaves, flowers, and nectar of the elderberry tree. These trees act as lifetime host trees to these insects, blooming from March through early June.
Like other common beetle species, the Valley Elderberry Longhorn Beetle has four stages of life – egg, larvae, pupa, and adult.
Their total lifespan is around one to two years, and they spend their entire life cycle around elderberry trees.
Female beetles lay eggs on the bark of elderberry trees. Once they hatch, the larvae make their way to the stems and burrow themselves there.
The larval stage can last as long as two years before they form a pupa and emerge as adults.
The adult beetles are active from March to June, feeding, mating, and reproducing their next generation.
Most adult beetles will feed on the leaves and flowers of the plant. Some are also known to feed on nectar from the flowers of elderberry trees.
Why Are They Endangered?
In the course of the last century, there have been an increasing number of reasons why the numbers of these beautiful creatures have dwindled.
Some of the most pressing issues that have caused this are:
- Their loss of habitat due to urban development and increase in agriculture practices
- Destruction of elderberry trees due to the building of highways and leeves
- Droughts and floods as a direct result of climate change
- The growth of a large number of invasive plants that have taken over the elderberry population
- Use of chemical pesticides on elderberry shrubs that often kill the beetles that feed on them
- The presence of a new species of ant called the Argentine ant that has become a predator of elderberry longhorn beetles
All of these reasons have resulted in the beetle being endangered. While there was a proposal to withdraw their name in 2014, it was rejected due to the current situation of the species.
Frequently Asked Questions
What does the Valley elderberry longhorn beetle eat?
Elderberry longhorn beetles feed exclusively on elderberry shrubs.
They feed on the pith of stems as larvae and move on to eating leaves and flowers as they reach the adult stage.
They also like to drink the nectar of the flowers when they bloom during spring.
Are longhorn beetles poisonous?
Elderberry Longhorn beetles are one of the most innocent creatures as far as humans are concerned.
They are not poisonous in any way, and they do not bite or sting. These insects are more harmful to trees that they burrow in and damage from the inside.
What animal eats elderberry?
Some common animals which eat elderberry trees are rodents and game birds.
Squirrels are one of the frequent visitors of elderberry shrubs. Songbirds and small bird species also flock to the trees for the leaves and fruits.
One recent predator of these insects is the Argentine ant. It has been a major cause for concern because it has adapted to hunt these beetles almost exclusively.
Will deer eat elderberry bushes?
There are reports that show a deer will eat elderberry shrubs as their first choice when they can find any.
In regions with a high deer population, they will feed on elderberry leaves, often damaging the tree as a whole.
These beetles make up a very important part of the ecosystem of riparian forests in California.
There are multiple conservation programs that have been undertaken by the U.S government for the protection of Elderberry beetles.
It is crucial at this point to protect the beautiful creatures to maintain the necessary balance of nature.
Thank you for reading!
The unique appearance of the valley elderberry longhorn beetle, and its threatened status has meant that many of our readers have been enquiring to us about sightings of this bug.
Please go through some of their letters below.
Letter 1 – Elderberry Longhorn
Glacier Park Beetle
Location: Glacier Park, Montana
August 31, 2010 12:23 am
We saw this beetle while hiking in East Glacier Park the first week of august 2010. On a leafy bush, as I recall. I’ve searched a bit for similar bugs and it looks a little like a cardinal beetle as mentioned in another post here – but not exactly. Can you help?
This identification began with two close color matches that were incorrect. The coloration of your beetle resembles Stenelytrana emarginata which is pictured on BugGuide and it also resembles the beetles in the genus Tragidion which are also represented on BugGuide. In both cases, the texture on the elytra or wing covers was wrong. Eventually we found a photo on BugGuide of a the species of Elderberry Longhorn, Desmocerus auripennis, that matched your beetle exactly. There seems to be quite a bit of variation exhibited by this species if you compare the various images posted to BugGuide but there is a dearth of information included. We have not been successful in finding out any additional information on your strikingly beautiful Elderberry Longhorn.
Thank you Daniel, I love what’sthatbug, just never had a bug to submit before!!
Well, you held out for a really good one.
Letter 2 – Elderberry Longhorn
Subject: Beetle in Yosemite NP
Location: Near a creek @ about 6000’
August 3, 2012 3:19 pm
I want to determine if this is a native beetle or non-native. The location is southern Yosemite National Park at about 6000’ in a creek canyon.
The closest match I could come up with is Stictoleptura cordigera, but that would mean it is invasive. It doesn’t really look line the Elderberry longhorn beetle to me… color pattern is off.
This is an Elderberry Longhorn and it is a native species. The beetles in the genus Desmocerus are collectively known as Elderberry Longhorns, and the species that truly owns the common name Elderberry Longhorn is Desmocerus palliatus, a species found in eastern North America according to BugGuide. The other two species are west coast species and Desmocerus aureipennis has two subspecies and several color variations. Your pictures are an exact match to this image of Desmocerus aureipennis aureipennis that is posted to BugGuide as well as to this image of the western Elderberry Longhorn from our archives that does not have a black patch on the elytra. It seems according to the images on BugGuide, that the female of the species has the black patches, though that is not stated. We believe this is a rare species. This is a very beautiful beetle and your photographs are a wonderful addition to our archives.
I’m glad to have helped and glad to know more about this amazing beetle!
Could you please credit the pic to Patrick Roe.
Update: August 6, 2012
Hi there Daniel-
I’ve had two conflicting answers asa to the ID on this beetle. I would like to bring this to your attention in case there was some error on bugguide.net. I should mention I am a ranger in Yosemite and after posing the question to our Wildlife department, I received a response stating it was actually a female Elderberry Longhorn Beetle which is endangered. “The black spot on the elytra (wing covers of beetles) identify it as a female Valley Elderberry Longhorn Beetle.” Is their an identifying mark that would help me distinguish between the two species? I want to make sure this photo is not being mis-identified.
We are a bit confused with this email. You did not indicate which two species you got conflicting answers on and where the conflict originated. Here at What’s That Bug?, we do not have any scientific background, so we always defer to real experts. We deduced the information on the wing patches based on the images posted to BugGuide. Where did your quote come from? What species or subspecies is the Valley Elderberry Longhorn Beetle? since none of the species and subspecies on BugGuide have common names except the general Elderberry Longhorn for the entire genus.
Hi there – Sorry about that!
Here is the picture I sent you and is posted on your site currently. 2012/08/03/elderberry-longhorn-2/
The response I got from the same picture via the Wildlife division here in the park is that it was a Valley Elderberry Longhorn. I’m just not sure what to think now. They were surprised to see I found it at 6000′, when the Valley Elderberry Longhorn’s highest known elevation was 3000′ previously. I’m wondering if they misidentified it or if the bugguide.net site is incorrect…. What is the elevation range of Desmocerus aureipennis aureipennis?
Hi Daniel –
After further discussion – Wildlife division here concurs that it is the Desmocerus aureipennis aureipennis. Thanks for helping me figure this out!!
Thanks for the update Patrick. It is nice to know we are all in agreement now. We want to reiterate that this is a positively gorgeous beetle.
Letter 3 – Elderberry Longhorn
Subject: Green and orange beetle
Location: Newville PA, Cumberland County
June 21, 2013 7:24 pm
I spotted this flying around one evening but it wouldn’t land close enough to get a pic. The next evening I saw it sitting in a tree and was able to get a couple pics. Not the best pic the wind was blowing and the there was branches were moving. When it was flying the wings were large and iridescent green.
This is one of our favorite North American beetles, the Elderberry Longhorn, Desmocerus palliatus. According to BugGuide: “Swampy areas and edges of streams with host plant” which is elderberry as the name indicates. We wrote that it is also called the Cloaked Knotty-Horn, but we can’t remember where we read that. Impressions: Cloaked Knotty-Horn Beetle uses the name. P-Base also uses the name. At last, Encyclopedia Britannica also uses and explains the name: “The lepturids (subfamily Lepturinae) include the elderberry longhorn (Desmocerus palliatus), also called the cloaked knotty-horn beetle because it looks as if it has a yellow cloak on its shoulders and has knotted antennae. It feeds on leaves and flowers of the elderberry bush, and its larvae bore into the pithy stems.” We consider the color to be blue, but leaning towards green.
Letter 4 – Bug of the Month May 2016: Elderberry Longhorn from British Columbia
Subject: BC Beetle
April 30, 2016 4:12 pm
This Beetle has been hanging around our backyard the last three days. We live in southwestern, British Columbia, Canada. Cannot find a match anywhere.
Signature: Jason Peckham
This gorgeous Longhorned Borer Beetle is a subspecies of an Elderberry Longhorn that does not have a common name, Desmocerus aureipennis cribripennis. A close relative in the same genus is more typically called an Elderberry Longhorn, but the same common name also applies to the entire genus. The Elderberry Longhorns are not common and they are generally not found far from their host plant, Elderberry, according to Eric Eaton. Because of your submission’s timely arrival at the beginning of the month, and because of your excellent image, we are designating your Elderberry Longhorn as the Bug of the Month for May 2016. The common name Golden Winged Elder Borer is used on Encyclopedia of Life.
Well that just made my day!
Thank-you so much for you time to enlighten me and everyone in my Facebook and Instagram feeds who were drawing blanks.
I have four little girls and I love that exposing them to and coaching an appreciation for the diversity of life, they come running into the house yelling like someone is on fire when they find a new insect.