Image Credit: Diane F. in Newfoundland and Labrador, Canada
The yellow and blue colors on the Elderberry Borer Beetle are striking and unusual, just like the fruit of their host plant.
The colors on the abdomen of this species are uncommon among most beetles. The top part is bright yellow and the lower part is a metallic blue. The blue may range from dark navy to bright royal blue. The head is black. Adults have black antennae that are about as long as their body. They are often found on the flowers and leaves of their host plant and namesake, elderberry. They are most likely to be seen during late spring and summer.
Elderberry Borer Beetles are native to eastern and central North America. Eggs are laid on elderberry bark, branches and leaves. Hatched larvae bore their way into the center of the stems to feed on the plant's juices. They leave behind frass (insect excrement) that resembles wood shavings. As they mature, the larvae continue to bore down to the roots of the plant where they will pupate. It takes approximately two years to develop into an adult.
Scientific Name: Desmocerus palliatus
Other Name(s): Elder Borer Beetle
Size (Adult; Length): 18mm to 27mm (0.70in to 1.05in)
Colors: yellow, blue, black
Descriptors: tri-colored, flying, antennae, metallic blue
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Antennae: Beetles have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).
Thorax: Holds the three pairs of legs as well as vital internal organs.
Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).
Wings: Appendages used for flying and kept under the elytra until needed.
Abdomen: Houses organs related to circulation, reproduction, and excretion.
Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.