Thursday, December 26, 2013
Elderberry Borer Beetle
A couple of years ago I became acquainted with a woman named Annie Ray who did her doctoral work on beetles in this genus. Her project was centered around the pheromones produced by the female of this species and how the male homes in on her scent. As part of the research we had to dig down into the roots of the elderberries and break open the root masses looking for larvae or pupae.
Females of this species will begin "calling" for males as soon as they emerge from their underground pupal cell. Males come from great distances drawn by her scent and mating takes place immediately. We were certain that each adult we found had already been mated because of how rapidly this activity takes place once the females leave their pupal chamber. Females lay their eggs at the base of elderberry bushes, and the larvae will burrow into the roots or stem bases to feed. When they are ready to pupate they will travel to the soft, pithy parts of the branches, often near the roots and form a pupal cell. They emerge in early spring. Timing is everything when you are seeking to find these beetles before emergence. Literally it had to be timed so that we were digging and searching a few days prior to when we thought they would be coming out of their underground chambers. Once the adults are plentiful, your window of opportunity is gone.
These beetles are not known to cause any significant damage to the elderberry bushes. They do not occur in large enough numbers to wreck havoc. As adults they feed on the pollen in spring.Finding these beetles is not always easy, but once you've found one they are sure to leave an impression with their beautiful color and substantial size. Look for elderberries in full bloom in the spring and with any luck you will be awarded with the sight of one of these gorgeous beetles.