Bark beetles (Coleoptera: Scolytinae) use primarily three senses to locate potential host trees and mates: 1. Visual, largely limited to dark silhouettes similar to tree trunks, 2. Olfactory, pheromones and tree compounds are used to locate host material and conspecifics, 3. Acoustic/Vibrational, used mainly for close-range communication within the tree. Here we tested the effects of sound on log colonization by several bark beetle species to determine if sound deters beetle entry into trees.
A choice-test with two ponderosa pine logs was used to test the efficacy of four sound treatments: beetle stress and attractions calls, biotic (Monchamus titilator stridulation) and abiotic (noise between 0-25kHz). One log received the acoustic treatment via transducer and the other remained without sound. Each beetle was placed in a 5cm tube in-between the logs and given 24 hours to make a decision.
Results from the D. frontalis (southern pine beetle) trials show the stress treatment reduced entry into logs by 72 percent compared to the control. While Ips pini showed no behavioral response to acoustic treatments.
The reduction of bark beetle entry into logs using acoustic treatments indicates that sound could be used as a management tool for certain species. Further research is needed to determine the long-term effects of acoustic treatments on the target organism and other non-target organisms in the environment.
Co Author: Richard Hoffstetter, Northern Arizona University