Research Tools & Location

What kind of equipment do I need to record the bees?

I spent quite a bit of time researching equipment and testing it before I went to Hawaii. Wood’s apidector study of bee frequencies was quite helpful , albeit dated. I settled on a highly sensitive electret condenser shot gun microphone attached to a professional digital stereo recorder .

Where do I place the microphone?

Initially, I placed the microphone with a funnel attached underneath the hive against the bottom screen. The recordings were too weak. On the Big Island, the beekeepers gladly opened up their hives for me, took out a frame, placed the microphone directly inside and then closed the hive. I listened to the recording at a distance through headphones. I made separate recordings of the brood hive and the super for 30-45 minutes. Fortunately, the bees collectively decided that they need not waste their time propolizing the benign intruder.

What is the frequency range of a healthy hive?

In the literature reviewed, I found a variety of answers. Wernner writes,

… [T]he characteristic hum of a beehive, is produced by the "ventilating" worker bees: bees that stand anchored on the comb or some other structure in the hive and create currents of air by beating their wings. This sound, varying in intensity, has a basic frequency of 250 cycles per second and often has strong overtones. It is usually much louder than the buzz of a flying bee, undoubtedly because the sound emitted by the ventilating bee is enhanced by the resonant vibration of the structure on which it is standing.

In an abstract on “monitoring of swarming sounds in bee hives” another frequency range is recorded:

Swarming is indicated by an increase in the power spectral density at about 110 Hz[; approaching to swarm the sound augmented in amplitude and frequency to 300 Hz [300-110=190Hz], occasionally a rapid change occurred from 150 Hz to 500 Hz

This suggests that 190HZ was the natural frequency level of the hive prior to swarming. Based on the above reference, a probable frequency range appears to be between 150-190Hz. Wenner ‘s sound recordings for the hive come in at 250Hz. Given the variances possible, a sound range between approximately 150-250Hz seems reasonable. I brought my brood hive recording to Professor Chang at the University of Colorado School of Music for an explanation of the sound. Professor Chang determined that the sound was an “E3 about 165 Hz with a variance that goes down a perfect fourth and up around a half step”.

Science aside, a beekeeper knows the sound of a healthy hive.

Where do I find healthy bees?

For reasons of isolation and abundance and variety of flowering plants, Hawaiian bees are considered to be healthier than most. On the Big Island, the Royal Hawaiian Honeys honey is certified “organic” because its bees and honey are pest and toxin free. Some Hawaiian bees do have bee diseases and as of the end of 2008, mites. At this point, diseases and mites are neither extensive nor are they treated chemically, if at all. The beekeepers I met with (3/09) told me that their hives were clean and healthy. The keepers I worked with sell their honey at the farmer’s market for a living. 

To Read the Full Version of BHB Research Paper with Footnotes Click HERE