This looks like a very interesting project!
Parenthetical remark:
Back in the early 2000s I worked for a while on a bee observation project for which acoustics was to be the primary means of detection. Everyone involved “knew” that honeybees and bumblebees made a buzzing sound, so it seemed reasonable to detect the presence
and trajectory of a bee in the field using sound.
However, it quickly became apparent that bee wingbeats are very inefficient sound sources. The wingbeat frequency of a bumblebee is 100-200 Hz, corresponding to a wavelength lambda in air between 1.75 - 3.43 meters. The bumblebee wing is only about 0.015
meters long, so it is less than 1 percent of the wavelength, and thus a simple source model makes the anticipated radiation resistance proportional to (wing_area/lambda)^2, and acoustic pressure at a distance “r” proportional to 1/(lambda*r). These were small
numbers. The relatively tiny wings are inefficient at launching an acoustic wave: most of the acoustic energy is air moving back and forth around the wings as they swirl and beat.* I wasn’t able to detect a useful wingbeat audio signal out in the field if
more than a 30-40 cm from the bee.
In other words, think about how large a loudspeaker area and displacement would be needed to be to produce a significant sound level a few meters away at 100-200 Hz, and compare that to the wing area of the bumble bee.
Presumably the bee has evolved in such a way that its energy expenditure is not “wasted” on making sound, but is instead used for nonlinear aerodynamics.
*Cf., regarding honeybees:
Short-amplitude high-frequency wing strokes determine the aerodynamics of honeybee flight
Douglas L. Altshuler, William B. Dickson, Jason T. Vance, Stephen P. Roberts, Michael H. Dickinson
Proceedings of the National Academy of Sciences Dec 2005, 102 (50) 18213-18218; DOI: 10.1073/pnas.0506590102
https://www.pnas.org/content/102/50/18213
Best wishes for a successful project,
Rob Maher
--
Robert C. (Rob) Maher, Ph.D., P.E.
Professor of Electrical and Computer Engineering
Montana State University-Bozeman
637 Cobleigh Hall, P.O. Box 173780
Bozeman, MT 59717-3780
http://www.montana.edu/rmaher/
Phone: 406 994 7759 Fax: 406 994 5958
Email: rob.maher@xxxxxxxxxxx Amateur Radio: NR7B
Recent book: Principles of Forensic Audio Analysis (Springer, 2018)
From: AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxxxxxxxxx>
On Behalf Of Picinali, Lorenzo
Sent: Monday, June 10, 2019 8:59 AM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Bumblebee Buzz acoustics PhD advert
Importance: High
NOTICE: This email originated from outside of your organization. Do not click links, open attachments, or respond unless you were expecting
this message and know the content is safe.
Dear Colleagues,
please find attached an advert for a PhD on acoustic biomonitoring , sponsored by the Centre for Doctoral Training in Quantitative & Modelling Skills in Ecology & Evolution (www.imperial.ac.uk/qmee-cdt/).
Please feel free to share this with colleagues and students.
Thanks
Lorenzo