Dancing in the dark
Raymond Ramirez | Wednesday, October 28, 2015
“Everything takes time. Bees have to move very fast to stay still.”― David Foster Wallace
Work-study was a great way for me to supplement my student income and an opportunity to work closely with memorable faculty and staff at Notre Dame. My first assignment was assisting Dr. Harald Esch. If you are not familiar with the work of Esch, it is my extreme pleasure to introduce him and his work with honey bees.
As a teacher and faculty member, Esch has a great reputation. He is a past recipient of the Shilts/Leonard Teaching Award, given annually to a faculty member of the college of science selected by a committee of former awardees for overall excellence in teaching. The award is named in part for the late Fr. James Shilts, who taught physics and astronomy and left hundreds of students with an appreciation for the (apparent) retrograde motion of Mars.
Most of my work for Esch was not glamorous, and I was never asked to retrieve brains or send kites into electrical storms in attempts to re-animate the dead. Typically I helped to clean animal cages and set up experiments, most of which involved running small animals through a maze or keeping large tanks of fish available for observation. While preparing Mississippi mud turtles for reaction tests, I picked up what I initially thought were leaves sticking on my hands — though these turned out to be leeches, which hastened my decision to switch majors from Biology to English. I just got a “willies” flashback. His experiments “on the wall-seeking behavior of small rodents” still come to mind every time I see occupants of an elevator align themselves along the sides of the traveling cube.
Esch was already something of a science rockstar when I worked for him, based primarily on his follow-up on the research of Karl Von Frisch into the communication of food sources by scout bees to the rest of the hive. Von Frisch had determined that bees communicate through a series of “dances” consisting of circular movements and wiggles and waggles, combined in a way that tell the bees in the hive there is food, in which direction it is and how distant it is. You are probably familiar with Von Frisch’s work as reflected in a series of iconic biology-textbook illustrations showing bees dancing on a well-lit diagram of circles and squiggles.
Von Frisch’s theory of bee communication was not questioned until Esch and some colleagues asked a simple, but now obvious, question: how were the bees able to see the dance inside of the darkened hive? Esch and other researchers learned that bees recognized the dance of the scout bee by hearing and sensing the dance in the dark. Vital information could be communicated through vibrations.
Esch specifically wanted to know how the bees were able to judge distances between the hive and the food source and communicate that in a meaningful way (well, to other bees). Bees have compound eyes, and Esch guessed that they were able to judge distances by the flickering motions caused by vegetation and terrain reflected into their eyes as they flew. This “flicker effect” served as a proxy for knowledge of actual distances: the bees did not communicate “50 feet to the flowers,” but rather “50 flickers to the flowers.” It was the number (and perhaps intensity) of flickers that the dance conveyed. To test this theory, Dr. Esch set up tubes marked with vertical stripes for the bees to fly through, and the bees reported distances based on the width and frequency of the stripes rather than the actual measured distance. Not only had Esch determined how bees relayed data on distance, but he could feed bees misinformation and control their actions. As I recall, Esch is a good man, and I am fairly confident he will not use this knowledge to unleash his bee army on the world.
Esch had more secrets of bee language to pry from these cagey little hoarders and investigated whether dancers produce scents distinct from non-dancing bees. He found that dancers produce four unique hydrocarbon-based chemicals. Reproducible in the lab, these scents were blown into hives and increased foraging behavior. As in their human counterparts, dancing bees produce scents that affect the behavior of their fellow foragers; perhaps in the case of humans, to move as far away from the scent-producing dancers as possible. Researchers also recently demonstrated that bees seek the buzz offered by caffeine-laced nectar, which amps up their dancing — so much that they tend to overestimate the quality of the food source. Social animals have a lot in common.
Esch’s discoveries are still inspiring researchers. A recent paper in Bee Culture Magazine (seriously) titled “Waggle-Dancing Bees Emit Body Odors: New Evidence of an Important Role for Scent in Bee Foraging Communication” reports additional odor cues, citing Esch as one of the leaders in the field. His entire career has been marked by a willingness to recognize the efforts of his predecessors, patiently toil on new ideas and ask questions that challenge orthodoxy; to see through the darkness and ask, what might be?
So consider the bee when you need to simply shut up and dance.
The views expressed in this column are those of the author and not necessarily those of The Observer.