March 17, 2017

Bees Aren't Just Busy... They're Smart

Bees are known for being industrious and having complex social structures within their communities, but perhaps they will also become well known for their problem-solving skills and cognitive abilities.
By Karen Todd-Jenkins, VMD
In an article published last month in Science, investigators at Queen Mary University of London reported that bees demonstrate cognitive flexibility, or the ability to adapt their thinking to address unexpected environmental conditions.
 
Study Design
The basic study design required bees to move a small, yellow ball from one location to another location in order to receive a food reward in the form of a sugar solution.  
 
To begin the study, bees were shown a small, yellow ball in the center of a blue, circular platform. Once the bee found the ball, a small hole in the center of the ball allowed the bee to access a sugar solution as a reward. The bees were exposed to this setup for approximately 2 days.
 
For the next part of the experiment, the ball was moved to the edge of the platform. Upon reaching the ball, the bees had to move it to the center of the platform in order to access the sugar solution. The bees were given 5 minutes to perform the task.
 
Bees unable to perform the task received assistance from the investigators in the form of a demonstration using a plastic bee attached to a transparent stick. When the live bee was on the platform and close to the ball, the fake bee was used to move the ball and guide the live bee to the correct location. The live bee was then allowed to access the sugar solution. Bees that couldn’t complete the test at least 60% of the time were removed from further phases of the study. This segment of the study was referred to by the investigators as pre-training.
 
For the next part of the study (the trial segment), 14 bees from 3 colonies were assessed using a similar test on a larger platform, but no assistance or demonstrations were offered. The bees were tested 10 times. Parameters assessed included how quickly they completed the task, how often they did it successfully, and how far they moved the ball in order to complete the test.
 
Social learning (ie, learning by observing others and subsequently modifying one’s behavior) was also evaluated in the study. For this assessment, bees were pre-trained using a square platform but generally followed the same pre-training protocol used before. The trial phase for this part of the study used 3 yellow balls positioned at various distances from the center of the platform. The ball farthest from the platform’s center was mobile, but the 2 balls closest to the center were glued down so they couldn’t be moved. The trial tested three scenarios, each of which used 10 bees:
  1. Bees that had been previously trained earned a reward if they could move the ball that was farthest from the center of the platform to the correct location. Other bees were allowed to witness live bees completing this test.
  2. Bees were permitted to witness a “ghost” demonstration, in which a magnet hidden under the platform was used to move the most distant ball to the center of the platform, where the sugar water reward was offered.
  3. No demonstration was offered, but bees found the ball already at the center of the platform and received a reward.
 
After pre-training, bees were required to move any 1 of the 3 balls to the center of the platform to receive the sugar solution. Investigators also altered the color of 1 of the balls to see if the bees would use a black ball as readily as they’d used a yellow one.
 
Results and Discussion
Of the 14 bees initially selected and pre-trained for the first segment of the trial, 9 completed the testing and were included in the statistical evaluation. Thirty bees completed the social learning segment of the study.
 
During the study, the bees became faster the more times they repeated the task. They also traveled shorter distances with the ball to reach the goal of the food reward. During the phase of the study that examined social learning, bees that observed a live demonstration completed the task more often and more quickly than bees that received the “ghost demonstration” or no demonstration at all. Further, bees that witnessed the ghost demonstration did better than those that received no demonstration.
 
Investigators concluded that witnessing the ball moving helped the bees complete the test. Similarly, watching other bees successfully compete the test helped the bees perform better and more quickly.

The bees also consistently manipulated the ball that was most distant from the center because they’d “learned” that the other 2 balls didn’t move. Changing the color of the ball didn’t seem to inhibit the bees’ ability to recognize the test and complete the task.


 
The scientists suggested that this study design represented a true test of bee intelligence because the bees weren’t subjected to situations they might encounter during daily life, such as during foraging. For example, the bees realized that they had to walk backwards to roll (ie, pull) the ball; this is not a natural activity they would perform in the wild, so it can’t simply be attributed to evolutionary adaptation.
 
Additionally, the bees that observed and followed demonstrations did so while moving forward. But when it was their turn to move the ball, they did so backwards. This indicates that they didn’t simply imitate what they saw but learned how to adapt (ie, walking backward) to reach the goal and earn a reward. The authors note, “We present an example in which an insect displays a goal-directed behavior for which evolution has not provided them with a rigid adaptation.”   
 
The study may offer insight into how bees solve problems. The authors further suggest that these cognitive skills could allow bees to adapt to new food sources if environmental pressures make such changes necessary. 
 
Dr. Todd-Jenkins received her VMD degree from the University of Pennsylvania School of Veterinary Medicine. She is a medical writer and has remained in clinical practice for over 20 years. She is a member of the American Medical Writers Association and One Health Initiative.

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