We all know by personal experience how important sleep is. If I don't sleep well, I'm cranky in the morning and tired and unproductive the rest of the day. One of the consequences of prolonged sleep deprivation is the deterioration of the capacity to communicate, in terms of both communicating ideas and understanding what others are trying to communicate to us. In the case of truly social animals such as the honeybee, social function heavily relies on the ability of the individuals to communicate with each other. Honeybee workers, for example, frequently report to their fellow nestmates about the direction and distance of foraging sources and potential nest sites. They do this by performing an interpretive ‘waggle dance’ in which they indicate the distance to the desired location by the duration of the waggle portion of the dance, and the direction to their destination by the angle of the dance with respect to the sun. As sleep is so important for communication in humans, could it be possible that bees also need their nightly rest to accurately communicate with their nestmates? This was the subject of research in a study recently published by Barret A. Klein and his colleagues at the University of Texas.
To deprive bees of their precious sleep, the scientists first devised a contraption that they suitably called the ‘insominator’. The device consisted of columns of magnets that could be slid up and down the hive's frame. Then the researchers glued small disks made out of steel on the back of some of the bees. When the insominator glided over the hive, the magnets attracted the metal disks, jostling the bees and waking them if they had fallen asleep. The following day, after a long sleepless night for both the bees and the operator of the insominator, the bees went out for their daily foraging excursion. On their return, each bee performed its usual dance while Klein and his colleagues videotaped the events. From these videos, the group of researchers was able to study the variability in the duration and the angle of the dances and, therefore, determine the accuracy of the messages that the bees were trying to convey to their fellow workers.
As expected, the variability in the angle of the waggle was higher in the sleep-deprived bees than in bees that had been allowed to sleep through the night. These findings indicate that the bees' ability to accurately convey the direction of the foraging site had decreased after a night of sleep deprivation. On the other hand, the length of the waggle phase of the dance did not change with sleep deprivation; bees could still precisely tell their nestmates how far away the foraging site was. Klein and his colleagues propose that, perhaps, it is not as costly to signal this type of information.
The fact that a sleepless night impairs the bees' ability to accurately communicate the location of a food source to their nestmates has important implications about the evolution of sleep in social animals. Whether the errors in communication between insomniac bees are significant enough to guide bees to the wrong site, or whether fellow bees are able to find the site in spite of imprecise directions will be the subject of future research for Klein and the team. Either way, I'm too old to pull an all nighter... just keep that insominator away from me.
