Popular shows such as So You Think You Can Dance and Dancing with the Stars have illustrated that there is an extremely wide range of dancing styles. From samba to ballet, and hip hop to tap, there are many forms of dancing in which humans engage. Similarly, honeybees have multiple forms of dancing that they use throughout their lives. Last week we discussed the waggle dance, however this week’s focus will be the shaking dance. Robert Gahl describes the shaking dance as a dorsal-ventral abdominal vibration of the honeybee by means of rapid contractions of leg muscles and pivoting of the legs (Gahl, 230). This dance, enacted by worker bees, can be performed alone, on top one other bee, or atop several bees. A previous study done by Allen, M. indicated that, for dances atop other honeybees, there is no age relationship between the shaker (intiator of the shaking dance) and the bee shaken. In other words, the individual shakers did not tend to shake a particular age-range of worker bees. Contrastingly, Gahl found just the opposite.
Gahl’s study was performed on a small observation hive in which 820 bees were color-marked and uniquely numbered to provide an accurate indication of age. Data collected included the shaking situation (if the bee performed the shaking dance alone, on one other bee, or on several other bees), the age of the shaker, and the age of the bee shaken (if the shaking dance was performed on other/s). Over his 28-day observation, 4949 shaking dances were peformed: 2039 shaking dances were performed alone (41.2%), 2220 were performed on one other bee (44.8%), and 690 were performed straddling more than one bee (14%) (Gahl, 231). Gahl focused on the shaking dances performed one-on-one. (Why he did not look at the other two categories in further detail, I am unsure of.) In regards to correlationship with age, the results were as followed:
The included graph shows the age difference between the shaker and the recipient. A positive number indicates that the shaker was older than the recipient while a negative number indicates that the shaker was younger than the recipient. As you can see, the age difference between the two bees ranged from -9 days and 22 days, with less than 4% of the shaking dances performed on bees older than the shaker. The bees would shake other bees up to 22 days younger than them, however they would not shake any bee older than 9 days.
From this graph, we see that the ages of shakers ranged from 0 to 24 days and the ages of receivers ranged from 0 to 26 days. The majority of shakers were between 9 and 19 days old, while most of the bees that were being shaken were 2 days old. Thus, Gahl’s research shows that “a relationship has been found between the age of the shaker and the bee shaken, the shaker being nearly always older” (Gahl, 232). According to Gahl, shaking is not performed randomly, but with some discrimination determined by age. Some sort of age recognition is taking place within the hive and among the bees. My question is, why have this age recognition? What purpose does it serve? Gahl did not provide any explanations on this other than his results may relate to the function of the shaking dance. In other words, because this shaking dance seems to be driven by certain age-related rules, the purpose of the shaking dance may have something to do with such age discriminations. Is it to train younger, less experienced bees for something? Is it a type of information sharing? Is it a way of exhibiting dominance and therefore establish a type of hierarchy among the bees in the hive? In addition, how do the shakers do this type of age-discrimination? Gahl proposes that the shakers know based on the physiological variation of bees differing in age, traits such as “strength, health, glandular growth, or labour category (which is partially related to age and partially to food conditions in the hive), or some combination of these” (Gahl 232). I wonder if age could also be discriminated by pheromones or other nonvisual cues such as the way the buzz or the pitch at which they buzz.
However, the interesting thing about this article lies in the fact that there is a type of age-discrimination going on, regardless of how this is accomplished or its purpose. This illustrates the intricacies of communication. It is not a simple process that can be generalized over one species. Many things come into play, such as the absolute age of the communicators, and even their ages relative to each other. This is also seen in humans as well. We communicate with people differently based on our ages. There are certain rules to follow when speaking to an elder, and there are particular ways in which we speak to those younger than us. Although much of these rules are socially contrived, communication in itself is a social process.
Gahl, R. A. (1975) The shaking dance of honey bee workers: evidence for age discrimination. Animal Behavior, 23(1), 230-232.
On second thought, could this be just a correlation? Maybe the shaking dance is not discriminatory via age. Instead, it may be something completely separate that is correlated to age. Just a thought.