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1 de Ridder 1 Title: A Life Lesson, A Tiny Teacher: Honeybee Politics Author: Kendal de Ridder Abstract This paper aims to examine the intricate communication methods of honeybees; beginning with the initial scouting for a new home, to the democratic group decision on said home, and finally, the organized movement of the hive. Introduction The importance of honeybees in our ecosystem is incontestable. These tiny organisms are the primary pollinator for more than 50 fruit and vegetable crops, which form the nutritional basis of our daily diets. Not only do honeybees provide us with this crucial link between pollen and food, but also act as an example of a community working together towards a unified goal: the group s safety and longevity. One common misconception about the inner workings of a bee community is the belief that a hive s members slave away at the mercy of a dictator, the queen bee. In actuality, each hive is composed of a few thousand individuals with distinct tasks, all ensuring the survival and reproduction of their queen, and essentially their species. Few think to look to honeybees when debating politics; however, in 1944, Professor Karl von Frisch began such a study that would continue long after he was gone. Von Frisch s patient observations led to the discovery of a complex method of communication, the waggle dance, between worker bees and the rest of the hive. A young graduate student of von Frisch, Martin Lindauer, had a similar knack for minute observation. Lindauer, while observing the dancers, gradually realized that particular bees did not return covered in pollen, but rather covered in dirt particles. Lindauer hypothesized that these bees were nest-siting scouts and with a series of relatively simple experiments, concluded that the locations and direction indicated by the dancers

2 de Ridder 2 led to the location of the hive s next home. This paper aims to examine the intricate communication methods of honeybees during their collective movement to a new home; beginning with the initial scouting, to the democratic group decision on said home, and finally, the organized movement of the hive. Discussion: Social insect colonies are often founded by a queen. The queen will initiated a nest and rear workers to take over the non-reproductive tasks such as house-keeping, foraging, or protecting the hive. However, occasionally, a colony will rear a queen. As an existing colony grows, the hive may become too small for the entire colony to continue to live as one. A colony will split into two groups and one group will eventually set out searching for a new home. This behavior is known as colony fission (Visscher 2007). This is one of the main reasons a honeybee swarm will begin its search for a new nest site. The other reason for relocation is known as colony emigration. A colony will relocate to a new nest if the nest is unsuitable for any reason. Often anthropogenic damage or a catastrophic event can ruin an existing home and force a hive to move (Visscher 2007). A change in resource availability in the surrounding area can also cause such a migration. Whatever the reason may be, a colony will choose a new nest site in a very systematic, all-inclusive, way which will result in the best possible location to ensure the hive s safety and prosperity. Honeybee swarms act as a super organism when choosing a new nest site. Individual scouts will convey a preferred site to the hive by performing a waggle dance. The more waggle dance circuits that the bee performs, the better the site. The dancers will indicate the direction and distance of the potential home with the angle and duration of their dance. A swarm of bees is capable of choosing a nest site when multiple sites are

3 de Ridder 3 available. However, an individual is unable to actually make a comparative decision between sites. Seeley and colleges investigated the group decision-making process in swarms. The team hypothesized that the dancing scouts would come to a consensus on one site when a sufficient number of scouts were dancing for a single site and then move to the new location (Seeley et. al. 2006). The team set up two identical potential nesting sites and placed the swarm in the center of an island. The swarm often moved to one of the identical sites even when they had not come to an all-inclusive consensus (Seeley et. al. 2006). To account for this dilemma in their original hypothesis, the team postulated that scouts may dance for a site at the site itself rather than returning to the previous home. In a second experiment, the team attempted to delay the hive s decision on a new home. The delay in the decision-making process correlated to a delay in the swarms move. The researchers concluded that hives have two main methods to choose the best option when alternative options present themselves. Firstly, bees at a great site will increase and secondly, bees at a sufficient site will decrease. Individual scouts will return to a site multiple times, promoting others to make the trip, if the site provides terrific protection. An individual scout will compete with the other scouts to promote its site. Each scout has equal opportunity to promote a site, however, a decision is not made until the majority rules. In this way, the group, as a super-organism, makes a comparative decision resulting in the best possible option for the hive (Seeley et. al. 2006). A swarm of bees is capable of choosing a nest site when multiple alternative sites are available, however, they are not capable of make a comparative decision. This discrepancy between their realistic cognitive capability and their actions has led to several studies investigating the steps of moving to a new nest-site. Moving to a new home is not a trivial

4 de Ridder 4 decision; the change in location can be detrimental to the entire hive if resource availability is low in the surrounding area or if the site is exposed to any danger. This crucial choice is a fascinating example of social insects ability to make a group-decision, due to the fact that all party members involved must agree on a single location and each individual is able to give positive or negative feedback on the issue at hand. This is not always the case. In some situations, the best tactic may be to keep multiple options open. For example, honeybee foragers often use strategic bet hedging when searching for food. Bet hedging is defined as a strategy that reduces the temporal variance in fitness at the expense of a lowered arithmetic mean fitness (Jorgen, et. al. 2009). In other words, it is wise to refrain from putting all of your eggs in one basket. Bet hedging is a wise tactic when considering foraging sites due to the vulnerability of each location and the limited resources available. By maintaining knowledge of and contact with several locations, honeybees decrease the likelihood of running out of food (Seeley 1995). When a honeybee swarm chooses its future home, it practices a form of politics known as direct democracy (Seeley 2010). Direct democracy is a group decision-making method in which the individuals within a community choose to participate in a debate personally rather than through representation. The final decision therefore rests in the hands of several hundred individuals, rather than a sovereign, the queen bee. As scouts begin to present their proposed option of a new home, the group selects its course of action by competing against one another for the alliance of the other hive members. Each individual assesses an option and then provides feedback on the proposal via a waggle dance. In this way, hives are able to simultaneously process widely scattered information.

5 de Ridder 5 Not all honeybees are scouting for a new home. The division of labor amongst a hive is typically determined by age and pheromones within the hive that cue an individual to switch a caste depending on the needs of the hive at a given time. The responsibility of a honeybee within a hive is a constantly shifting, labor-intensive paradigm. The hive adapts a push-pull division of labor. In other words, individuals will adapt to the needs of the entire colony in order to ensure all tasks are being performed and one caste is not overly represented within the entire colony (Johnson and Frost 2012). As a honeybee progresses in its short lifetime (2-3 weeks), its role changes according to its development and experience level. From birth to about 3 days of age, a honeybee s role is to strengthen its wings and clean cells within the hive. By about 5-8 days of age, a bee advances to a nursing position (which entails feeding and caring for larvae), and eventually (9-10 days) the bees are strong enough and intelligent enough to become foragers. Not all bees in the hive will perform each task as they age. Environmental pressures as well as the genomic makeup of an individual may persuade said individual in a predetermined inclination towards a specific caste (Johnson and Frost 2012). In fact, studies monitoring the roles of individual bees have shown that some bees will make the natural progressive shift to the next caste and then revert back to their previous position. Generally, the middle aged behavioral states seem to have the most fluidity (Johnson and Frost 2012). Brian Johnson and Elizabeth Frost discovered that primer pheromones (chemical scents) control and regulate the switching between castes within the hive. In particular regions in a bee s nest, specific chemical cues will inspire a bee to switch to a particular caste. These cues, as well as the demand of the hive as one entity, are the driving force of a bee s working life (Johnson and Frost 2012). In the initial proceedings of moving, the queen bee and her workers take off as a collective entity and settle in a tree to begin their democratic decision of a new home. From here,

6 de Ridder 6 a multi-day scouting process begins while the queen and younger members of the hive await the scout s findings. If the scouts find a suitable hole, they express their enthusiasm via dancing. The pattern of their dances indicates the direction and distance of the potential home (Seeley and Buhrman 2001). Dances will entice other scouts to investigate the location and in turn express their thoughts to the rest of the hive via a dance. Studies have looked at the mechanisms by which bees evaluate dances as well as the overall trends seen in dancing behaviors. Although little progress has been made as to the correlation between specific moves and meaning, one such study found that the dances of individuals tend to decrease in strength as the process progresses (Buhrman 2001). A bee s allegiance to a given site will often switch as the positive-feedback loop advances (Visscher and Camazine 1999). This mechanism of feedback negates the necessity for a bee to make a comparative decision. By interacting and evaluating an individual s assessment of a location, the hive as a group compares varying location and no individual is required to make an entire assessment. This informational flow between party members allows for a decision to be made that will optimally benefit the group without exceeding the mental capability of any one member involved. During the process of swarming and scouting, honeybees use several forms of acoustic communication mechanisms. The stop signal and the worker-piping signal, were analyzed by a team of researchers in The stop signal causes scouting bees to stop dancing whereas the worker-piping signal excites and accelerates scouting behaviors (Schlegel, et. al. 2012). The bees create the distinct sounds by vibrating their wings against one another s bodies. The two signals differed in their signal duration, fundamental frequency, and frequency modulation (Schlegel, et. al. 2012). By recording these differences at the same time on the same subjects (thereby

7 de Ridder 7 eliminating variables), they found that the noises differ mainly in their mean duration and subtly in their mean frequencies. They hypothesized that the sender bee s location relative to the receiver bee may be another mechanism of behavioral communication due to the negligible differences in the actual acoustics of the two signals (Schlegel, et. al. 2012). Overall, the researchers felt that there may be hidden differences that would require accurate vibration amplitude collection and comparison to detect and discriminate between the two vibrational communication mechanisms which essentially cause opposite behavioral effects (Schlegel, et. al. 2012). When examining stop signaling behaviors within a swarm, Seeley and his team drew a parallel between the decision-making mechanisms found in neurons and the overall regulation of signaling amongst the swarm. Whether it be neurons or individuals within a swarm, a decision is made via analysis of the interaction of the excitable components (Seeley, et. al. 2012). Seeley suggests that the units reach a threshold of activity, which causes a decision to be made. Previous studies of neuron communication have shown that neuronal signals will inhibit conflicting signals to a degree that is comparable to their level of activation (Bogacz, et. al. 2006). Similarly, when looking at two groups of scouts promoting two equally favorable nest-sites, the honeybees will produce stop signals towards scouts advocating the move to the opposite location. The accumulation of stop signals from multiple bees will cause a dancer to stop promoting its given location. This cross-regulation among the scouting bees produces a reliable collective decision amongst the hive for the best future home. Organization of a swarm of thousands of bees to a single predetermined location is not an easy task. As stated previously, the mechanisms used to organize a swarm s move from the parental site to a new home are still relatively uncertain. In 2008, using video recordings of

8 de Ridder 8 swarms, Seeley and Rangel concluded that certain communication mechanisms are enhanced before the exodus from the hive. Specifically, 60 minutes before the move, a communication mechanism known as the piping signal increases exponentially (Rangel and Seeley 2008). The piping signal essentially warms the bee s wings up in preparation for flight. Bees tend to spread out before their departure, decreasing their overall density. A study conducted in 2007, by Visscher and Seeley, investigated the division of labor, specifically relating to the worker piping signal. The study examined two alternative mechanisms to relay to the hive that takeoff is eminent. Perhaps nest site scouts are solely responsible for communicating this signal to the hive or the signal is produced in a wave-like fashion where one individual triggers the signal and the next individual reacts. The researchers marked scouts visiting the nest site and observed their behavior. To ensure complete control over the experiment, they provided the colony with a single nest site on an island off the coast of Maine. In all of the trials carried out with multiple hives, the number of scouts correlated to the number of marked scouts. Overall, they found no evidence suggesting a relay of communication throughout the entire hive. Bees that have visited the potential nest site, themselves, only carry out piping signaling. This suggested another communication mechanism must be present prior to take off to inform the entire hive of the departure (Visscher and Seeley 2007). Ten minutes prior to takeoff, the movement of bees drastically increases via their production of another critical signaling mechanism, the buzz-running signal (Rangel and Seeley 2008). The buzz-runner s job is to awaken motionless bees by running through a group and promoting movement. The buzz-running signal is a critical step in preparing the bees to launch. The runners enhance their contact with the group by moving in a zigzag motion while actively buzzing their wings. Interestingly, Seeley and Rangel proposed an alternative mechanism for

9 de Ridder 9 initiating the flight; i.e. chemical signaling. A study in 2007 showed that the infamous waggledance is not simply an acoustic/mechanical mechanism but also has a chemical component (Thom, et. al. 2007). The piping and buzz-running signals may potentially have a chemical signal involved in initiating the swarm s coordinated movement, but evidence for this theory has not yet been reported. Conclusion Ultimately, current research has shown that the hive dynamic is much more complex than a simple dictatorship; indeed, one could even argue that the bees represent a truer democracy than the United States itself. In fact, consensus building is often not the form of democratic decision-making seen with human politics. Often, two political parties or two similarly inclined groups will form concrete opinions in which they stand at opposing ends. Soon thereafter, a group must make a majority-rule decision to transform the two choices into one single resolution. This form of democracy arises from individuals with opposing personal interests. The democratic decision-making process exemplified by honeybees arises from a group with one uniform interest, the safety of the hive and the best possible location for a new home. The bee is an individual, in every sense of the word, with opportunity for opinion and even feedback upon such. No representation other than one s own ideas and the ability to voice them are required. Advanced behavior and chemical signaling practices demonstrate that this undoubtedly vital population may even be the envy of human societies; for what community of man can so quickly and effectively decide upon a new home for all involved, much less actually move a population of bodies in such an effort? It is clear that these findings merit further research into the hive paradigm; it is even possible that greater insight might provide more useful methods of

10 de Ridder 10 preventing their slow decline into extinction and consequent damage to ecosystems by increasing inability to fulfill widespread, necessary pollination syndromes.

11 de Ridder 11 References Bogacz, R., E. Brown, J. Moehlis, P. Holmes, and J.D. Cohen. The physics of optimal decision making: A formal analysis of models of performance in two-alternative forced-choice tasks. Psychological Review Vol. 113, pp Britton, N.F., N. R. Franks, S. C. Pratt, and T. D. Seeley. Deciding on a new home: how do honeybees agree? Proceedings of the Royal Society of London B. Biological Science Vol. 269, pp Johnson, B. and E. Frost. Individual-level patterns of division of labor in honeybees highlight flexibility in colony-level developmental mechanisms. Behav. Ecol. Sociobiol Vol. 66, pp Jorgen, R., H. Olofsson and N. Jonzen. What is bet-hedging, really? Proceedings of the Royal Society of London B. Biological Science Vol. 277, No. 1685, pp Rangel, J. and T.D. Seeley. The signals initiating the mass exodus of a honeybee swarm from its nest. Animal Behaviour Vol. 76, pp Schlegel, T., P. K. K. Visscher, and T. D. Seeley. "Beeping and piping: characterization of two mechano-acoustic signals used by honey bees in swarming." Naturwissenschaften Vol. 99:12, pp Seeley, T. D. & Buhrman, S. C. Nest-site selection in honey bees: how well do swarms implement the best-of-n decision rule? Behavioral Ecology and Sociobiology Vol. 49, pp Seeley, T. D. The Wisdom of the Hive Cambridge, MA: Harvard University Press. Seeley, T. D., P. K. Visscher, and K. Passino. Group Decision Making in Honeybee Swarms. American Scientist Vol. 94, pp Seeley, T.D., P. K. K. Visscher, T. Schlegel, P. M. Hogan, N. R. Franks, and J. A. R. Marshall. "Stop Signals Provide Cross Inhibition in Collective Decision-Making by Honeybee Swarms." Science Vol. 335, no. 6064, pp Thom, C., D.C. Gilley, J. Hooper, and H. E. Esch. The scent of the waggle dance. PLoS Biology Vol. 5, pp Visscher, P. K. Group Decision Making in Nest-Site Selection Among Social Insects. Annual Review of Entomology Vol. 52, pp Visscher, P. K. & Camazine, S. Collective decisions and cognition in bees. Nature Vol. 397, pp. 400.

12 de Ridder 12 Visscher, P. K. and T. Seeley. Coordinating a group departure: who produces the piping signals on honeybee swarms?. Behavioral ecology and sociobiology Vol. 61, no. 10, pp

Heterogeneity and Value-Sensitive Collective Decision-Making

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