麻豆淫院

Researchers from the Cluster of Excellence Collective Behavior at the University of Konstanz have discovered that honey bees from the same colony have different preferences in terms of defensive behavior. While some are still hesitating, others are already attacking.

Honey bee colonies are well organized. Some collect nectar, others water, a few fan the hive with air to cool it down鈥攁nd some defend the colony by stinging enemies. But when exactly does this happen? And do some individuals have a greater propensity to attack than others? A research team from the University of Konstanz is investigating these questions in more detail.

In a recent study in Royal Society Open Science, the researchers have now discovered that there are bees that attack, while other conspecifics always stay calm. They also show how social factors regulate this decision and that the personality of the individual bees is more important for the group dynamics than assumed.

For her research, doctoral student Kavitha Kannan at the University of Konstanz, led by neurobiologist Morgane Nouvian, specifically captured guard bees at the university's own beehives. The idea was to have a homogeneous group with assumed identical stinging behavior.

"Basically, you can expect that, simply by the distribution of tasks, a collector will have a different stinging behavior than a guard. As we wanted to exclude as many influencing factors as possible, this selection was the first logical step. We were then able to gradually test other influencing factors," explains Kannan.

One bee sounds the alarm, but not everyone follows

The researchers knew from previous studies that the animals are influenced by pheromones. If a bee decides to sting, an alarm pheromone is released that encourages other bees to do the same. With each additional sting, the concentration of this pheromone increases, which in turn provides information on how many bees are already involved in the attack.

Studies have shown that after a certain concentration has been reached, the stinging behavior starts to decrease. Especially in view of the fact that bees usually lose their stinger after using it and consequently die, this is a sensible method to prevent mass mortality as a result of an attack. According to studies, the likelihood that a bee will respond to a given concentration of alarm pheromone also depends on the size of the group.

What had been unknown so far is how the bees decide which of them will ultimately sting. The results of the current study by Nouvian suggest that the personality of each bee plays a major role in this context. "We simulated several situations in our tests in order to gradually explore various influencing factors," explains Nouvian.

To provoke the bees to sting, the team used dummies in which the bees' stings did not stick. This way, the animals could be repeatedly exposed to such situations in order to verify their respective reaction and rule out random behavior.

Blend in or stand out

"In one group, for example, we tested whether stinging behavior was affected by the presence of a conspecific, and in another group we tested the effect of the alarm pheromone," Nouvian says. "Ultimately, it turned out that although these factors had an influence, they did not impact the predictability of individual stinging behavior."

The respective personality therefore prevailed over conformism. This was also confirmed in a final experiment where the researchers determined that bees did not change their stinging behavior as a function of group composition. Thus, even honeybees, which are renowned for their highly social lifestyle and for putting the needs of the colony before their own, retain some individuality.