August 29, 2013 | 1
In my previous post, I talked about how crickets were influenced by who was watching them when they performed a victory dance after winning a fight. Although this is a unique finding, it fits into a larger picture of many animals (including insects) being affected by their social context. At the animal behaviour conference I went to in Colorado (where I heard both about the cricket research and about the study I’m going to write about today), you could see how people were affected by what others were doing around them. When one person sneaked out before the end of a talk to go to a talk in a different room, a load of other people would follow. When chatting with a friend, a person would modify what they were saying depending on who else was in the vicinity. Whether we are aware of it all of the time or not, we constantly modify our behaviour depending on the social context we’re in.
Well, in addition to crickets, it turns out that honeybees are affected by social context too. This isn’t surprising, given that these bees are highly social animals, but quite how they are affected is rather interesting.
Honeybees live in colonies of up to 40, 000 – 80, 000 individuals, almost all females. Like humans, honeybees like to keep their dwelling at constant temperature, not least to make sure that their brood can develop. Unlike humans however, bees think around 36°C (96.8°F) is a great temperature to have their home at. In the winter, honeybees shiver to produce heat, pressing their abdomens against their brood (stored in cells) to distribute the heat more evenly. In the summer however, it can get pretty hot, and so the bees use some strategies to cool down that are not dissimilar to our own. They collect water that can evaporate in the colony and cool it down. They also fan to circulate air around the colony. However, until recently it was not clear how bees decide to start fanning, and whether this might be influenced by what others are doing.
Chelsea Cook and Michael Breed decided to look into how it is that bees decide to start fanning to cool their colony down. To see what temperature bees would start fanning at, they placed bees in container and increased the temperature at 1°C per minute starting at room temperature (around 28°C). The bees were either put into the container alone, in a group of three, or in a group of ten. The researchers then watched the bees to see when they would start fanning. They also looked to see whether this differ between different types of bee- because in honeybee colonies the workers have different roles (for example nurse, guard, fanner and forager).
The scientists found that fanning bees were much more likely to fan when they were in larger groups (it was seen in 19% of single bees, 33% of bees in groups of three and 48% of bees in groups of ten). They also fanned at lower temperatures in larger groups. However, this wasn’t the case for foragers- the bees that go and find food for the colony. These bees fanned less than the other bees overall (even when in groups of ten), and did not fan more in larger groups.
This is the first study to find that a honeybees’ tendency to fan is affected by what the other bees are doing around her. This makes sense, because as a highly social species, behaviours done in isolation aren’t much good- it’s the coordination of behaviours that matters. This finding could indicate that perhaps other honeybee behaviours are affected by the social context that they’re in too.
honeybee photo: Paul Stein
videos: Chelsea Cook
Cook, C. N., & Breed, M. D. (2013). Social context influences the initiation and threshold of thermoregulatory behaviour in honeybees. Animal Behaviour.