and also form close bonds with one another; in other words, the ones that live alongside many others in a community. These critters must constantly be making judgements: is that yellow thing over there a flower with sweet nectar or is it a peckish crab spider? Will I be able to carry that conifer needle alone or will it take several of us? Do I need to take a sip of this nectar to keep myself going, or should I take it home to Mum?
The social insects divide up jobs, share experiences and ‘talk to each other’ in an advanced way. This requires capacity for thought. To cite Charles Darwin in The Descent of Man: ‘The brain of an ant is one of the most marvellous atoms of matter in the world, perhaps more so than the brain of a man.’ And that was without knowing what we now know: that ants are capable of teaching skills to other ants.
The ability to teach has long been seen as exclusive to us humans, almost a proof of an advanced society. Three quite specific criteria distinguish teaching from other communications: it must be an activity that only happens when a teacher meets an ‘ignorant’ pupil; it must involve a cost for the teacher; and it must make the pupil learn more rapidly than he/she otherwise would have. The term is used for communication about concepts and strategies, so the honeybees’ dance (see here), which is more about process, is generally not viewed as teaching. However, it turns out that ants are capable of teaching things to other ants, through a process known as ‘tandem running’, in which an experienced ant shows the way to food. This occurs in a European species, Temnothorax albipennis, which relies on landmarks such as trees, stones and others, as well as scent trails, to remember the way from the anthill to a new source of food. In order for several ants to be able to find the food, a she-ant (all worker ants are female, see here) who knows the way must teach it to the others. The teacher runs on ahead to show the way, but constantly stops to wait for her pupil, who runs more slowly, apparently because she needs time to take note of the landmarks they are passing. When the pupil is ready again, she touches the teacher with her antennae and they continue on their journey. The behaviour therefore satisfies the three criteria of ‘genuine teaching’: the activity happens only when a teacher meets an ‘ignorant’ pupil, it involves a cost for the teacher (she must stop and wait) and it makes the pupil learn more quickly than she would have on her own.
Bumblebees have also recently been inducted into the exclusive little group of creatures who can teach tricks to their peers. Swedish and Australian scientists successfully trained bumblebees to pull on a string to gain access to nectar. They made artificial blue flowers in the form of plastic discs, which they filled with sugar water. When these were covered with a transparent plate of plexiglass, the only way of gaining access to the sugar water was to pull on a string attached to the fake flower. If the scientists only let untrained bumblebees loose on the covered flowers, they didn’t understand a thing: none of them pulled on the string. A great starting point. Then the bumblebees were given a chance to get acquainted with the ‘flowers’, learning about the reward they offered. Gradually, the fake flowers were pushed further and further beneath the transparent plexiglass plate. This time, when the fake flowers were finally pushed fully beneath the plate, 23 out of 40 bumblebees began to pull on the string. In this way, they drew the fake flowers out and were able to suck up the sugar water. Admittedly it was a long lesson: the whole business took a good five hours of training per bumblebee.
The next step was to see whether these trained bumblebees could teach others their peculiar trick. Three bumblebees were selected as ‘teachers’. New, untrained bumblebees were placed with them in a small transparent cage close to the flowers to watch and learn. Fifteen of the 25 ‘pupils’ grasped the point by watching how their teacher did it, and they too managed to pull out their reward when they got to have a go afterwards. All in all, this experiment showed both that the bumblebees could learn this rather unnatural skill and that they were capable of teaching the strategy to others.
Clever Horse Hans and the Even Cleverer Bee
Hans the Horse of Germany was a global celebrity in the early 1900s. He couldn’t just count, he could also calculate – or so people thought. The horse could add, subtract, multiply and divide. He answered arithmetic problems by banging out the correct answer with his foreleg, and his owner, maths teacher Wilhelm von Osten, was convinced that the animal was just as clever as himself. In the end, it turned out that Hans couldn’t calculate at all or even count. That said, he was a whiz at reading the minuscule signals in his questioner’s body language and facial expressions. The person setting the problem had to count too, to make sure that Hans was giving the right answer, and a tiny, unconscious signal he made when the horse reached the correct number was all that Hans needed. In fact, not even the psychologist who eventually unmasked Hans was able to control these signals.
However, bees actually can count according to new research. Not very far, and they are no more capable of the four types of calculation than Hans was. Even so, it’s a pretty impressive feat for a creature with a brain the size of a sesame seed. To measure this, honeybees were placed in a tunnel and trained to expect a reward after passing a certain number of landmarks, regardless of how far they had to fly. It turned out that bees could count up to four, and once they had learnt to do that, they were able to count the landmarks even if they were a new type they had never seen before.
And bees aren’t just good at maths (well, considering their size), they are also good at languages.
Dancing Bee People
At around the same time as von Osten and his not-so-clever horse were alive, a future Nobel Prize winner was growing up in the neighbouring country of Austria. Even as a child Karl von Frisch loved animals and his mother must have been extremely tolerant, since she put up with the abundant array of wild creatures he brought home as pets. Over the course of his childhood, he noted 129 different pets in his journal, including 16 birds, 20-odd types of lizard, snakes and frogs, and 27 different fish. Later, as a zoologist, he was especially interested in fish and their colour vision. But almost by chance – largely because his aquatic research subjects displayed an unfortunate tendency to kick the bucket on the way to the conferences where he was supposed to be demonstrating his experiments – he switched to studying bees instead.
Karl von Frisch made two major discoveries: he proved that bees can see colours and that they can tell each other where to find food by performing a sophisticated dance. This was what won him a Nobel Prize in 1973. Von Frisch showed that when a honeybee finds a rich source of nectar, she returns home to the others and tells them where the flowers are. She dances in a kind of figure-of-eight, waggling her rear and vibrating her wings in the parts of the dance when she is moving in a straight line. The speed of the dance communicates the distance to the flowers, while the direction she dances in, in relation to a vertical line, describes where the flowers are relative to the position of the sun.
Today, bees’ dance language is one of the most well-researched and best-mapped examples of animal communication, but history could have turned out quite differently. In Hitler’s Germany, this research was nearly brought to a halt when it had barely begun. In the 1930s, when Karl von Frisch was working at the University of Munich, Hitler sympathisers scoured the university’s employee roster to root out Jewish workers. When von Frisch’s maternal grandmother proved to have been Jewish, he was fired from his post. But he was rescued by a tiny parasite – a parasite that caused a disease in bees that was in the process of wiping out Germany’s bee population. Beekeepers and colleagues managed to persuade the Nazi leadership that von Frisch’s future research was crucial if German beekeeping was to be rescued. The country was at war and in dire need of all and any foodstuffs farming could produce. A collapse of the honeybee population was unthinkable. Thus, von Frisch was able to carry on his research regardless, to the benefit of both bee knowledge and von Frisch’s career.
