Intelligence in Nature - Jeremy Narby [24]
Scientists often use the concept of âinstinctâ when explaining the capacities of animals. I asked Giurfa if he found it useful in his work. He said that he had started his work in Berlin by studying a question related to bee instinct, looking into whether or not bees have information encoded in their brains when they take their first exploratory flight. Giurfa built a large apiary containing a small beehive in which all external conditions are controlled and went on to demonstrate that bees spontaneously prefer certain colors, in particular very intense blue and yellow. These colors correspond to the flowers richest in nectar. So instinct exists, Giurfa said, and is a useful concept. But Giurfa also found that bees can modify their instinct according to what they learn about the world. In the controlled environment he constructed, Giurfa arranged for pollen to be associated with other colors and found that bees can modify their color instincts. âWe see the incredible plasticity of the system,â he said. âThis means that they go into nature equipped with instinctive information, which is not rigid, and which they can forget or put aside on the basis of personal experience, meaning to say on the basis of learning.â
A loud hammering echoed through the ceiling. Upstairs, workers were bringing down a wall. Toulouse University was remodeling its Animal Behavior Department, turning it into a âlaboratory of animal cognition.â I took this as a sign of the times. Science is opening up to the intelligence of other species, and this is bringing down university walls, literally.
Giurfa turned to his computer and summoned up a full-screen image of the internal organization of the bee brain. He explained that a key part of their research involves looking into bee brains in search of the âneuronal substrateâ of a given behavior. For scientists, the great advantage of the bee brain is that it can handle complex mental tasks with less than a million neurons. This simplifies research. Working with brain-imaging techniques, Giurfa and his colleagues mapped which parts of the bee brain are active when the animal learns about the smell of the outside world. Their research revealed the existence of a sensory-integration center called the âmushroom body,â which is made of 170,000 densely packed neurons. This central component of the bee brain receives sensory input and directs behaviorsâsuch as when bees dance symbolically to communicate information about the location of pollen-laden flowers, or navigate over long distances according to the sunâs position in the sky, or estimate the quality of potential nest sites.
Giurfa explained that they looked into the bee brain using a technique known as calcium imaging. Given that active neurons exchange calcium, one can open the skull of a living bee and bathe its brain in fluorescent substances that latch onto calcium and reveal the active parts of the brain. âThis is another advantage of invertebrates,â he said. âThis process does not affect the animal. Invertebrates are enveloped in a capsule; their whole body is a capsule that is not innervated. It is very hard for us to imagine, but that is how it is. Imagine that instead of having skin, which is sensitive because it is innervated and filled with nerve endings, we had our internal system in armor.â
âSo the nerves stop with the brain?â
âExactly. If you open it, if you make a small hole in a beeâs head, it is just like taking a helmet off. You