Sex on Six Legs_ Lessons on Life, Love, and Language From the Insect World - Marlene Zuk [12]
Honeybees have long been known to navigate using landmarks and use information from each other to find food, as I discuss below and in another chapter, but a recently discovered ability deserves special mention: they can count. The ability to enumerate objects is considered one of those gold standards of intelligence by scientists, and several kinds of primates, some other mammals such as dolphins and dogs, and psychologist Irene Pepperberg's late African gray parrot, Alex, have been shown to do so. Still, you just don't think about insects in the same breath as you do arithmetic. But scientists Marie Dacke and Mandyam Srinivasan of the Australian National University in Canberra trained the bees to fly down a tunnel toward a food reward, using landmarks set along the walls and floor. To get to the food, the bees couldn't simply memorize the position of the landmarks, because the locations of the landmarks were shifted every 5 minutes. Instead, the bees had to learn that the food could be found at the base of landmark number 1, 2, 3, 4, or 5, depending on the individual experiment. Counting to four was mastered relatively easily, but getting to five proved challenging. Nonetheless, that the bees could generalize to a number at all, rather than simply flying until they saw an object in the same place it had been before, is an extraordinary accomplishment.
The bees' ability is exciting not only because it helps demolish that boundary of the backbone with regard to intelligence, but because being forced to design the experiments required to demonstrate counting in a creature so different from us makes us strip down our methods to their essentials. Finding out if your three-year-old can count is one thing. But how do you come up with a test for counting, or learning in general, when your subjects can't talk, walk on two legs, point to anything, or even get rewarded with something they want, the way most people can? If we can design ways to study animals with these limitations, maybe it will help us work more effectively to test humans with limited abilities, or even design computer programs that could substitute for the abilities that are lacking.
Figuring out exactly how to test insect intelligence in a way that is meaningful to them but also tells us something is challenging. Reuven Dukas, a biologist at McMaster University in Canada, has studied learning in a wide variety of insects and thinks we may only be scratching the surface of their abilities. After all, if insects don't learn something, he says, echoing teachers everywhere, "Is it because I'm not a good teacher or because the animal doesn't learn?" It's always hard to know what tasks an animal will be able to perform that we can then generalize to other species. Jan Wessnitzer and colleagues from the University of Edinburgh showed that my favorite insects, crickets, could relocate a particular spot on the floor using objects in a photo along the wall of their experimental arena as landmarks—the best navigational aid was a rather stark landscape that looked like a desert in the American Southwest. The training scheme they used consisted of a floor heated to an uncomfortable temperature except for a single cooler spot that the crickets presumably preferred to stand on. It was called, without comment, the Tennessee Williams paradigm.
The Face Is Familiar, but What about the Antennae?
LEARNING about food sources is one thing, since it is a natural behavior