Bee Intelligent

I remember a biology lesson when our schoolteacher laid out a row of pickled brains.  The lids of some jars were leaking formaldehyde vapor into the classroom, an irritating odor that I had to get used to after I started working along the corridor from the anatomy dissecting room at the Edinburgh Medical School.  But that day we only saw brains from a sheep, rabbit, dog, and mouse, and nothing as mesmerizing as a human brain or as minute as a bee’s.

Honey bee brain
Honey bee brain

The class was asked to place the brains in order from the smartest to the dumbest. Everyone voted for dogs at the top spot, even though their brains are only half the size of a sheep’s. Dogs are quick learners and can round up a stupid flock: it’s never the other way round!  Evidently a larger brain is not always gain.

One of my classmates piped up trying to impress our teacher, “Sir, isn’t intelligence hard to define and measure?”

“Not at all…”, he replied.

I can’t remember now the definition he gave except it was so anthropocentric I found it hard to relate to animals. And he believed the only reliable way to measure intelligence was using an I.Q. test. In those days, boys were still slightly in awe of teachers so no one dared ask the impertinent question: what does an I.Q. test for a Border Collie look like?

After graduating from high school, the boy who asked the question went on to a roaring success, as we expected, but not all the bright students who performed well in examinations in our boys’ school fared as well at college or afterwards. I wondered why. Now I know there’s more than one kind of intelligence – at least nine, so they say, but I shall add another. My classmate was right after all – intelligence isn’t simple, and sometimes “simple” is smart.

Our species doesn’t always get straight A’s in tests: sometimes animals are streaks ahead of us. Chimpanzees have better short-term memories for numbers and their positions on a screen test, and my Golden Retriever beats me in emotional intelligence (call it what you will). Like others of her kind she has an amazing ability to anticipate my actions even before they come into my mind, presumably having learned subtle cues of which I am unconscious before, say, taking her for a walk or feeding her. Owning a pet gave me more respect for animals than anything I ever learned in a biology class.

Bees too are intelligent – really? A honey bee “brain” is merely a string of ganglia containing fewer than a million nerve cells. The average canine brain contains thousands of times more cells. But many people claim that bees are intelligent, and as a new beekeeper they certainly fill me with awe. I wonder what my classmate would think now: would he say their nervous system is capable of anything more than instinctive behavior?

Routine inspection
Routine inspection

When a guard bee attacks my bee-suit like a kamikaze pilot while I am inspecting its hive, it is obeying an instinct that has been honed during millions of years of evolution. Since it didn’t have to learn this behavior I can’t call it “intelligent” any more than a military drone, except when there’s a human controller behind it. To call bees smart there must be evidence that they can learn from experience, and they can – collectively. They have a social intelligence based on the thousands of workers, a few hundred drones, and the single queen in a colony. I like to compare a colony with a body in which all the necessary functions for health and survival are divided between organs – brain, heart, liver, et cetera. In a hive or swarm, the responsibilities are split between guards, nurses, foragers, and an egg-layer.

If you watch an active hive you will soon be impressed by its orderly life, like a healthy body at work. Such smooth running requires a lot of communication through smell, touch, and sight, of which the most famous example is the waggle dance. Bees returning from foraging for food pass information to others by “dancing” for them, which is a kind of sign language conveying information about the direction, distance, and even the quality of a source of nectar or pollen.  This behavior increases foraging efficiency for the whole colony which would otherwise have to search randomly for food. And when bees go out again to forage a cognitive map in their tiny brain remembers where the good stuff can be found, and the best time of day to go. As impressed as I am with my smart phone, no manufactured mobile device I will ever own will be as clever.

The latest buzz is that bees can use the waggle dance as coded information to advise the colony where to relocate. When accommodation in a hive or a natural nest has been fully occupied the colony swarms to search for a new home, taking lots of honey with them. This is a beekeeper’s nightmare at this time of year after we recently celebrated the survival of our hives through the winter.

Checking for queen cells (peanut-shaped cells at base of frame) before "splitting" a hive to discourage  swarming
Checking for queen cells (peanut-shaped cells at base of frame) before “splitting” a hive to discourage swarming

Tom Seeley of Cornell University wondered how a swarm decides where to hive off to.  He chose for his study an island several miles offshore from Boston where there were no existing bee colonies or natural nest sites (no trees). His research team marked hundreds of bees with a colored ink spot on the thorax so the peregrinations of scouts from several swarms could be traced around the island. Then he set up hives, but some of them were much more hospitable sites than others.

Scout bees, being the oldest and “wisest” workers, searched for nest sites all over the island. When they returned they started dancing a coded message for the swarm, but how did it decide which scout had found the best home for them? The researchers noticed that the scouts that danced the longest were proposing the best quality nest sites, and they almost always rendered honest advice.  The colony reached its decision where to nest by vox populi or “interviewing” all the scouts: it seems an incredible blow to our pride that bees invented democracy millions of years ahead of us. The upshot of the study was that 19 times out of 20 they wisely chose the best site.

Swarm intelligence enables honey bees to make the life-or-death decision of finding a home that is safe from critters and the elements. So bees are bright. A swarm weighs about the same as a human brain, but humans can be rather lacking in collective intelligence, and often in trying to make a decision our judgment is poor and we create chaos and strife.

Next Post: Drive and Text, and Let Die

Winter bee-line

T.S. Eliot was wrong: February is the cruelest month, not April.

When one of our sister bee hives in the Yorktown churchyard was opened recently the entire colony was found to have died. Several thousand bees were strewn across the frames and base. Our local expert warned that this is a tough time of year for bees, which can starve to death despite having honey in the comb or kindly keepers who leave candy for them. Sometimes, he told us, they starve within inches of plenty.

This sad news put me in mind of a teacher’s favorite story when I was a fifth grader in England. A hundred year ago, Captain Robert Scott leading a small band of Antarctic explorers was returning to base feeling dejected after being beaten to the Pole by Norwegians.  During a ferocious blizzard they froze to death just eleven miles from the safety of a depot, their bodies still entombed to this day in the Ross ice shelf which is slowly migrating to the sea.

I always thought Captain Oates played a supremely heroic role before their final camp because he walked out to his death so that his frost-bitten legs wouldn’t slow the party down. That’s another reminder of the life of a bee, who lays down her life for the colony with one, and only one, sting. Altruism in nature was something that used to stick in the gullet of evolutionary theorists like a fish bone, but it’s not such a mystery in bees because they are genetically-related. Self-sacrifice makes genetic sense if it helps siblings to survive. But to think that each bee is as much an individual as, say, a dog or ourselves is misleading: a hive is more like a superorganism with different castes of bees playing roles equivalent to the organs and limbs of our bodies. Put that way, I don’t feel so guilty when I accidentally squash a few of the ‘girls’ putting the lid back on their hive.

Perhaps self-sacrifice in bees is more like the shedding of a lizard’s tail after it is grabbed by a predator. On second thoughts, that’s not such a brilliant analogy.  Bees are not genetically identical, like clones, because although they are all derived from the same bag of genes in the queen the genes have been reassorted by meiosis in eggs.

Bee
Bee up close

Our surviving hive is thriving (the other was mysteriously evacuated last September). On warm days foragers leave for polligrinations over several square miles of territory. They return with payloads of nectar and golden sacs of pollen stuck to their body, which are passed to nursemaid bees to feed the larvae. Even in mid-winter they find flowers when I can’t see any.

While most insects and other cold-blooded creatures hibernate to conserve energy, bees are busy whenever the temperature rises above the forties. It’s imperative! Already sensing the longer days, they have started to expand their colony in a race against time. The hive needs more workers; it must raise numbers from a few thousand to forty thousand or more so it can manufacture enough honey to store for next winter (and for us!).

The queen lays up to 1,000 eggs per day, about one every minute. Like poker played for high stakes, she goes all in. It takes 42 days for an egg to grow into an active worker, so she is fully employed now preparing the hive for the large flows of nectar starting in March. Now when I see a hive standing cold and silent I know the heart of the superorganism is beating fast while almost everything around is in the deep sleep of winter.

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 Knight Bruce has lent me a grand observatory hive; and I am going to watch.

Letter from Charles Darwin to his son, Willy (May 26, 1858)

Next Post: A Dog’s Dinner

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