Bees are not Social

I was recently in a debate about the nature of society. My opponent used the analogy of a beehive to claim that altruism exists in nature. This analogy is common in discussions of human society. It is a bad analogy, so I thought I would debunk it. Also, bee biology is fascinating.

There is something very unusual about bee genetics and sex determination. The females are diploid and the males are haploid. A female bee has two copies of each chromosome, but a male bee has only one copy of each chromosome. Male bees grow from unfertilized eggs. This arrangement is called “haplodiploidy”.

There are three kinds of bees: queens (fertile females), workers (infertile females) and drones (fertile males). Evolution has provided the queen bee with the ability to create infertile offspring to help her out. The queen has control over which eggs to fertilize with sperm stored from mating. Fertilized eggs grow into females. If a female larva is fed royal jelly, it will grow into a queen. Otherwise, it will grow into a worker. Unfertilized eggs grow into drones.

The drones are pure extensions of the queen, because they only carry her genes. A male’s genes are from its mother. A female’s genes are from its mother and its father’s mother. As I will explain, it is useful to think of a worker as the “offspring” of two queens: its mother and its grandmother.

In humans, the Y chromosome never passes through a woman’s body. Its genes were never selected for the ability to help females reproduce. In bees, all genes pass through a female body at least every second generation. In most cases, that female body is a queen. This means that all bee genes are selected for their ability to help queens reproduce.

We can think about the queen bee as really the only kind of bee “individual”. The workers and drones are merely extensions of her. She has the ability to create workers that help her to build and run the hive. She also has the ability to generate male children that try to mate with other queens.

But why do the workers go along with this deal? After all, the workers inherit two sets of chromosomes, one from a drone and one from the queen. Why don’t the father’s chromosomes in the worker cause her to rebel against the interests of the mother’s chromosomes?

Suppose that a worker (we’ll call her “Sally”) inherits a gene that makes her defect on the “hive contract”. Sally puts all her energy into laying her own unfertilized eggs, thus creating drones with her genes. What happens to those genes? If Sally’s male offspring get lucky, they will mate with a queen that creates a new hive. But the new hive would not work very well, because some of its workers would inherit the defector gene from their grandmother Sally. The defector gene would be selected against — not in Sally’s lifetime, but in the lifetime of her grandchildren. Sally could have many children, but she would not have many grandchildren.

Since worker genes are normally inherited from queen mothers or grandmothers, all bee genes have been selected for the ability to produce loyal workers. Female bees are dimorphic: they have two different forms that are expressions of the same genotype. The genes that create the worker form are also present in the queen. They benefit the queen when they are expressed in her children.

Workers do sometimes rebel against the queen by laying unfertilized eggs that could hatch into drones. These eggs are usually eaten by other workers, which is called “worker policing”. Defection does occur, but it is not common. Defector genes can be passed on from defector workers to drones to new workers, so this variant reproductive strategy can persist at a low frequency in the population. But most workers put their time and energy into raising the offspring of the queen, because that behavior has been selected for.

Drones, on the other hand, live only to fuck. The chances of having sex on a mating flight are extremely small, but the payoff is huge: becoming the father of a new hive. So, each male bee is dedicated to this mission. He is a pure representative of his mother, because he carries only her genes. You can think of a drone as just a vehicle for the queen’s genes. His sperm cells are clones of him, because he is haploid. A drone is really just an embodied sperm: the sperm of his mother.

Worker bees occasionally make new queens by feeding female larvae royal jelly. When a new queen emerges from her cell, her first mission is to kill any larval queens in the hive. Her post-larval life begins by killing her sisters. The workers might try to save the other queens, but they won’t kill the first-born queen because she is their legacy. After killing her royal sisters, a virgin queen typically leaves the nest and goes in search of a mate. She mates with some number of drones on a mating flight, and then settles down to create a new hive.

Bees are not “social insects”. It would be more accurate to call them “weird family insects” or “multi-bodied organisms”. The hive as a whole, with the queen as its focal point, is a kind of super-organism that reproduces as a unit. Hives beget new hives. What we view as the individual organism, a single bee, is not the unit of reproduction.

Although a beehive is analogous to a single organism, it is not as functionally coherent as a multicellular organism. The cells in your body work together, without conflict or cheating, because they all descend from a single cell by cloning. Also, your body cells cannot reproduce by themselves, in the long run. They all descend from a zygote that was created by sexual reproduction, and they can only reproduce, in the long run, by contributing to the creation of a new zygote. Sex is a reproductive bottleneck. That is why your cells all work together in a coordinated way. Their reproductive interests are the same. Cells in your body die every day for the greater good of the body. That might appear to be altruistic, but it isn’t. It is reproductive selfishness.

Nature doesn’t do nice. Nature doesn’t do altruism. Nature only creates selfish reproducers.

Unlike bees, we are not multi-bodied organisms. We reproduce as individuals. Our societies are nothing like beehives, and beehives are nothing like societies. Society is based on cooperation between selfish individuals, not altruism or shared genetic interests. Society consists of selfish individuals with different interests working together for their mutual benefit.

A beehive is not analogous to a human society. Bees are not social.