Humans are hive enthusiasts. We love social insects like ants and bees, and we pay extra attention to Star Trek episodes when the you-will-be-assimilated Borg are featured. But what exactly is so interesting about hives? They’re interesting to us because, en masse, they amount to a superorganism, with analogs to organisms at the genetic level, reproductive level, and the behavior level. Also, just as larger, more complex, organisms tend to have a greater number of specialized cell types, larger ant colonies tend to have a greater number of “ant types” (see the figure).
And in new research this week in the Proceedings of the National Academy of Science, Chen Hou from Arizona State University found that the metabolic rates of ant colonies follow the same law – Kleiber’s Law – that solitary-living insects follow concerning how metabolism scales with body mass. Metabolically, colonies act like superorganisms rather than just big groups of organisms. Ant colonies really are organisms.
Why, though, should we find that fascinating? If ant colonies are organisms, then they should get imbued with the same level of interest we find in the average organism. To understand what makes social insects especially exciting, we must get inside our own heads, and the perceptions we evolved to possess.
In addition to the perceptions you may have heard about – like color, motion and form – we have intrinsically much more complicated perceptions. Face recognition is one example, but relevant to our purposes here is the perception of “animacy”. Certain stimuli elicit perceptions in us of there being a living, animal-like, thing. Even a simple square moving about can elicit this kind of perception, so long as it moves in a sufficiently animal-like fashion.
But there is one thing our “animal perception” requires that ant colonies and the Borg violate: Animals must be solid objects. To be an animal, our perceptual system demands that the constituent cells must be physically connected, not merely be informationally connected. Hives do all the requisite information interconnectivity without having to be physically touching, and although that is a difference that makes no computational difference, it makes all the difference in the world to our perception.
Our perceptions of animacy lead us to the conclusion that the ant drones are the animals, not the colony itself. That is what makes social insects so interesting: social insects are cases of animals that don’t fit our evolved perceptual expectations for animals. What makes social insects and the Borg so interesting is, then, more about our perceptual apparatus than it is about the intrinsic coolness of ants or assimilation.
And if hives can be exhilarating to our brains for perceptuo-cognitive reasons, then we can exhilarate in the other direction. Rather than concentrating on the animal-hood of colonies, let’s ask about the colony-hood of animals. Animals are, after all, massive colonies of cells. The problem with thinking of animals as cell colonies is that even if we could see individual cells, cells don’t have the animal-like properties ants do, and thus cannot tap into our animal perceptions.
Or can they? Cells do often behave in an ant-like animal fashion, but just move too slowly for you to perceive their animal-likeness. When one views videos of cells in a a growing animal, and the video allows us to see the individual cells moving, animals begin to look instead like colonies of cells. Take a look at the second and third video here — http://pr.caltech.edu:16080/events/kulesa/ — showing cell movements in the developing chick embryo from the laboratory of Paul Kulesa. (In fact, download the videos to your computer first, and then play, so that you can make the video larger.) You will see, especially in the third movie, individual cells poking about, and at this spatio-temporal scale your animal perceptions are activated, and the chick is no longer an animal, but is perceived instead as a colony of single-celled animals.
This first appeared on January 24, 2010, as a feature at the Telegraph.