Eusocial insects

“Great point about insects. Spooky levels of selflessness.”

Not all insects. Social insects. Or eusocial insects, in the parlance of the trade. I am not sure if there has been altruism observed among other insects, but among social insects a selfless sort of altruism, to the point of suicide, makes perfect sense because  reproduction is typically done via parthenogenesis. That is, reproduction is asexual, so the offspring–the workers–are genetically identical with the queen, and thus a worker’s exact genes are passed on–via reproduction with males–when new queens leave the colony. The various castes in a colony are developed heterochronistically, where hox genes change the rate of development. You can see that in the various sizes of ants boiling out of a nest. Big ones with huge mandibles are soldiers, most workers are medium sized, while smaller ants and even tiny ants all have their roles in the colony. Everyone has the same genes, but alterations in the growth rates within those genes time their development. Just like in human beings. Heterochrony even assigns us our roles at times. Hypermorphosis creates big tall guys who become professional basketball players. Neoteny creates jockeys. But where male hypermorphosis among us is driven in large part by sexual selection, that is not a factor in ant parthenogenesis. Everyone in an ant colony is genetically identical, and almost none of them will ever have sex anyway. That is left to the queens and males. The rest are just there for the gig, workers mostly, some soldiers. There is actually a lot more variation in individual ant behavior than we might assume–some ants just hang around inside the colony, doing as little as possible–but their roles are decided for them. A worker can no more be a soldier than a basketball player can be a jockey. Yet its that immutable caste system that gives the ants their staying power. Their colonies are not machines, not computer programs, but are what E.O. Wilson calls super-organisms, a whole bunch of tiny little organisms that together act nearly as one. Taken to its furthest extent, the power of an ant colony can be extraordinary.  

The Argentine ant supercolony, the ants that drive Californians nuts with their endless invasions, stretches along the California coast, the southeastern coast of Australia and along vast stretches of the western Mediterranean. It is estimated to number billions of individuals, as as many ants as there are human beings–except that every single ant within it, from San Diego to Sidney to Marseilles, is genetically identical. Obviously we human beings are not. Our very development as a species was dependent on the fact that we are not identical. It’s hard to imagine how homo sapiens could ever have survived without genetic variation. Disease itself would have annihilated us. But a single colony of genetically identical Argentine ants seems to be taking over the world…or the parts within climate zones it can survive, and it has increased its population to as many individual ants as there are people and it is genetically identical. Somehow, it works for them. That is the beauty of the eusocial ant business model. Then again, it seems inevitable that something will eventually exploit that lack of genetic variation throughout the entire Argentine mega colony and tear into its impregnability the way the Roman Empire was gutted by Goths, Vandals, Persians and plague in its Crisis of the Third Century. And if this could happen before the Argentine Ant Empire permanently conquers the kitchen in our own household version of the Crisis of the Third Century, I wouldn’t mind.


Argentine ants, working.