The lesson of p. punctatus

Immigration advocates never seem to take into account that the putative benefits of immigration depend entirely upon the characteristics of those entering the society en masse.

In a recently published paper in PNAS Early Edition, Dobata and Kazuki Tsuji demonstrate what they believe is the first observed public goods dilemma observed in a non-human and non-microbial system.

By using the social ant Pristomyrmex punctatus, they were able to show the fitness consequences to the colony and track the shifting genetic make-up as cheaters invaded and took hold. Researchers have recently evaluated these questions in systems involving viruses and cells (where cells may secrete protective substances, or self-destruct to form a spore-dispersing stalk) but not in multicellular organisms before. Yet the results are so similar, write Dobata and Tsuji, that they believe universal principles are at play.

P. punctatus is a curious species. The queen caste, morphologically and functionally distinct in most social insects, has been secondarily lost. All workers are involved in both reproduction and cooperative tasks like foraging. There is still a division of labor, among age groups. Young workers take care of inside-nest tasks, which include asexual (thelytokous) reproduction. Older workers ease out of reproduction and shift to tasks outside the nest, like foraging.

But there is a third kind of P. punctatus. A group of cheaters, made of a single intraspecific lineage in the field, that engage in very few tasks, save for reproduction.

The researchers found when these genetic cheaters infect a colony they have better individual fitness than the workers, both in terms of survival and brood production. They reduce worker survival and reproduction, as more young workers shift to tasks outside the nest to effectively pick up the slack. Eventually, the cheater hordes take over. The authors call the cheaters a kind of  ”transmissible social cancer.”

In cheater-only colonies, more eggs are initially produced, compared to worker colonies, but they are neglected. Eggs begin to rot and the nest becomes a dirty, unhygienic place. Eventually, the nest dies. For a group, cheating is an evolutionary dead end.

Compare the global North to the global South. Then consider whether the immigrant communities of today more closely resemble meticulous productive ant nests or dirty, unhygienic places. Ants might not be able to anticipate the idiocratic consequences of allow a “transmissible social cancer” to take root in their colonies, but one would have thought that human beings could do better.

When a society’s social policy is a scientifically predictable evolutionary dead end, it should invite rethink. Instead, questioning it is deemed akin to blasphemy. This is not the hallmark of a society destined for survival.