The evolution of altruism and the serial rediscovery of the role of relatedness

Abstract

The genetic evolution of altruism (i.e., a behavior resulting in a net reduction of the survival and/or reproduction of an actor to benefit a recipient) once perplexed biologists because it seemed paradoxical in a Darwinian world. More than half a century ago, W. D. Hamilton explained that when interacting individuals are genetically related, alleles for altruism can be favored by selection because they are carried by individuals more likely to interact with other individuals carrying the alleles for altruism than random individuals in the population (“kin selection”). In recent decades, a substantial number of supposedly alternative pathways to altruism have been published, leading to controversies surrounding explanations for the evolution of altruism. Here, we systematically review the 200 most impactful papers published on the evolution of altruism and identify 43 evolutionary models in which altruism evolves and where the authors attribute the evolution of altruism to a pathway other than kin selection and/or deny the role of relatedness. An analysis of these models reveals that in every case the life cycle assumptions entail local reproduction and local interactions, thereby leading to interacting individuals being genetically related. Thus, contrary to the authors’ claims, Hamilton’s relatedness drives the evolution to altruism in their models. The fact that several decades of investigating the evolution to altruism have resulted in the systematic and unwitting rediscovery of the same mechanism is testament to the fundamental importance of positive relatedness between actor and recipient for explaining the evolution of altruism.

Exit rights open complex pathways to cooperation

“…Nowak [18] divides these mechanisms into five categories-kin and group selection, as well as direct, indirect and network reciprocity. Others try to identify common principles behind all these mechanisms [19][20][21].…”

The role and rule of relatedness in altruism

“…Buff-tailed bumblebees (Bombus terrestris) are prime examples of biological altruism.The worker bees reduce their own reproduction to boost that of another individual, the queen (the large bee in the middle of the lower half of the image). Kay et al3 assessed papers proposing that altruism can evolve without relatedness, and conclude that the models presented are actually consistent with the long-standing idea 1 that interacting individuals must be related for altruism to evolve.…”

“…In fact, in the early 1960s, the evolutionary biologist W. D. Hamilton came up with a solution to this 'problem of altruism' with his inclusive fitness theory 1,2 , which shows that it is possible for altruism to evolve if socially interacting individuals are related. Writing in Proceedings of the National Academy of Sciences, Kay et al 3 conclude that multiple attempts to find alternatives to Hamilton's solution have simply rediscovered it.…”

“…Therefore, although previous findings need to be acknowledged, continued exploration of the theory is valuable. Lastly, the theory has nonetheless achieved notable successes, one of which is solving the problem of altruism 3,7,9 . A legitimate desire to tackle important, open problems should not prevent the field from recognizing this.…”

Genomic imprinting drives eusociality

“…The origin of eusociality poses a major challenge to Darwin’s theory of natural selection (Darwin, 1859) and it remains a subject of debate today (Kay et al, 2020; Nowak et al, 2010; Wilson and Hölldobler, 2005). Eusociality is an advanced state of sociality characterized by the presence of workers that forego personal reproduction in exchange for altruistic behavior toward close relatives.…”