Altruistic Aussie bird isn’t

A puzzling example of altruism in nature has been debunked with researchers showing that purple-crowned fairy wrens are in reality cunningly planning for their own future when they assist in raising other birds’ young by balancing the amount of assistance they give with the benefits they expect to receive in the future.

Dr Anne Peters, of the Monash University School of Biological Sciences, together with co-authors Sjouke Kingma from the Max Planck Institute for Ornithology and Michelle L. Hall of the Australian National University, have conducted a long term study of the cooperative breeding behaviour of fairy-wrens in tropical Australia.

The results, published in the prestigious journal The American Naturalist, show that helpers are not motivated by kindness.

“The study showed that the seemingly selfless little helpers are in fact carefully calculating accountants” said Dr Peters, senior author of the study.

Cooperative breeding, where birds apparently selflessly raise others’ offspring, has long perplexed biologists as this behaviour runs counter to Darwin’s theory of natural selection, which predicts that individuals invest only in their own reproduction.

Fairy-wrens are habitual cooperative breeders. The helpers are generally older silblings or half-siblings of the current nestlings, and their behaviour is likely explained by an instinctive desire to see more of their shared genes entering the gene pool.

Purple-crowned fairy-wrens extend this assistance to unrelated nestlings.

Dr Peters’ study shows that these apparently altruistic helpers are actually playing a selfish game: they help when their chances of inheriting the current breeding territory are greater, and they are thus helping to raise their own future assistants.

“Ours is the first study to show that helpers at the nest adjust their behaviour precisely according to multiple potential rewards: they provide food to kin, and to unrelated nestlings to produce future helpers of their own,” Dr Peters said.

“However, we suspect once more researchers look at their study species in this dual light, more cases will be found of helpers that can do their sums so precisely.”

http://www.monash.edu.au

1 COMMENT

  1. This article is typical of “neodarwinist” fundamentalism. Everything that looks like altruism in nature must be really a selfish gene being cleverer than science has been able to figure out – until now. First, this attitude is not Darwin’s. Darwin defined fitness from the good of the community when it was appropriate. It was only the 20th century “neodarwinists” who claimed that EVERY adaptation must have short-term benefit for reproductive potential. Second, there remain many, many big examples of widespread phenomena in nature that cannot be explained by this paradigm: The separation of 2 sexes. Cellular senescence, and other forms of programmed aging. Hox genes. are three. Third, when you read the article carefully, the “precise calculation” turns out to be only a possible loophole, not a proof that this phenomenon evolved without the action of group selection.

    The whole story of neodarwinian fundamentalism and the denial of group selection is told in the book “Unto Others” by David Sloan Wilson and Eliot Sober. http://books.google.com/books?id=ouwg5swAV5oC

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