Competition, loss of selfishness mark shift to supersociety

Jun 11, 2007

How social or altruistic behavior evolved has been a central and hotly debated question, particularly by those researchers engaged in the study of social insect societies – ants, bees and wasps. In these groups, this question of what drives altruism also becomes critical to further understanding of how ancestral or primitive social organizations (with hierarchies and dominance fights, and poorly developed division of labor) evolve to become the more highly sophisticated networks found in some eusocial insect collectives termed “superorganisms.”

In a paper published online May 21 before print by the Proceedings of the National Academy of Sciences (PNAS), a pair of researchers from Cornell University and Arizona State University propose a model, based on tug-of-war theory, that may explain the selection pressures that mark the evolutionary transition from primitive society to superorganism and which may bring some order to the conflicted thinking about the roles of individual, kin, and group selection that underlie the formation of such advanced eusocial groups.

A superorganism ultimately emerges as a result of intergroup competition according to findings by theoretician H. Kern Reeve of Cornell University’s Department of Neurobiology and Behavior and professor Bert Hölldobler of Arizona State University’s School of Life Sciences and Center for Social Dynamics and Complexity.

Reeve and Hölldobler’s model is unique in that it is comprised of two interlocked nested tug-of-war theories. The first piece describes the tug of war over resource shares within a group or colony (intragroup competition), and the second piece incorporates the effects of a tug-of-war between competing colonies (intergroup competition).

According to Hölldobler, the path to colonial supergiant is first paved by the maximization of the inclusive fitness of each individual of the society. How this might arise, he believes, is that competition that might exist between individuals in the same society diminishes as the incipient colonial society becomes larger, better organized and contains better division of labor and ultimately, cohesiveness.

“Such societies in turn produce more reproductive offspring each year than neighboring societies that are less organized. Thus, genes or alleles that code for such behaviors will be propagated faster,” Hölldobler says.

The second piece of the model takes into account that “as the colonial organization of one group rises, there is a coincident rise in discrimination against members of other societies of the same species.” Hölldobler notes that the competition between societies soon becomes a major force reinforcing the evolutionary process: “In this way the society or insect colony becomes the extended phenotype of the collective genome of the society.”

Hölldobler believes that this model developed with Reeve goes further than others in explaining the evolutionary transition from hierarchical organizations to superorganism, “as it also demonstrates how the target of selection shifts from the individual and kin to group selection.”

Such a nested tug-of-war model, he says, might also be applied “equally well to the analysis of the evolution of other animal societies” and give insight into the evolution of cooperation in non-human and human primates, in addition to such things as collectives of cells and the formation of bacterial films.

Source: Arizona State University

Explore further: Top Japan lab dismisses ground-breaking stem cell study

add to favorites email to friend print save as pdf

Related Stories

New challenges for ocean acidification research

Dec 19, 2014

Over the past decade, ocean acidification has received growing recognition not only in the scientific area. Decision-makers, stakeholders, and the general public are becoming increasingly aware of "the other carbon dioxide ...

Warming world may spell bad news for honey bees

Nov 25, 2014

Researchers have found that the spread of an exotic honey bee parasite -now found worldwide - is linked not only to its superior competitive ability, but also to climate, according to a new study published ...

Recommended for you

Scientists target mess from Christmas tree needles

9 hours ago

The presents are unwrapped. The children's shrieks of delight are just a memory. Now it's time for another Yuletide tradition: cleaning up the needles that are falling off your Christmas tree.

Top Japan lab dismisses ground-breaking stem cell study

17 hours ago

Japan's top research institute on Friday hammered the final nail in the coffin of what was once billed as a ground-breaking stem cell study, dismissing it as flawed and saying the work could have been fabricated.

Research sheds light on what causes cells to divide

Dec 24, 2014

When a rapidly-growing cell divides into two smaller cells, what triggers the split? Is it the size the growing cell eventually reaches? Or is the real trigger the time period over which the cell keeps growing ...

Locking mechanism found for 'scissors' that cut DNA

Dec 24, 2014

Researchers at Johns Hopkins have discovered what keeps an enzyme from becoming overzealous in its clipping of DNA. Since controlled clipping is required for the production of specialized immune system proteins, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.