The Evolution of Manipulation: Altruism Created by Manipulated Behavior

Manipulating a person may be seen as morally repugnant, but new research has shown that it might not be all bad. Scientists have discovered that manipulation may be responsible for the evolutionary origins of some helpful or altruistic behavior.

Manipulation occurs when an individual alters the behavior of another in a way that may be beneficial to the manipulator, but may be detrimental to the manipulated individual. This particular phenomenon doesn't only occur in humans, though.  It also occurs in animals and even at the cellular level, such as among cells in a multicellular organism or in parasites that can alter the behavior of their hosts.

For example, the parasitic roundworm Myrmeconema neotropicum can alter the behaviors of the tropical ant Cephalotes atratus, which lives in Central and South America. When the ant ingests the worm, it grows a bright red abdomen; this mimics the appearance of berries. Birds are, in turn, attracted to these bright red ants and eat them, spreading the parasite in their droppings. More ants are then infected by these droppings and the cycle begins again.

In order to examine manipulation, the researchers developed a mathematical model for the evolution of manipulated behavior. Then then applied it to maternal manipulation in eusocial organisms, such as ants, wasps and bees, which form colonies with reproductive queens and sterile workers. In this model, mothers produced two broods; they manipulate the first-brood offspring to stay in the maternal site and help raise the second brood. They accomplish this by disrupting their offspring's development (for example, poor feeding or aggressive behavior). The alternative is that first-brood offspring resist this manipulation and leave.

"The evidence in so-called primitive eusociality, where helping is often coerced through aggression or differential feeding, appears consistent with these results," said Mauricio Gonzalez-Forero, who conducted the study, in a news release.

The findings reveal that individuals can be coerced into helpful behavior through manipulation. This, in turn, shows that altruistic behavior may have its basis in manipulative practices, revealing a little more about evolution.

The findings are published in the journal American Naturalist.