Altruism Evolved from Manipulation, Study
Here's a new finding that'll make you think a little less of humanity. A new study revealed that kindness might have evolved from manipulation.
Scientists believe that manipulation could be responsible for the evolutionary origins of some helpful or altruistic behavior.
Manipulation occurs when an individual or the "manipulator" changes the behavior of another individual in ways that is beneficial to the manipulator but may be detrimental to the manipulated individual. Manipulation occurs in humans, animals and even at the cellular level. It is seen among cells in a multicellular organism, or in parasites, which can alter the behavior of their hosts.
Researchers bring up the case of the parasitic roundworm Myrmeconema neotropicum. Once the roundworm is ingested by the tropical ant Cephalotes atratus, the parasite causes the ant to grow a bright red abdomen that mimics berries. The ants' red bellies then make them a target for birds that eat berries. After the birds eat the "berries" or infected ants, the parasite can then spread through bird droppings, which are subsequently collected by foraging Cephalotes atratus and fed to their larva.
Researchers in the latest study developed a mathematical model for the evolution of manipulated behavior and applied it to maternal manipulation in eusocial organisms, such as ants, wasps, and bees, which form colonies with reproductive queens and sterile workers.
In the model, mothers give birth to two broods. They manipulate the first-brood offspring to stay in the maternal site and help raise the second brood. Mothers can do this by messing up the offspring's development through poor feeding or aggressive behavior. The manipulated offspring of the first-brood will stay and help raise the second brood. However, first-offspring can resist manipulation and leave.
In the model, researchers show that an offspring's resistance to manipulation may often fail to evolve, if the costs of resistance are high. Therefore, this helping or altruistic behavior was coerced through manipulation.
"The evidence in so-called primitive eusociality, where helping is often coerced through aggression or differential feeding, appears consistent with these results," lead author Mauricio Gonzalez-Forero said in a news release.
The study is published in the journal The American Naturalist.