A behavior largely overlooked outside humans -- grandparenting -- has now been observed in birds, according to a molecular ecologist.
David Richardson, University of East Anglia in England, and his colleagues have for more than 10 years investigated the Seychelles warbler (Acrocephalus sechellensis) -- once one of the world's rarest birds -- and seen for the first how senior birds that no longer breed often help their children rear their young.
This helps the grandparents protect their genetic legacy, Richardson suggested.
Suitable territory for breeding on the islands is limited, so older adults typically stop breeding there. The researchers discovered that roughly two-thirds of such older female Seychelles warblers helped their daughters raise offspring by incubating eggs or feeding nestlings.
"Because the subordinate females are helping to raise offspring they are related to, they are helping to produce more birds and increasing the spread of their genes," Richardson said. "This has never been seen in birds."
The researchers now want to look into why some females keep breeding and why others seem to lose their breeding rights only to become grandparent helpers.
"Are they being pushed out or are they moving out to allow their daughters to breed? We don't know whether they are getting pushed out by their male partner or their daughter," Richardson said. These findings could shed light on the conditions required for grandparenting behavior to evolve.
"By having a different system to compare and contrast to the human system, we may better understand what factors drive the evolution of each system," Richardson told LiveScience.
Source:Xinhua/Agencies
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