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Study explores why some individuals sacrifice to help others reproduce

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10.03.2006

In a new study forthcoming in the April 2006 issue of The American Naturalist, Peter Nonacs (University of California – Los Angeles), Aviva E. Liebert (Tufts University) and Philip T. Starks (Tufts University) explore a theory of social behavior that seeks to explain why some individuals willingly sacrifice their own reproduction to help raise others’ offspring.

"Transactional Skew" (TS) theory proposes that such cooperation is possible through "shared reproduction," making it worthwhile to help close relatives because some of the same genes are getting passed along. Thus, the degree of shared reproduction should vary across groups by the degree to which they are related.

However, in a study across four species of paper wasps – long considered one of the best examples supporting this theory – the researchers found that not only was there cooperation and shared reproduction between sisters but also between distantly related or unrelated wasps.

"This result strongly rejects the unique TS prediction that the level of cooperation should vary across groups according to the attributes of individual group members," says Nonacs. "[We] propose an alternative explanation in which wasps seek to cooperate with close kin, but less related groups sometimes form due to recognition errors."

Suzanne Wu | Source: EurekAlert!
Further information: www.uchicago.edu

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