Nepotism is also found in fish interactions

A cichlid fish of the species Neolamprologus pulcher.
© Arpan | iStock

Family members of dominant couples benefit from special privileges. A study in Bern has shown for the first time that this favouritism allows some fish to be lazier than others.

Scientists from the University of Bern set out to investigate whether fish from cooperative species favour their relatives. They confirmed that the group leaders punished their family members less severely if they failed to do their chores. For example, while in general they physically attack – or even exclude from the school all together – fish that fail to look after their eggs, this aggression is reduced if the offender is one of their own descendants. Such nepotism reduces their social control in favour of preserving their genes. “This general principle most likely plays an important role in many animal societies, including humans,” observes Irene García-Ruiz, first author of the SNSF-funded study (*) published in the journal iScience.