Unselfish behavior has evolutionary reasons

Altruistic behavior is seen as a human characteristic. There are many examples of altruistic behavior in the animal kingdom. In a new study, researchers at the University of Bern show that animals that help others to raise their young have an evolutionary advantage.

Altruism is when you do something that benefits someone else at a cost to yourself. The rearing of the next generation is one of the most amazing examples of selflessness in the animal kingdom. Some mammals, birds, and insects can be found in Lake Tanganyika. The other members of the group help in raising the young when there is a single dominant breeding pair. The members of the group are acting altruistically by taking care of young that are not their own.

This type of care makes sense when the young are siblings of the caregivers and the brood care helpers are able to give down the genes that make up the care via their siblings. It doesn't make sense to look after young people with whom you aren't related. So why do unrelated group members help? The Institute for Ecology and Evolution at the University of Bern is collaborating with the University of Los Andes and the University of Neuchtel on a new study.

Benefits of genetic fitness are important.

Natural selection favors the improvement of genetic fitness. Individuals with better survival chances benefit from a higher reproductive success throughout their life. This is shown in our study using computer simulations. The researchers were able to compare their success rates with the results of the simulation of the decisions of the group members.

The study shows two ways in which natural selection causes group members to help with caring for the young of dominant breeders. One possibility is if the young are related to the siblings of the caregivers. kin selection is a mechanism in which the genes shared between helpers and receivers of help are spread to the next generation.

The second way involves individual selection, which is not contingent on relatedness levels. The social group expands when more young animals survive. This increases the survival chances of the caregivers because they are less likely to fall victim to a predator. They will be able to breed successfully later on. The selection mechanisms interact with each other.

The environmental conditions affect which mechanism prevails.

The environmental context determines which of the two selection mechanisms comes into play. Kin selection is more important for cooperative care if the environment is favorable. If the environment is less favorable, then raising the number of group members is a more important selection mechanism that causes non-parental offspring care.

Whether an animal does better by remaining in its territory and raising the offspring of others in the group, or rather by moving elsewhere to attempt independent reproduction, varies with an individual's age. Natural selection favors animals to leave their territory earlier or later.

The study found that the relative importance of kin selection and individual selection varies depending on the environment, and that both the age of the animals and the ecological conditions significantly influence the selection of morals and altruism.

More information: Irene García-Ruiz et al, The evolution of cooperative breeding by direct and indirect fitness effects, Science Advances (2022). DOI: 10.1126/sciadv.abl7853 Journal information: Science Advances Citation: Unselfish behavior has evolutionary reasons (2022, May 30) retrieved 30 May 2022 from https://phys.org/news/2022-05-unselfish-behavior-evolutionary.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.