According to Queller (2006) kin selection is defined by how a "gene can produce copies of itself by increasing the fitness of its bearer (direct fitness) or by increasing the fitness of its relatives who share copies of the gene (indirect fitness)" (p.165). Kin selection favors increasing the fitness of relatives. Examples of this behavior follows.
Wolves live in tight family groups consisting of an unrelated breeding pair (dominant) and their offspring, sometimes including an unrelated subordinate individual. In addition to the dominant breeding pair, there are subordinate non-breeding adult individuals. Their pack structure is held together via complex social behavior. Why they behave this way is the answer to the relationship between kin selection and sexual selection.
Dominant wolves have fairly obvious benefits, especially in how they receive priority access to resources (including breeding). Subordinate wolves do not receive the same benefit, but instead provide allocare to the dominant's offspring. In return, they are protected by ample food, personal safety, and most importantly to this discussion: fitness through the success of their kin, aka the dominant's offspring.
Meanwhile, in order to attain dominant status within the wolf pack there is a high level of intrasexual competition, particularly between females of breeding age. These competitions are often extremely aggressive and very intense. Male wolves also do compete, but not to the same extent as females. Furthermore, males prefer highly dominant females. Competing females tend to have the capacity to fully perceive the social behavior or the subordinant females, ostracize them, and physically (if necessary) prevent them from breeding.
==Social Insects ==
A wide range of insects live together in groups and are highly social. While there is a variety, there is one key feature present in most of these groups: a division of labor (Queller & Strassmann, 1998). Most
prominent is the presence of a queen who is responsible for reproduction, as well as a large number of workers (Queller & Strassmann, 1998). A perfect example of altruism in social insects is the honeybee. The workers have a barbed stinger which detaches and eviscerates the worker when used (Queller & Strassmann, 1998). The sole reason for its sacrifice is the protection of the queen. The queen, on the other hand, has a barbless stinger utilized when competing for position with its sisters (Queller & Strassmann, 1998).
Another example of kin selection that I would like to have others comment on are the meerkats. One can say that meerkats fit the altruistic behaviors by one keeping watch while the others in the group look for food / eat. However, others argue that this is not an example of altruism because of the fact that the ones that keep watch have already eaten, and are not being selfless in this behavior. What do you think about the meerkats and altruism?
Santema & Clutten-Brock (2013) studied whether meerkat sentinal behavior was for the primary benefit of the sentinal, or for the group as a whole. Both applied, but was increased when pups were present. This pointed to cooperative behavior rather than pure altruism.
Jenks, S.M. (2011). A longitudinal study of the sociosexual dynamics in a captive family group of wolves: The University of Connecticut. Behav. Genet., 41, 810-829.
Queller, D. C., & Strassmann, J.E. (1998). Kin selection and social insects. BioScience, 48(3), 165-175.