Kin Recognition
Emperor Penguins, Photo Courtesy of WikiMedia Commons
The realization that many animal species can tell the difference between kin and non-kin added a novel aspect to the study of social behavior in animals. Kin recognition plays an important role in the social organization of species (Toth et al., 2009). Not only can some animals differentiate between relatives and nonrelatives, but they also act differently depending on their relatedness (Fletcher & Michener, 1987). The ability to recognize kin can serve different functions including kin selection and mate selection.
William D. Hamilton initiated the study of kin recognition in 1964 at the University of Oxford. Hamilton presents the theory that fitness is determined both by the survival and propagation of the individual’s genes and also by the survival and propagation of the individual’s relative’s genes (1964). At the time, this was a profound idea since most people believed that natural selection simply favored individuals that produced the greatest number of offspring. Hamilton brought natural selection down to the genetic level (Hamilton, 1964). He proposed that evolution makes no distinction between genes that are transmitted through offspring and copies of genes transmitted through indirect decedents, such as siblings and cousins. According to his kin selection theory, animals can increase their fitness both by producing young and by increasing the ability of their relatives to reproduce (Hamilton, 1964). An animals overall fitness, as measured by the total number of copies of their genes that are passed along, is called inclusive fitness. Through cooperative behaviors with kin, animals can increase the survival and reproduction rates of their relatives, which will indirectly increase their own inclusive fitness.
In order to act cooperatively, specifically with kin, animals evolved mechanisms to differentiate kin from non-kin (Hepper, 1991). Throughout the animal kingdom there are numerous variations on techniques that allow animals to discriminate kin depending on the function the kin recognition serves and the species specific behaviors (refer to Charpentier et al., 2007; Keller & Ross, 1998; Mateo, 2006; Pfennig et al., 1993; Schibler et al., 2007; Toth et al., 2009). Kin recognition mechanisms include spatial distribution, familiarity, phenotype-matching, and recognition alleles. Two primary functions of kin recognition are kin selection and mate preference.
This website was created in partial fulfillment of the requirements for Biology 323, Animal Behavior, at Davidson College in the Spring Semester 2009.
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