Eusocial Behavior

Social behavior: Behavior that relates to interactions with other members of the population. Pros/cons of group living. <Society> a group of individuals of the same species that is organized in a cooperative manner extending beyond sexual and parental care.

Group Living, altruism, coorperative behaviors may emerge if genes for such characteristics are favored. This may occur under different circumstances

1. Egoistic solutions: selfish herd; Mutualism although the behaviour may seem altruistic, individuals benefit directly (e.g. living in a group and co-operating with others directly benefits the individual because of the general advantages of group living).
2. Reciprocal altruism where the benefits accrued to the individual exceed the costs it incurs
3. Kin selection when behavior sufficiently enhances the fitness of related individuals (i.e., carrying similar genes) leading to an increased representation of genes being passed on to the next generation

Eusociality: an extreme form of altruism where sterile workers labor on behalf of reproductive individuals, cooperation in the care of young. There must be an overlap of at least two generations of individuals which share in colony labor.

Inclusive Fitness: refers to the sum of an individual's <Direct Fitness> (probability of reproductive success of one's own offspring) and its <Indirect Fitness> (probability of reproductive success of non-descendant relatives). Altruistic acts are frequently directed towards relatives. <Kin Selection>: selection for traits that lower an individual's personal fitness, but raise a relative's fitness. Recipient (related) kin share genes with the altruistic individual and are thus genetic extensions of them. Kin selection and inclusive fitness can explain sociality through increased survivorship of relatives, increased inclusive fitness, altruism, and delayed maturation or breeding.

Hamilton's Rule

benefit to recipient / cost to altruist > 1 / coefficient of relatedness