Olfactory perception and inclusive fitness

Abstract

Within an established colony, sexually mature male rats interact with little or no conflict, but unfamiliar males are readily attacked and subjected to’ prolonged and physiologically deteriorating social stress. Evidence is offered in support of the ontogeny, stimulus characteristics, and adaptive significance of this social discrimination. It is asserted (1) that two odor categories are implicated in the determination of identity, (2) that dominant males are exposed to individual odors of juveniles prior to their attainment of a postpubertal androgen based odor, and (3) that such exposure is the basis for subsequent immunity from attack. Sequence of odor development in young males, therefore, reveals the biological mechanism that governs the selective display of territorial aggression. Males maturing within the confines of an established territory, and likely to be the offspring of the alpha or his siblings, thus gain a higher probability of reaching reproductive maturity and eventual alpha status. This epigenetic phenomenon confers selective advantage and promotes inclusive fitness.