A story of sexual selection

Posted on March 22, 2011

8



A puzzle for those interested. Identify the alpha female:

When her status is questioned, the alpha female reasserts it by subduing her opponent physically. The alpha male objects to this, however, since this undermines his status as group leader. He, therefore, orders the beta male to punish the alpha female for her behaviour. Seeing a mating opportunity, the beta male decides not to punish the alpha female, which means that the alpha male punishes him, instead. Everyone engages in displays of fitness that involve the production of rhythmic sounds, showing their suitability for mating.

Having reasserted his authority, the alpha male looses interest in punishing the alpha female and seeks to mate with her, himself. The beta male decides to challenge the alpha male and, as a result, both he and the alpha female are forced to leave the lowland group and to join another group living in the mountains. A new male appears who displays his fitness by costly displays of conventionalised hunting behaviour, displacing the previous alpha male of the lowland group. The lekking males engage in a display of fitness that involves the production of rhythmic sounds.

In the mountains, the group that the beta male and the alpha female joined finds a secure location to rest and engage in social displays. A party led by two males leaves in order to scout out territory. The alpha female is disappointed by the beta male and wishes to find a new mate who will increase the fitness of her offspring. The new alpha male of the lowland group finds the group in the mountains and encourages them to see one of his costly displays, successfully attracting the attention of the alpha female. The beta male is drawn off by a former mate who tells him that one of his kin is in danger.

In a complex social display involving colourful plumage and rhythmic behaviour, the alpha female and the alpha male assert their authority over the lowland group. The beta male attacks and kills the alpha female who, due to the high cost of bearing young, is unwilling to decrease her fitness by mating with him. While neither her nor his genes will be passed on by them, the genetically determined behaviour they engaged in has in many cases been successful in leading to increased fitness, ensuring that the behaviour will be passed on and repeated in future generations. Everyone engages in the display of fitness involving the production of rhythmic sounds, showing their suitability for mating.

Advertisements