Though most Martian tribes have instituted polygamy in order to perpetuate their tribes, which generally have a disproportionate amount of females to males (usually in the range of 12 to even 17 to one females per male), polygamist marriages are not without their challenges, especially in a society where females are taught to aggressively defend the males of the tribe. This tendency toward aggression can spill over into relations between companion wives who share a husband.
Generally, the husband is responsible for mediating and settling disputes between wives, but if the husband refuses or abdicates his responsibility then one wife may challenge another to a duel. To do this, she removed the earring symbolizing her marriage and hurls it to the ground at the feet of the challenged wife.
The challenged wife may accept the duel by picking up the earring. If she does not pick up the earring she must accede to the demands of the challenging wife.