In wild turkeys, male turkeys that are related to eachother will band together to form groups where only one male in the group will reproduce and the others will simply exist to help the dominant male. It was shown that this is a form of "cooperative evolution" in which the genes of the nonreproducing males live on through the dominant male. The results were shown to be consistent with Hamilton's rule.
Could suicide be an evolved trait? In the case of Turkeys, the choice to be sub-dominant (and to never reproduce) is always done within families. Similarly, if suicide was evolved for in a similar way, it might be that there's a "family" trigger. For example, if a "subdomininant male" believes that his family's fitness would be higher without him (maybe in a poor family where lack of food will produce two males with studented growth), suicide might be more likely as it increases the "dominant males" potential reproductive success. But if that male is an only child and there are no cousins or potential for other kin - suicide would hurt the genetic fitness of the family.
Is there any evidence of this?