What are the three ways characters commit suicide in My Antonia? Why do you think Cather includes these examples?

Part of the power of Cather’s novel is her acknowledgement that the immigrant experience could be a harsh one. Mr Shimerda’s suicide is an example. Antonia’s father is profoundly unhappy in Nebraska—he cannot speak the language, his position as head of household is usurped by his wife, his skill as a musician, a source of much prestige in Bohemia, is unvalued. Ultimately, he takes his own life, shooting himself with a shotgun.
The other death is Wick Cutter’s murder/ suicide. Cutter shoots his wife through the heart while she is sleeping, then mortally wounds himself in he neck. His plan is to foil any plan his wife might have to gain control of his money; he purposely wounds himself in a way that will allow him to explain to those who find him that since he has survived his wife, any will she might have made was null and void.
Both shootings are essentially caused by greed. Mr Shimerda finds that he has sacrificed his self respect to his wife’s greed and determination to accumulate land and good marriages for her children. Cutter’s actions are motivated by his determination to keep control of his own money. Far from romanticizing the immigrant experience, Cather shows in these two episodes how grasping after money can lead to tragedy.