Answer

It is permissible to kill such animals and insects which are harmful to ones self. However, to make the animal suffer is haram.

According to the teachings of Islam, causing pain and suffering to defenceless and innocent creatures is not justifiable under nay circumstances.

Saaiduna Abu Huraurah Radiallahu Anhu reports that the Prophet of Allah Sallallahu Alahi Wasalam forbade making animals suffer. (Sahih Bukhari)