The answer is macrophages. They either actively invade these leukocytes or are phagocytosed, divide in the cells and cause lysis. The promastigotes that invade these leucocytes are transformed into amastigotes in the macrophages. These amastigotes continue attacking other healthy macrophages while others migrate to the mid gut.
Predators have to eat. If things are good in an eco-system then the prey is eating good which means the predators can eat good also. Starvation means that things in the eco-system are going bad. Also, It helps the earth maintain its balance. If too much of any aspect of the system is removed it throws the whole thing off balance. too many herbivores will eat too much vegetation.
