Final answer:
During the erythrocytic stage of the malarial life cycle, merozoites infect red blood cells and reproduce asexually, but sexual reproduction to produce microgametocytes and macrogametocytes does not happen in this stage; it occurs in the mosquito's gut.
Step-by-step explanation:
The question asks which event does not happen during the erythrocytic stage of the malarial life cycle. To answer this, we need to examine the life cycle stages of the malaria-causing parasite, Plasmodium. During the erythrocytic stage, merozoites infect red blood cells (erythrocytes) and reproduce asexually through a process called schizogony, leading to the rupture of the infected cells and the release of additional merozoites. This cycle causes the characteristic symptoms of malaria.
Option 1 is incorrect as sporozoites are not produced within erythrocytes. Instead, sporozoites are the forms of the parasite that are injected by the mosquito into the host and then develop in the liver, not within erythrocytes. Options 2 and 4 correctly describe the processes during the erythrocytic stage, with parasites being protected from the host's immune system while inside the red blood cells, and merozoites being reproduced asexually.
Option 3, concerning the sexual reproduction of the parasite to produce microgametocytes and macrogametocytes, does not occur during the erythrocytic stage but rather happens in the mosquito's gut after a mosquito has taken a blood meal from an infected host. Therefore, option 3 is the correct answer to the question as it is the event that does not occur during the erythrocytic stage of the malarial life cycle.