Figure 26.20 Life Cycle of the Malarial Parasite (A) Like many parasitic species, the apicomplexan Plasmodium falciparum has a complex life cycle, part of which is spent in mosquitoes of the genus Anopheles and part in humans. The sexual phase (gamete fusion) of this life cycle takes place in the insect, and the zygote is the only diploid stage. (B) Encysted Plasmodium zygotes (artificially colored blue) cover the stomach wall of a mosquito. Invasive sporozoites will hatch from the cysts and be transmitted to a human, in whom the parasite causes malaria.