Phenomenon found in all human malarial parasites, that after a short phase of adaptation the growing of schizonts, the formation of merozoites, and the resulting rupture of the red blood cells occur at the same time in all infected red blood cells. It has been suggested the paroxysms of fever sharpen the level of synchronicity. Furthermore the host's circadian rhythm is also a determining factor. Altogether synchronicity represents an adaptation of the parasites to optimize the transmission by night-biting mosquitoes ( Anopheles spp.).