The physiological state of the mosquito can modulate behaviours that are normally activated by external stimuli. Even though host stimuli may be present at certain times, the insect may not always express host-seeking behaviour, depending upon the physiological factors that predominate. Traditional views of the gonotrophic cycle characterize mosquitoes as engaging in blood feeding only once before depositing eggs. However, physiological state, including such factors as age, nutritional state, presence of eggs, mating condition, circadian rhythmicity and the number of gonotrophic cycles completed, can affect the expression of this behaviour.