At long last, answers to the truly important ecological questions of the age. Namely: How can one tiny little mosquito bite a person so many times during the night?
The simplest explanation is that the victim tossed and turned, interrupting the feeding before the mosquito had its fill. The mosquito has a sensory nerve that signals the brain when the midgut is full; otherwise feeding would continue until the bursting point.
It is also possible that some blood types are not as easily thinned by the anticoagulant in the mosquito’s saliva, so the mosquito has to make more tries to get a satisfying meal. Another factor may be the mosquito’s search for an accessible vein near the skin surface, much like that of a nurse trying multiple sites to take a blood sample.
Some studies suggest that multiple feeding attempts occur more often when the mosquito is either acquiring or transmitting a disease organism, like the malaria parasite, because of a chemical feedback system between mosquito and prey. It has even been suggested that some mosquitoes can transmit chemicals that make the host less sensitive to inflammation after a series of bites, so that more blood can be taken.