FACT: There are more than 160 mosquito species in North America alone, and different mosquito species exhibit different behaviors. They prefer different kinds of hosts. Some feed just before nightfall, others around the clock or whenever a host is near. So adult spraying has to be intelligently timed to reach mosquitoes when they're flying, and when the wind, humidity and general climate conditions favor target species. In Minnesota, there are 50 mosquito species.