The Asian tiger mosquito (Aedes albopictus) is among the few species of mosquito for which a correlation between critical photoperiod—the day length that triggers half or more of a population to enter diapause at a certain point in autumn—and latitude and altitude has been established. A look at the body of research critical photoperiod in mosquitoes suggests more data on additional species could better align surveillance and management efforts with mosquitoes’ seasonally active periods. (Photo by Jim Occi, BugPics, Bugwood.org)