ABSTRACT
The Earth’s rotation on its own axis gives rise to daily changes in light and temperature, while the tilt of the Earth relative to its plane of rotation about the sun causes annual changes in light and temperature and, consequently, the changing of seasons. The length of day and its rate of change are functions of latitude; at higher latitudes, days are longer and day length increases more rapidly than in areas at lower latitudes after the spring equinox. Conversely, at higher latitudes, days are shorter and day length decreases more rapidly as compared to lower latitudes after the autumn equinox. Colder climates are typically associated with higher latitudes, which restrict the duration of seasons that are ideal for growth and reproduction even with longer days. Insects have responded to these geographic variations in climate by evolving appropriate modifi cations to their photoperiodism.
