What type of movement are the flowers of Crocus and Tulip highly sensitive to?

The flowers of Crocus and Tulip are highly sensitive to thermonasty, which is a type of variation movement that is induced by changes in temperature. These flowers open on the rise of temperature and close when the temperature is lowered. 

Thermonasty is a common phenomenon in plants and is used to regulate the temperature of the flower, protect the reproductive structures from temperature stress, and optimize pollination. 

Nyctinasty and thigmonasty or seismonasty are movements induced by changes in light and touch, respectively.