Thrips can survive the winter as adults or through egg or pupal diapause. Longer days may prompt pupae to develop early, while shorter days result in pupal diapause. In the temperate regions, the winters are passed in a pupal diapause stage. Insects undergo a type of dormancy to survive these conditions, called diapause. The larval stage is followed by a period of diapause or hibernation in a pupa. Some species can overwinter as adults in diapause. In cooler climates, the larvae may diapause over winter. At high temperatures and long photoperiods, fewer larva enter diapause. It is the later instars which experience multiple annual periods of diapause. This is an example of facultative embryonic diapause. Two types of mammalian embryonic diapause have been identified. In insects that undergo obligate diapause, termination may occur spontaneously, without any external stimuli. Results show that secretory neurons are necessary for entering the reproductive diapause. This allows them to blend in with their surroundings during vulnerable times like diapause (hibernation). Eggs can go into a quiet dormant phase or diapause.