Quantula striata, also known as Dyakia striata, is a species of medium-sized, air-breathing, tropical land snail. It is a terrestrial, pulmonate, gastropod mollusk in the family Dyakiidae. This species appears to be unique among terrestrial gastropods in that it is bioluminescent: its eggs glow in the dark, and juveniles and most adults give off flashes of green light.

It is the only species in the genus Quantula. This species occurs in Singapore, Malaysia, Cambodia, the Philippines, Fiji, and some islands in the Rhio Archipelago. Quantula striata is the only terrestrial gastropod known to exhibit bioluminescence. This was not discovered until 1942, when it was reported by Dr. Yata Haneda (see also Haneda 1946), probably because the flashes are quite dim.

The purpose of the snail’s bioluminescence is not yet fully understood, but it is thought to have some relation to animal communication. Light is emitted by an organ known as the “organ of Haneda,” located in the head-foot region of the adult snail. This organ consists of a 0.5 mm-wide cluster of giant cells and is a part of the suprapedal gland.

The snail flashes while it is moving, and half as intensely when it is feeding, and does not flash when it is inactive. The eggs of this species glow, and so do newly hatched snails. Juveniles can produce flashes of light, as can most, but not all, adults.

In Singapore these snails live in a variety of disturbed habitats, such as lawns, walkways and rubbish dumps, and like most land snails, they are observed more often after rain. These snails feed on vegetation, fruit and vegetables, and also on the decaying flesh of already dead animals.