Quantula striata
Encyclopedia
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.
, Malaysia, Cambodia, the Philippines
, Fiji
, and some islands in the Rhio Archipelago.
. 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. Flashes lasts 0.5–6.0 s.
The light produced is yellow-green, with a wavelength
of about 515 nm
. The substance which produces it had not yet been identified. Isobe at al. (1991) stated that the fluorescent substance "may be similar to flavin
".
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.
These snails feed on vegetation, fruit and vegetables, and also on the decaying flesh of already dead animals.
In captivity the snails can feed on cucumber, lettuce, carrots, apple, and boiled eggs. The snails can eat chalk for calcium, and commercially available rat food for protein.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of medium-sized, air-breathing, tropical land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
. It is a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
, pulmonate, gastropod mollusk in the family Dyakiidae
Dyakiidae
Dyakiidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Dyakioidea ....
. 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.
Distribution
This species occurs in SingaporeSingapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
, Malaysia, Cambodia, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, and some islands in the Rhio Archipelago.
Shell description
The shell of this species is dextral (right-handed) in coiling. The shell of an adult snail is 16–27 mm in width. The umbilicus is narrow. The color of the shell is brown, shading to white underneath.Anatomy
The length of the body is up to 5–6 cm. The dorsal part of the head and foot is dark brown in color. The ventral parts are creamy white in color. The eye tentacles are long, and the eye spots are large.Bioluminescence
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 communicationAnimal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
. 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
Suprapedal gland
The suprapedal gland or mucous pedal gland is an anatomical feature found in some snails and slugs. It is a gland located inside the front end of the foot of gastropods.The term suprapedal means "above the foot"....
. The snail flashes while it is moving, and half as intensely when it is feeding, and does not flash when it is inactive. Flashes lasts 0.5–6.0 s.
The light produced is yellow-green, with a wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
of about 515 nm
Nanometre
A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...
. The substance which produces it had not yet been identified. Isobe at al. (1991) stated that the fluorescent substance "may be similar to flavin
Flavin mononucleotide
Flavin mononucleotide , or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin by the enzyme riboflavin kinase and functions as prosthetic group of various oxidoreductases including NADH dehydrogenase as well as cofactor in biological blue-light photo receptors...
".
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.
Ecology
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.
In captivity the snails can feed on cucumber, lettuce, carrots, apple, and boiled eggs. The snails can eat chalk for calcium, and commercially available rat food for protein.
See also
- Latia neritoidesLatia neritoidesLatia neritoides is a species of small freshwater snail or limpet, an aquatic gastropod mollusc in the family Latiidae.The type specimen is in the British Museum.The specific epithet "neritoides" means "like a nerite"...
, a freshwater snail from New Zealand, is the only other pulmonate gastropod that shows bioluminescence.
Further reading
- Copeland J. (1988) "Optic nerve responses to light stimulation in the bioluminescent terrestrial snail, Dyakia (Quantula) striata". Comparative Biochemistry and Physiology Part A: Physiology 89(3) 391-400.
- Copeland J. & Counsilman J. J. (1986) "Neuroethological Studies of Behavior in the Land Snail Dyakia (Quantula) Striata". International Society for Neuroethology Abstracts 1: 93.
- Copeland J., Counsilman J. J., Loh D., Chan S. Y., Tan W. H. & Maneri M. (1987) "Factors Affecting the Rate of Flashing and Loss of Luminescence in an Asian Land Snail Dyakia Striata". Veliger 29: 394-439.
- Haneda Y. (1946) "A luminous land snail, Dyakia striata, found in Malaya. Seibutsu 1: 294-298.
External links
- Photo of the live snail
- Photo of another live snail
- Image of the shell
- Four views of one shell
- More shell images
- Quantula striata at National Center for Biotechnology InformationNational Center for Biotechnology InformationThe National Center for Biotechnology Information is part of the United States National Library of Medicine , a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper...
(NCBI)
