Quantula striata

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.[2]

Quantula striata
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Order: Stylommatophora
Family: Dyakiidae
Genus: Quantula
Species:
Q. striata
Binomial name
Quantula striata
(Gray, 1834)
Synonyms[1]
  • Helix naninoides Benson, 1842
  • Hemiplecta leechi de Morgan, 1885
  • Nanina striata Gray, 1834

Distribution

This species occurs in Singapore, Malaysia,[3] Cambodia, the Philippines, Fiji, and some islands in the Rhio Archipelago.[4]

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.[5] The umbilicus is narrow.[6] The color of the shell is brown, shading to white underneath.[5]

Anatomy

The length of the body is up to 5–6 cm.[5] The dorsal part of the head and foot is dark brown in color.[5] The ventral parts are creamy white in color.[5] The eye tentacles are long, and the eye spots are large.[5]

Bioluminescence

Quantula striata is the only terrestrial gastropod known to exhibit bioluminescence.[7] This was not discovered until 1942, when it was reported by Dr. Yata Haneda (see also Haneda 1946),[8] probably because the flashes are quite dim.[5] The purpose of the snail's bioluminescence is not yet fully understood, but it is thought to have some relation to animal communication.[8] Light is emitted by an organ known as the "organ of Haneda,"[9] located in the head-foot region of the adult snail. This organ consists of a 0.5 mm-wide cluster of giant cells [4] and is a part of the suprapedal gland.[4] The snail flashes while it is moving, and half as intensely when it is feeding, and does not flash when it is inactive.[8] Flashes lasts 0.5–6.0 s.[8]

The light produced is yellow-green, with a wavelength of about 515 nm. The substance which produces it has not yet been identified.[4] Isobe at al. (1991)[4] 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.[5]

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.[9]

These snails feed on vegetation, fruit and vegetables, and also on the decaying flesh of already dead animals.[5][8]

In captivity the snails can feed on cucumber, lettuce, carrots, apple, and boiled eggs.[4][5][8] The snails can eat chalk for calcium, and commercially available rat food for protein.[5]

See also
  • Latia neritoides, a freshwater snail from New Zealand, is the only other pulmonate gastropod that shows bioluminescence.

References
  1. MolluscaBase eds. (2021). "Quantula". WoRMS. World Register of Marine Species. Retrieved 3 April 2021. {{cite web}}: |author= has generic name (help)
  2. Tumpeesuwan C., Naggs F. & Panha S. (31 August 2007) "A new genus and new species of dyakiid snail (Pulmonata: Dyakiidae) from the Phu Phan range, northeastern Thailand". Raffles Bulletin of Zoology 55(2) Archived July 22, 2009, at the Wayback Machine: 363-369. PDF
  3. Daston M. M. & Copeland J. (1993) "The luminescent organ and sexual maturity in Dyakia striata". Malacologia 35(1): 9-19. abstract
  4. Isobe M., Yuakul D., Sigurdsson J. B., Goto T. & Lam T. J. (1991) "Fluorescent Substance in the Luminous Land Snail, Dyakia striata". Agricultural and Biological Chemistry 55(8): 1947-1951. abstract and PDF.
  5. Counsilman, J. J.; Ong, P. P. (1988). "Responses of the luminescent land snailDyakia (Quantula) striata to natural and artificial lights". Journal of Ethology. 6: 1–8. doi:10.1007/BF02348856. S2CID 12203232.
  6. Asia and the Pacific Islands - The World of Snails Archived April 4, 2010, at the Wayback Machine
  7. Isobe, M.; Uyakul, D.; Goto, T.; Counsilman, J. J. (1988). "Dyakia bioluminescence—1. Bioluminescence and fluorescence spectra of the land snail,D. Striata". Journal of Bioluminescence and Chemiluminescence. 2 (2): 73–79. doi:10.1002/bio.1170020204. PMID 3213594.
  8. Copeland J.; Daston, M. M. (1989). "Bioluminescence in the terrestrial snail Quantula (Dyakia) striata". Malacologia. 30 (1–2): 317–324.
  9. "On Quantula striata (Gray, 1834) a bioluminescence snail with a compilation of related works". Online "Micro shells [ECOLOGY : Quantula striata (Gray,1834)]". Archived from the original on November 6, 2009. Retrieved November 24, 2009. Last change: 30 January 2007, accessed 27 November 2009.

Further reading
  • Copeland, J. (1988). "Optic nerve responses to light stimulation in the bioluminescent terrestrial snail, Dyakia (Quantula) striata". Comparative Biochemistry and Physiology A. 89 (3): 391–400. doi:10.1016/0300-9629(88)91046-8.
  • 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.
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