INTRODUCED LAND SNAILS OF THE FIJI ISLANDS

Sarasinula plebeia (Fischer, 1868) Current Risk Status in Fiji: Medium to High FAMILY (=VAGINULIDAE)

Body Type: , no shell

Size: Description & Distribution Adults up to 5 cm in length Description USP Introduced Land plebeia (Fischer, 1868) Snails of the Fiji is a relatively large shell-less Islands Fact Sheet slug. The upper surface (notum) Series, No. 4 is leathery and can sometimes ap- pear pitted. The body form is flat- tened and becomes more elon- gate when the is alive and crawling. The notum colour is generally light to dark mottled brown with no pale stripe. Like all members of its family a mantle cavity is absent. The pneumo- stome (breathing pore) is very Source and location of photographs: small (Shea 2006) and located at G. Brodie (Viti Levu) & P. Ryan the posterior, under the notum. The head has two pairs of tenta- cles; the upper pair have terminal eyes. The tentacles are hidden Distribution under the notum when the slug is is native to Cen- inactive. Because of its surface tral America however it is now Direct funding from the Critical widely distributed throughout the Ecosystem Partnership Fund texture, mottled brown colour and (CEPF) and a USP FSTE Grant is elongated oval shape, S. plebeia Americas and the Pacific. According gratefully acknowledged. is sometimes referred to by the to Barker et al. (2005) this is common name “Caribbean widely distributed across the Fiji Leatherleaf”. Islands. Special points of interest: • Veronicellid are notori- Habitat & Behaviour ously hard to identify . Fiji’s S. plebeia is most readily con- fused with Semperula wal- Habitat Behaviour lacei. Sarasinula plebeia is generally Sarasinula plebeia is nocturnal, hid- found in moist leaf litter or or- ing during the day. According to • With breeding in the wet sea- son S. plebeia can reach high ganic material on the ground, or Rueda et al. (2002) the species is population densities in dis- under stones or rotting logs in ar- most active between 2 to 4 am and turbed habitats. eas relatively close to human individuals can travel up to eleven habitation. It is also found to be metres in a single night. It has also • S. plebeia is an important arboreal on low vegetation. In Fiji, been recorded that these slugs can agricultural pest. It is ranked in the top 10 mollusc species S. plebeia is found in low to mid- bury themselves to depths of 25cm with potential to have major land disturbed forests, planta- to 1 metre during the dry season pest significance for the tions, grass lands and gardens (Garcia et al. 2007). United States. (Barker et al. 2005). Page 2 Sarasinula plebeia (Fischer, 1868)

FIJI LAND SNAILS P. Ryan Biology

Sarasinula plebeia is an hermaphrodite i.e. indi- to water and diet quality. Reproduction is gener- viduals are able to function as both male and fe- ally high during the rainy season with maturity male during their lifetime. If kept in isolation, reached at ~ 2.5 months (Garcia et al. 2007). self-fertilization may occur (Rueda et al 2002). Populations in Mexico are known to increase sub- The species lays eggs (oviparous) and produces stantially during heavy continuous rain and this 1 - 4 clutches per year that average ~ 30 eggs. phenomenon has also been observed in Fiji. The species regulates its food intake in response Threats & Similar Species Threats diate host for the related nematode, A. costaricen- Sarasinula plebeia is an agricultural pest on nu- sis, which causes an inflammatory disease of the merous crops and can be extremely abundant intestine in humans (Rueda et al. 2002). (Cowie et al. 2009). The species is a polyphagous Similar Species herbivore (feeds on a variety of plants) but pre- Two other introduced veronicellid slugs occur in fers young leaf tissues and soft stems. S. plebeia Fiji. S . plebeia is most similar to Semperula wal- is the most important pest of bean crops in Cen- lacei, but the latter is smaller, generally paler tral America. It is also a known pest in several brown and with an indistinct pale stripe running overseas countries for sweet potatoes, cucurbits longitudinally over the mantle (S. Gomez pers. and nursery mahogany (Rueda et al. 2002, Garcia comm.). alte is larger and darker, with et al. 2007, USDA 2010). a pale stripe running longitudinally over the man- S. plebeia is a possible vector in Fiji for parasites tle. These slugs are very variable in body colour- like the rat lung worm Angiostrongylus cantonen- ation however they are readily distinguished by sis, which can cause meningoencephalitis in hu- their internal anatomy, especially that of the re- mans. The species is also known as an interme- productive system (Gomes & Thomé 2001). Further Reading

Barker, G.M., Price, R. & Briggs, C. (2005). Priorities for ad- Soleolifera) ocorrentes nas regiões Australiana e Oriental. ditions to the Fijian protected natural areas network: an Biociéncias 9: 137-151. assessment based on complementarity in land snail as- Rueda A., Caballero R., Kaminsky R. & Andrews K. L. (2002). semblages. New Zealand Landcare Research contract re- Vaginulidae in Central America, with emphasis on the port prepared for Wildlife Conservation Society, Suva. bean slug Sarasinula plebeia (Fischer). In: Barker G.M. 162 pp. (ed.). Molluscs as Crop Pests. CABI Publishing, New York. Bishop, M.J. (1977). Terrestrial of Queensland: the Rueda A. A., Slansky F. & Wheeler G.S. (1991). Compensa- family Veronicellidae. Memoirs of the Queensland Museum tory feeding response of the slug Sarasinula plebeia to 18: 53 – 59 pl. 18. dietary dilution. Oecologia 88: 181-188. Cowie, R.H., Dillon, R.T. Jr., Robinson, D.G. & Smith, J.W. Shea, M. (2006). Exotic snails and slugs found in . (2009). Alien non-marine snails and slugs of priority quar- Malacological Society of Australasia Newsletter 130: 7-8. antine importance in the United States: A preliminary risk Thomé J. W. (1975). Os gêneros da familia Veronicellidae assessment. American Malacological Bulletin 27: 13-132. nas Américas (Mollusca; ). Iheringia Zoologia Garcia, E.N. Thome, W.J., & Casteillejo,J.A. (2007). Review 48: 3-56. of Veronicellidae from Mexico (Gastropoda: Soleoliferea). USDA (2010). New Pest Response Guidelines-Tropical Ter- Revisita Mexicana de Biodiversida 78: 41-50. restrial Gastropods. United States Department of Agricul- Gomes, S.R. & Thomé, J.W. (2001). Anatomia comparada de ture, Washington D.C. 29 pp. cinco espécies da família Veronicellidae (Gastropoda,

How to Cite: For Further Information Contact: Brodie, G. & Barker, G.M. 2012. Sarasinula plebeia Dr Gilianne Brodie, Biology Division, USP, (Fischer, 1868). Family Veronicellidae. 'USP Introduced Suva, Fiji Islands. Phone: 679 3232876, Land Snails of the Fiji Islands Fact Sheet Series’, No. 4. Email: [email protected]