Laevicaulis alte is a round, dark-coloured slug with no shell, 7 or 8 cm (2.8 or 3.1 in) long. Its skin is slightly tuberculated. The central keel is beige in colour.
This slug has a unique, very narrow foot; juvenile specimens have a foot 1 mm (0.039 in) wide and adult specimens have a foot that is only 4 or 5 mm (0.16 or 0.20 in) wide.
The tentacles are small, 2 or 3 mm (0.079 or 0.118 in) long, and they are only rarely extended beyond the edge of the mantle.
The species is already established in the USA, and is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national quarantine significance in the USA.[9]
Habitat
Laevicaulis alte lives in dry areas, mostly at lower altitudes.[10]
Ventral view of foot of juvenile specimen
Life cycle
The slug hatches from eggs. Laevicaulis alte has several adaptations for living in dry conditions: a rounded shape with as small as possible surface area, and a narrow foot to reduce evaporation.
Juvenile specimens search for food nearly always at night, and stay buried in the soil during the day. Larger specimens are active during the day sometimes. The slug can grow up from 0.5 cm (0.20 in) to approximately 4 cm (1.6 in) in length in 7 months.[10]
^Rowson B., Warren B. H. & Ngereza C. F. (2010). "Terrestrial molluscs of Pemba Island, Zanzibar, Tanzania, and its status as an "oceanic" island". ZooKeys70: 1-39. doi:10.3897/zookeys.70.762
^Cowie R. H., Dillon R. T., Robinson D. G. & Smith J. W. (2009). "Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment". American Malacological Bulletin27: 113–132. PDFArchived 2016-06-16 at the Wayback Machine
