Milax gagates (Draparnaud, 1801)
Fully mature adults of this species may be as long as 70 mm. The body of the animal may be grey-brown to black, gradually becoming lighter in color towards the foot. There are no obvious markings on the body of neither the adults nor juveniles. The mantle is large and may be slightly granular with a horseshoe-shaped groove in the center. There may also be 16-17 grooves between the keel and the pneumostome (breathing pore). The breathing pore is located in the posterior half of the mantle. There is a very prominent keel on the back of the animal, extending from the posterior edge of the mantle to the tip of the tail. The sole is tripartite: blackish with a pale median. There are "v"-shaped grooves along the median line of the sole. The mucus produced by this slug is clear.
Western Mediterranean, Western Europe and the Canary Islands
- U.S.: eastern North America, Pacific Northwest, California
Australasia: New Zealand, Australia
Asia: Japan, Sri Lanka
Europe: Britain, Mediterranean region
Milax gagates has been reported to be very destructive in Hawaii where it is decimating rare, native plants in Haleakala National Park (Hawaiian Islands). The keeled slug is known to cause yield reduction in soybean, sunflower and oilseed rape, by causing damage to seeds and seedlings. This pest species is capable of burrowing and often damages the roots and lower stems of plants (e.g., carrot, potato). The eggs are laid in tunnels made below the soil surface. Clutch size may be as few as 16. The incubation period for the eggs is approximately 25 days, juvenile mature within about 4-5 months.
- Limax gagtes Draparnaud, 1801. Tableau des mollusques terrestres et fluviatiles de la France: 100. Type locality? Montpellier.
- Limax maurus Quoy and Gaimard, 1824. Voyage L'Uranie et la Physic. Zool.: 427.
- Limax fulginosus Gould, 1852. U.S. Expl. Exped. XII: 5.
- Milax antipodarum Gray. 1855. Cat. Pulmonata Brit. Mus. 1: 177.
- Limax pectinatus Selenka, 1865. Mal. Blatt.: 105.
- Milax hewstoni Cooper, 1872. Proc. Acad. Nat. Sci. Philad.: 147.
- Milax emarginata Hutton, 1879. Trans. N.Z. Inst. 11: 331.
- Milax tasmanicus Tate, 1881. Pap. Proc. R. Soc. Tas.: 16.
- Milax nigricolus Tate, 1881. Pap. Proc. R. Soc. Tas.: 17.
- Amalia antipodarum var. pallida Cockerell, 1891. Ann. Mag. Nat. Hist. VII: 340.
- Amalia parryi Collinge, 1895. J. Malac. 4(1): 7.
- Amalia babori Collinge, 1897. Proc. Malac. Soc. Lond. 2(6): 294.
Anderson 2005; Barker 1979; Barker 1999; Clemente et al. 2010; Cowie et al. 2009; Kerney et al. 1979; Naggs et al. 2003