Slug

Slug name for any of the air breathing terrestrial gastropod mollusks of the order Stylommatophora that either lack a shell or have a tiny, rudimentary, or reduced internal shell. Slugs are all hermaphroditic usually with reversed torsion, and mantle cavity moving back along right side and ultimately lost. They have a distinct head which bears two pairs of retractile tentacles with eyes located on the tips of the longer posterior pair. Slugs show a circadian rhythm or activity and generally become active at night, feed on plants, and hide themselves in soil burrows or under straw residues, litter, bricks or hips of pebbles and other waste residues at day time. They are generally important as agricultural and horticultural pests in the temperate regions and in some subtropical countries also. They prefer cold and moist environment for their proper propagation.

Slugs are pests of a range of crops and horticultural plants world wide, but in Western Europe potato and wheat are at the greatest risk. Girasia burtii (Ariphantidae), Incillaria monticola (Philomycidae), Indosuccinea semiserica (Succinidae), Semperula birminica (Veronicellidae) and Doris (Doridae) are among the slug species recorded from Bangladesh. G. burtii and I. monticola feed on the tender leaves of various green grasses and shrubs growing on the slope of the hills in the Sylhet and Maulvibazar areas. I. semiserica are abundantly present in the eastern belt, viz Noakhali, Comilla, Chittagong and Sylhet. S. birmanica are distributed throughout the country. They devour both the roots and aerial portion of the plants with their rasp-like radula. [Md Sarwar Jahan]