Slug Mucus Reproduction And Life Cycle Predation And Defense

Like snails, slugs have two pairs of 'feelers' or tentacles on their head. The upper pair--optical tentacles--are light sensors; the lower pair provides the sense of smell. Both pairs are retractable and can be regrown if lost. On top of the slug, behind the head, is the saddle-shaped mantle, and under this are the genital opening and anus. The mantle also has a hole, the pneumostome, for respiration. The slug moves by rythmic muscular action of its foot

Most slugs eat leaves, fungus, and decaying vegetable material, but some are predators and most also eat carrion including dead of their own kind. Slugs eat using a radulaRadula is the scientific name for the toothed chitinous ribbon in the mouth of gastropods. They use it to graze and scrape off diatoms and other microscopic algae off rock surfaces and other substrata. The radula is common to all mollusks, except the biva, a rough, tongue-like organ with many tiny tooth-like denticles.

1 Mucus

Slugs produce two types of mucusMucus is a slippery secretion of the lining of various membranes in the body ( mucous membranes). Mucus aids in the protection of the lungs by trapping foreign particles that enter the nose during normal breathing. Additionally, it prevents tissues from d: one which is thin and watery, and another which is thick and sticky. Both are hygroscopicA hygroscopic or hydroscopic substance is a substance that absorbs water readily from its surroundings. An example is biodiesel, which absorbs water to about 1200 parts per million (PPM). Other hygroscopic substances include ethyl alcohol, methanol, conce. The thin mucus is spread out from the centre of the foot to the edges,the thick mucus spreads out from front to back. Mucus is very important to slugs as it helps them move around, and contains fibers which prevent the slug from sliding down vertical surfaces. Mucus also provides protection against predators and helps retain moisture. Some species use slime cords to lower themselves on the ground.

2 Reproduction and life cycle

Slugs are hermaphroditic: having both female and male reproductive organs. Once a slug has located a mate they encircle each other and sperm is exchanged through their protruding genitalia. A few days later hundreds of eggs are laid in holes in the ground. Although some species hibernate over the winter in temporate climates, in most species the adults die in the autumn.

3 Predation and defense

FrogA frog is a fresh-water amphibian which changes from a tadpole and is of the family Ranidae in the Order Anura. They are closely related to toads. The Ranidae are sometimes called the "true frogs" since a few members of other families also have common nams, toadAnsonia Atelopus Bufo Capensibufo Crepidophryne Dendrophryniscus Didynamipus Frostius Laurentophryne Leptophryne Melanophryniscus Mertensophryne Nectophryne Nectophrynoides Nimbaphrynoides Oreophrynella Osornophryne Pedostibes Pelophryne Peltophryne Pseuds, hedgehogFor the anti-submarine weapon see Hedgehog (weapon); for the mathematical concepts see hedgehog (curve) and hedgehog (metric). Atelerix Erinaceus Hemiechinus Mesechinus A hedgehog is any of a wide variety of small quilled mammals of the order Insectivoras, and some birds and beetles are natural slug predators.

Slugs, when attacked, can contract their body, making themselves harder and more compact and thus more difficult for many animals to get a hold. The unpleasant taste of the mucus is also a deterrent.

4 Slugs as pests

Some slugs are notable garden pests and there are various methods of controlling them. Commercial slug pellets containing metaldehyde or methiocarb are available, but are not approved for organic gardeningOrganic gardening is gardening, without using man-made chemical pesticides or chemical fertilizers. It is said by some of its supporters to be more in harmony with nature. Organic gardeners emphasise the importance of "feeding the soil, not the plant". as they can poison creatures further up the food chain. Aluminum sulphate can also be used and its proponents say that it is less toxic to the environment. Salt will cause a slug to dry out, but this is probably cruel to the slug and also washes away easily.

Slugs have an aversion to copper. Copper pipe can be used and commercial slug rings are available. A six inch (15 cm) length of plastic pipe with copper foil tape stuck round it can be used to protect individual plants. Slugs also find rough surfaces such as crushed eggshells irritating.

Beer traps can be used to drown slugs. Put a jar containing half an inch of beer (12 mm) into a hole in the ground. The slugs will be attracted to the beer and will drown. Comfrey can be used as a decoy. Put comfrey leaves round plants that need protecting. The slugs will eat the comfrey and leave the protected plant alone. (This is the honeypot approach.)

Encouraging natural predators will help to keep the slug population under control.

Nematodes are parasites that can be used to kill slugs.

Finally, night time patrols can be useful.

For best results, several methods can be used together.

5 See also

6 External links

Slug biology
Slugs - snails without shells a fairly comprehensive web site.

Molluscs

<Hide>

Home > Slug