Just the word “slug” makes people disgusted. A nasty, rather disgusting, shapeless, slippery creature immediately appears before your eyes, always crawling somewhere.
Doesn’t nature really have any intelligence that it could give birth to such an animal that no one needs and is not suitable for anything? To find the answer, you should study in more detail what characterizes the large roadside slug, the photo of which is now before your eyes. After reading the description of a slug, a person will have an idea of what the appearance of this creature is, what kind of life it leads, and where its habitats are located.
Large roadside (or leopard) slug: appearance
Representatives of this species are the largest of all types of large slugs. These mollusks were brought to different parts of the world from Europe, which is their homeland. The large roadside slug is a mollusk of the order Pulmonate snails. Its body consists of one leg that merges with the slug's head and is called the sole. The body length of the mollusk reaches from 10 to 20 cm. Sometimes the body of the animal grows up to 30 cm. It is wrinkled, somewhat rounded, and pointed at the end of the rear part.
The body of slugs is symmetrical on both sides. On top it is covered with the so-called mantle in the form of a plate. Below it are the reproductive organs and the anus. There is a keel on the tail.
The color of the slug ranges from light gray to chestnut, sometimes yellowish-white or ashen. The entire body of a large roadside slug is covered with black spots and stripes. This “cute” creature has very long tentacles. Their mucus is colorless.
Slugs on the site: why are they dangerous?
In the snail family, in the process of evolution, gastropods without shells appeared - slugs. Two species of herbivorous polyphages from the genus Limacidae and Arienidae pose a particular danger to agricultural crops.
The following types of slugs are common in the Limacidae family:
- reticulated grows up to 7 cm, has a gray or cream tint, a pointed end of the body;
- arable with a body length of up to 5 cm and a yellowish color;
- agile grows up to 2 cm, has a gray or brown tint.
In the family Arienidae, the most striking representative is the bordered slug. He lives in gardens and park areas. The mollusk grows up to 10 cm. Unlike representatives of Limacidae, it has a rounded body shape.
Internal structure
On the back, under the skin of the mollusk, a shell is visible, which, like all other slugs, is highly reduced. The shell is white in color, shaped like an oblong oval, its length is 13 mm and its width is 7 mm. It is assumed that healing substances are stored there. This shell has been known since ancient times and was used for medicinal purposes.
The leopard slug's digestive system consists of the radula, pharynx, esophagus and intestines. In the intestines, four sections are connected to the liver, while the other two simply hang freely inside the body.
At first glance, this slug resembles a very simple creature, but it has a nervous system that consists of ganglia. Each ganglion has its own place: the pedal ganglion lies under the radula, the abdominal ganglion is slightly to the right of the midline, and the visceral ganglia are located in the middle between the esophagus and the uvular membrane.
Habitats
The habitats of the large roadside slug cover large areas. The habitat is located in humid and temperate climate zones. Slugs live only in biotopes with sufficient moisture. For them, a very comfortable habitat is the litter of deciduous forests.
Slugs are indigenous to Australia, New Zealand and North America. They are also found in Western and Central Europe, in the Caucasus, where their favorite places are fields, meadows, forests, gardens and caves.
Large roadside slug: what to feed
These mollusks are herbivores and are not too picky when choosing food. While kept in the terrarium, they should be provided with vegetables, fruits and mushrooms. Separately, we need to dwell on what the large roadside slug feeds on in its natural habitats.
Vegetation is considered the main food of mollusks. The leopard slug feeds on fallen leaves, flowers, fruits and soft stems of living plants. Sometimes mushrooms are present in his diet. Although these slugs eat a lot and are voracious, if necessary, they can live without food for about 60 days, while in a humid place.
Large roadside slug: reproduction
This species, like all slugs, has a hermaphroditic reproductive system. Each individual has genitals that correspond to their sex. Reproductive products become mature at different times. First, the sperm matures. She presents packaged bags - spermatophores. Then the secretion of mucus begins in males. This substance is endowed with a smell by which the slug is found by its relatives.
The mating ceremony of large roadside slugs occurs in a very unusual way. The mollusks hang head down on mucous threads, their bodies are woven into a single ball by their genitals. Since the blue penises of slugs reach great lengths, it is not always possible for mating couples to disentangle themselves. In this case, some individuals resort to extreme measures and bite off the genital organ, which grows back after some time.
After fertilization, the mollusk lays eggs in the ground; on average, one adult can lay from 30 to 70 large eggs. Their development occurs within 21–35 days, after which small slugs are born. They reach sexual maturity after 60 days. These animals live no longer than two years.
Features of reproduction, or where the cubs come from
Of course, if there are adult slugs, then there must be “babies”. And this is so, and newborn individuals, or rather eggs, become a delicacy for many birds, insects and mammals. But let's first figure out how slugs reproduce.
There is no need to talk about males and males here, because gastropods are hermaphrodites. In other words, they have both male and female genital organs, and during mating they can act in any role. Surprisingly, in the animal environment it is these inconspicuous creatures that are recognized as “sexual giants”! The fact is that the length of their male penis is several times greater than the length of their entire body! For example, a banana slug grows on average to 15 cm, but its erect penis reaches 81 cm! This is a real record that no one else can boast of.
Reproduction of slugs is a mysterious and incomprehensible process. When mating, adults seem to envelop each other with their genitals. Often it is almost impossible to untangle such a “tangle,” so animals simply have to bite off the partner’s organ or their own. However, it does not always grow back, and the victim in the future can only use the remaining female part of the reproductive system. It is in this context that we can talk about the slug girl.
After the described process, fertilized eggs mature in the body of the participants. Then the adult lays them in moist soil. On average, there are about 50 eggs in one clutch; they mature in about a month, and the young are born. A newborn slug is no different from an adult, except perhaps in size. This is a tiny copy of the gastropod mollusk familiar to us all. After 2 months, the babies fully grow and become sexually mature, beginning to actively reproduce.
Economic importance. Damage caused
For nature, slugs bring some benefit, being orderlies. They are able to process leaves that have fallen from trees, turning them into humus. But most of all, these mollusks, including the large roadside slug, cause quite significant damage to agriculture.
These voracious creatures cause especially great harm to potatoes by eating the tubers and foliage of the plant. Cauliflower and white cabbage, various varieties of lettuce, root vegetables, young vegetable plants, as well as strawberries, tomatoes and cucumbers suffer from slug invasion. Vineyards and entire citrus plantations are affected by this pest.
The large roadside slug causes much less damage to the following crops:
- Red cabbage.
- Parsley roots and leaves.
- Onion and garlic.
- Crops of barley and oats.
Spring wheat, flax and buckwheat almost do not feel the invasion of slugs. In addition to the fact that mollusks voraciously destroy agricultural crops, they are also carriers of fungal and viral diseases. Among these pests is the large roadside slug. The description of these diseases, which include cabbage spot, potato late blight and downy mildew, makes it possible to once again verify the harmfulness of the slug. In this regard, the question arises: how can you get rid of such a nasty enemy?
Meet the Spanish slug
The “monster” is officially called the red slug (Arion lusitanicus) - also known as the Spanish slug, also known as the Lusitanian slug, or Portuguese slug.
If the usual garden slugs grow to 1.5-3 cm in length, then this giant can grow as much as 10-15 cm, although it is usually limited to 7-10 cm - which, however, looks no less terrifying for an unaccustomed gardener. Focusing on the species name will not always be correct - depending on the habitat, this slug can be either really bright red or red with a slightly darker head and “horns”, or a more inconspicuous gray-brown or cream (but never spotted) .
Some brightly colored specimens of the Spanish slug can be confused with the more common species, the red roadside slug (Arion rufus), which is equally large and “harmful.”
The Lusitanian slug is native to southwestern Europe (mainly the Iberian Peninsula), where it usually lives in gardens, fields or forested areas near human habitation. And it was from there that recently they began to accidentally import it into our latitudes along with soil, plants in pots, vegetables and fruits. Moreover, the Spanish slug attacks not only the countryside - the invasion of gastropod giants in the last couple of years has been noted even in such large cities as Moscow, Novosibirsk, Lvov, St. Petersburg, Riga, Tallinn... Mollusks settle in parks, cemeteries, along roadsides , crawl into playgrounds and landscaped green courtyard areas. And for summer residents this is a real disaster - red slugs are sometimes even collected in buckets from cultivated beds!
The Spanish slug is included in the list of the most dangerous invasive animal species for Europe (imported from other habitats). This pest, like a “regular” slug, is very voracious and absolutely unpretentious in its choice of food - it eats everything that small slugs do, only in much larger volumes in accordance with its size. And not only does it eat - by crawling from one plant to another, slugs contribute to the spread of various fungal and viral diseases among crops, which can cause losses to the farm no less, and often greater, than the direct harmful activities of slugs. And the giant slug has no natural enemies in our latitudes - no hedgehogs or jackdaws would be tempted by such a large creature.
In addition, the red slug reproduces very quickly in the same way (it is a hermaphrodite, so it does not need a partner for reproduction), producing several generations during the summer season (a single adult can produce up to 400 eggs in one warm and humid summer) and “leaving” for the next season of laying eggs, which are perfectly capable of overwintering in the depths of the soil - therefore, pest control in early spring and late summer is most relevant.
In addition, the Spanish slug truly threatens the health of people and animals. In addition to the fact that its mucus can be dangerous (poisonous), the mollusk is often an intermediate host for a number of parasitic worms, which as adults parasitize domestic and wild mammals and birds.
At one time, scientists hoped that the southern newcomer would not survive our harsh winters, however, as practice has shown, the mollusk has successfully adapted to a colder climate and now poses a real threat to plants.
Methods and methods of dealing with slugs
Before you find out what effective methods of controlling slugs exist, you need to study and use all available preventive measures in a timely manner. First of all, you need to ensure that the areas have a large number of natural enemies of slugs. These include hedgehogs, frogs and toads.
In addition, you need to make a trench around the area and sprinkle it with sand, pine needles, lime and crushed egg shells. The slugs will be forced to avoid such an obstacle. Plants in the beds should be kept weed-free and thinned out on time.
You can fight slugs by collecting them with your hands. To do this, at night, pieces of wet bark or piles of mown grass are laid out between the plants, under which the pest will hide. In the morning, the collection of a pest called the “big roadside slug” begins calmly by hand. People know many ways to get rid of it, one of them is catching shellfish with a can of beer, which in this case serves as bait for slippery uninvited guests.
If the above methods fail to get rid of slugs and mass reproduction of pests has already occurred, you will have to use chemicals. Currently, a new generation of products has appeared that do not pose any danger to the environment.
Agrotechnical method of control
The biological characteristics of slugs and their way of life are such that for normal existence they need damp, shady places where they can hide at any time. To repel pests, it is necessary to thin out and remove weeds in areas with crops. Remaining vegetation should be removed immediately to prevent rotting, which will facilitate the development of slugs.
In addition, it is necessary to remove boards, branches or stones from the areas, which provide an ideal hiding place for slugs. If they are widespread in the garden or garden, you need to remove the garden composter, which is an ideal place for pests to live and lay eggs.
Experts also recommend digging up and compacting the soil - this work should be done in warm, sunny weather. In this simple way, adult slugs are destroyed, and young individuals and eggs, once on the surface of the soil, dry out.
Interesting Facts
Do you know which animal on the planet ranks first among the toothy ones? This is probably very interesting to every person. Although surprisingly, the toothiest creature that is not a predator is the large roadside slug. There are approximately 30 thousand teeth on his tongue! This grater tongue helps the slug grind all the foods it feeds on and make large holes in them.
We can conclude that among the toothy individuals there are not only large predators, but also mollusks, which are among the smallest representatives of the animal world.
