The lugworm  (Arenicola marina)

also (sandy) Pierwurm, belongs to the class of bristles at the root of many annelids. Through his life in the sands of Watts it is characteristic of the ecology of the mudflats in the east of the Atlantic Ocean. In the wider public he is one of the best known animals of Watts, in particular, what is his seemingly omnipresent characteristic droppings in the mud.

Features
The reddish-brown worm is about 20 to 40 cm long and is in the front half as thick as a finger. The rear end is thinner. In principle, there is only the intestine. All other organs (reproductive, etc.) and also the external gills are located in the front section. Lugworm weigh about 40-50 grams

Spread
The lugworm Arenicola marina is in the mudflats of the eastern Atlantic region, especially in the Wadden Sea, North Sea, common. In the Wadden Sea of ​​the western Atlantic (North America), he is represented by the type Arenicola cristata. He is one of the few species that prefers the total watts of the low-to colonize the high water line, but unstable sandy tidal flats.
 

Lifestyle and nutrition
The larvae of Wattwurms are moving on the surface of the ground, of if there are fewer predators in the autumn than summer. Up to six millimeters in size, they settle in horizontal tubes just under the surface in areas of silt watts and spend the winter there. Next July, they dig vertical tubes just below the high water line and spend time there until the autumn.

Before the winter, the animals then drag in the area of distribution of adult animals. There, the adult animal digs his 20-30 cm deep tubes in U-form in the Wadden Sea. He constantly eats the sand of Wattes and filters out there the organic substances, which he then exploited. Still, it remains mobile and contributes to the destabilisation and revolution of watt floor. The Sandworms in the North Sea to eat the entire sand of Wattes of 20 cm depth annually. The fact contributes to this, that the animals in a density of about 40 copies per square meter occur. A single Lugworm filters 25 kg sand per year.

About every 30 to 40 minutes comes the Lugworm at the exit of his tube and will launch the ingested sand, marked the output range of its tube as spaghetti shaped piles (worm poop). The entrance is marked with a hole on the surface, which can be seen during low tide as a small depression in the Wadden Sea. This area is called "Feeding Hopper". There, he takes up the nutrient-rich sand to exploit him. Coarse particles are not eaten, but are deposited at the head. There is a layer of coarser material in 20 to 25 cm depth.

Reproduction
The Lugworm is reach sexual maturity after two years. During the full moon of the month of October, he plants on himself by the male makes his sperm into the water. When the sperm reaches the living tube of a female, this gives off the eggs into the water. It retains the fertilized eggs as long in its tube until they are hatched. Then the young in the free water swim. They settle to the hibernation in the fine substrate, only in the following year they can drive on the sand plates, the Habitat of the adult Sandworms.

Predators
The birds such as the Oystercatcher, the Red Knot and Dunlin of watt areas adapted to life in mud run at low tide. Their long legs and their long pointed beaks are characteristic for this species. As soon as a new worm poop out of the ground kringelt, poking around the birds with their beaks into the tube and try to grab the worm. To avoid, that he is completely eaten, the Lugworm can repel his thin back end piecemeal. The bird gets to eat only one or two centimeters and it can save in the depths of its tube.

http://de.Wikipedia.org/wiki/Wattwurm