Worm charming

Wurmgrunzen (am. Worm grunting ) is a method to drive earthworms by vibrations from the ground in order to be able to pick them up.

Procedure and dissemination

Methods to drive by means of vibrations worms to the soil surface, are widely used. The method is called Wurmgrunzen in the narrow sense, which is applied in the Southeastern United States for generations. In this case, the worm hunter drives a wooden stake into the ground and put him in vibration by rubbing with a metal rod on the upper end. The vibrations earthworms are initiated within up to twelve meters to flee from the soil to the surface.

The collected earthworms are even used by collectors as bait for fishing or sold to anglers. A few people even deny them their livelihood. In Sopchoppy in Northwest Florida is about an annual Worm Gruntin ' Festival. They exchanged experiences, buys Wurmgrunzer T-shirts and selects a Wurmgrunzer Queen. The Wurmgrunzen in neighboring Apalachicola National Forest was so popular in the 1960s and 1970s that the park administration feared for the survival of local earthworm Diplocardia mississipiensis and introduced a still existing authorization for the Wurmgrunzen within the park.

Similar methods, in conjunction with competitions such as the Great Canadian Worm Charming Championship and Festival and the Devon Worm Charming Festival, under the designations are Worm Charming and Worm Fiddling known in Canada and England. The vibrations are generated by means other than the Wurmgrunzen, and there are sometimes aids such waters used to acupuncture of the soil. From Germany reported methods that use in-ground plugged pitchforks, to generate appropriate vibrations.

Behavioral Explanation

Charles Darwin, the reports from all over Europe over the scarecrows out of worms had happened, suspected that the vibrations produced by the human hunters resemble those caused by moles digging. The behavior of the earthworms was designed to avoid the moles, their predators, under all circumstances. However, another popular theory maintained that the vibrations produced by people resembled the sound of falling rain drops, and the worms would flee from the ground, so as not to drown.

2008 Kenneth Catania was able to prove at Vanderbilt University, the correctness of the mole - hypothesis and falsify the raindrops hypothesis. Catania initially accompanied Wurmgrunzer at their collection activity and found a very high density of moles in the studied region. He also measured the frequency of the vibrations generated by the Wurmgrunzern and found that the frequency of 80-200 Hz corresponded to the noise, cause the Ostamerikanische moles when they tear up when digging with their powerful front blades grass roots. He took the grave sounds of moles on so sonicated the ground and was able to escape the same behavior of the earthworms produce as the Wurmgrunzer with its vibrant bars. In addition, he collected a large number of earthworms, put them in a planter box full of dust, then caught a mole and put it also in the planting box. When the mole is burrowing into the earth, began a mass exodus of earthworms to the surface.

Catania noted that a Ostamerikanischer mole per day almost eats its own body weight in earthworms; Thus, the mole is the most important predator of the worms by far.

The raindrops hypothesis, however, is implausible according to Catania. Although worms are also used in heavy rainfall in large numbers on the surface, but only when the soil is saturated after hours of rain water, and not. During the first minutes of a strong thunderstorm casting, in which the drum sound of raindrops is particularly pronounced

The escape behavior of the worms make next to the people and other predators advantage. For example, waddle herring gulls on the ground, to lure worms. The trampling of oystercatchers with both feet and the drums of lapwings with one foot on the meadow soil is often observed. Forest stream turtles stomp on the ground to achieve the same effect. Richard Dawkins called this phenomenon that prey through her geared towards the main predator behavior high risk of falling victim to other hunters, as the Rare Enemy effect.

Swell

• Catania, Kenneth: Mole - alarm à la Darwin. In: Scientific American. No. 2/ 11, 2011.
• Catania, Kenneth: Worm Charmers. In: Scientific American. March 2010.