American researchers search for clues to the mysterious disappearance of American silk moth with an experimental field study on unintended consequences of biological insect control succeeded American researchers, are the cause for the extinction of numerous species of butterflies on the track. Startled by the mysterious decline of the American silk moth (Cecropia moth), North America, with a wingspan of up to 15 cm largest moth type George Boettner, wildlife biologist at the University of Massachusetts at Amherst and his colleagues took a parasitic European species of fly (Compsilura concinnata) in the sights. She had been suspended in an extensive program started in 1906 by scientists and the U.S. Government, in addition to 80 other parasitic and predatory insects to combat the gypsy moth infestation rampant in the United States. Inadvertently the 4-to 5-inch gypsy moth moths (Lymantria dispar) were reached between 1868 and 1869 to North America.
With one Propagation speed of 10 to 15 km per year spread they complete forests in Massachusetts until the middle of the 20th century over the entire United States, entlaubten in a short time and became one of the most important pests in forestry and fruit growing. With the predatory Compsilura fly, one wanted to establish an effective opponent of the dangerous forest pests. The advanced parasite sink using a Legebohrapparates their eggs in the larvae of many species of butterflies and about 180 other species of insects are attacking. Until 1986, they were exposed in 30 U.S. States. But parallel to spread the previously frequent SilkWorm, as well as many other species of butterflies disappeared. To get a possible link to the track, the workgroup by George Boettner 300 silkworm caterpillars bred and each suspended five per tree in different sections of the Cadwell Memorial Forest in Massachusetts.
After a week, they gathered them and let continue to grow them in the laboratory. Rather than to turn into magnificent moths died in 81 percent of the caterpillars eaten by countless Compsilura fly maggots. The repetition of the experiment with a different type of moth resulted in loss rates between 52% and 100%. These experiments are the proof that the pest control used insects can threaten native species”, says Donald Strong, an ecologist from the University of California in Davis. In the United States began a discussion about tightening the safety operations of non-native parasitic insects to fight insect pests. Too late for the silkworm and others pursued by the investigations on tachinidae from butterflies. You find yourself in the face of additional hazards of pesticides and Habitat loss in increasing numbers on the red list. Ulrich Karlowski