Magnetic orientation of spider webs of the Amaurobiidae spiders

Abstract First of all in theoretical part of my bachelor thesis I deal with general characteristics of spiders and more specifically Amaurobiidae spiders. My first section summarizes information about magnetoreception as an ability to sense the Earth´s magnetic field. Next I describe basic information about three theories that represent models of functioning magnetoreception. Electromagnetic induction theory is based on the principle of an electric circuit through which flows electricity. Chemical magnetoreception theory or free radical theory is based on complex biochemical reactions which are produced by magnetic field and includes pairs of free radicals as intermediates. And the last but not least magnetite theory that presume presence of magnetite in various tissue which acts as a magnet, and at the moment of trying to compare with magnetic field applying pressure to the secondary receptors or directly affects the activity of nerve cells. Further I describe various forms of magnetic orientation for example magnetic compass, magnetic alignment and magnetic map. The end of the theoretical part is about the general knowledge of magnetoreception and magnetic orientation in Amaurobiidae spiders. The practical part is about my own research. I examined magnetic orientation of particular spider webs at 3 locations. I tried to find varied locations in different forest stands and slopes. My data collection was more difficult because of meteorological conditions. Long sweltering summer completely dried forests and all animals activity was inhibited. Then it came dramatic cooling and large amounts of rainfalls. In 2015 wasn´t basically a kind of transition phase between summer and autumn. Finally I gathered all data that I needed, and from the statistical processing clearly concluded that the resulting vectors were most commonly ranged from 100° to 180°. More than 60% spider webs were oriented southeast to south. Of course I founded exceptions and curious cases