Comparative stereo scanning studies on sense organs of some terrestrial spiders at Assiut, Egypt

Sensory organs reflect the effects of stimuli and reveal the biological events in their outside and inside environments. The behaviour of spiders is controlled by the central nervous system like in other animals. Spiders contain several types of sensory organs that help them recognize their surroundings. These sensory organs may have mechanoreceptor or chemoreceptor functions. All parts of the spider’s body contain different hairs, sensillae, setae and spines. The function of sensory structures is affected by their site in the spider’s body. This study aimed at describing different types, distribution and functions of sensory organs of five ground spiders inhabiting Assiut Governorate, Egypt. Fifty samples of spider specimens were collected by hand picking and pitfall traps during years 2016 and 2017 from different habitats. The specimens were examined under a binocular stereomicroscope and scanning electron microscope. The study revealed the presence of sensory organs on different body parts of the studied spiders, including sensilla trichodea, sensilla placodea, sensilla basiconica, sensilla styloconica, setae, trichobothria and slit sense organs (Lyriform organs). A significant difference in the position and type of sensory organs was detected between males and females of different spider species.