Slit sense organs and kinesthetic orientation

Abstract

In the hunting spider Cupiennius salei Keys, kinesthetic orientation towards a catching site from which it has previously been chased away is observed. This ability strongly depends on the lyriform slit sense organs found on femur and tibia of the walking legs. The animals miss the original catching site, if these organs are destroyed on all legs. The mean angular deviation of the starting angles of the returns increases significantly as compared with intact spiders (P<0.005). Also, the directions of the mean vectors of the starting angles change (P<0.05).