Evasive behaviour in the cave‐cricket, Troglophilus cavicola

Abstract

ABSTRACT. Cave crickets of the genus Troglophilus occur in caves of the Alps and Dinarides generally in wintertime. Most hibernation sites in caves were inclined at more than 60° to the horizontal. The crickets show a striking escape behaviour which is strongly influenced by the inclination of the surface on which they are standing: stimulated adequately, they readily jump from horizontal surfaces, but only rarely from the side walls or roofs of caves. An arena with a tiltable floor was used to quantify this and other behavioural effects in relation to the degree of inclination of the floor, and gave the following results, (a) From 0° to 60° the rate of evasive jumping was inversely related to the steepness of the floor; above 60° jumping was almost completely inhibited. (b) Below 75° more than half the crickets showed a positive thigmotaxis to the arena walls, above 75° this thigmotaxis was much weaker, (c) The effect of blinding was to reduce these levels of thigmotaxis at inclinations lower than 60° and to increase the thigmotactic response at steeper inclinations, (d) Standing orientation was generally upwards at inclinations steeper than 60°; below 45°, the steeper the floor, the greater this upward orientation tendency, (e) If the cricket was standing orientated downwards, evasive jumping was less inhibited on slopes between 15° and 60°.