Vibratory Alarm Signals in Two Sympatric Higher Termite Species: Pseudacanthotermes spiniger and P. militaris (Termitidae, Macrotermitinae)

When they are disturbed, soldiers of the two termite species Pseudacanthotermes spiniger and P. militaris hit the substratum with their head, thereby producing sounds. High-speed video recordings allowed us to analyze the movement. The sound emissions were recorded and their temporal structure was analyzed. Artificial stimulation proved that head-banging acts as an alarm signal transmitted through the vibrations produced in the substratum. Perception of these vibrations induced a polyethic response. Workers reacted to head-banging by escaping. Minor soldiers reacted by escaping, becoming immobile, or head-banging, thereby indicating the existence of positive feedback in signal production. Differences in the time patterns of the drumming appeared between both species but could not be shown to play a role in species recognition.