Antlions are sensitive to subnanometer amplitude vibrations carried by sand substrates

European pit-building antlions (Myrmeleon inconspicuus / Rambur 1842) are studied in their capacity to detect vibrations generated by the locomotion of an ant (Cataglyphis cursor) outside the pit. These locomotions have been recorded by laser velocimetry and copied in detail in their time sequences. The sequences are replicated by micro-controllers digital outputs acting on piezoelectric transducers placed several centimeters outside the peripheries of the pits: their actions on the surface of a sand media create surface waves with particle accelerations that are 3 orders of magnitude less than g, alleviating any possibility of sand avalanche towards the bottom of the pit. Depending on the amplitude of the vibrations, the antlions answer back, generally by sand tossing. One remarkable feature is the time delay from the start of the cue and the aggressive behavior induced by this cue. This time delay is studied versus the cue amplitude. The result of this work is that anlions answer back within minutes to cues with amplitudes between 1 to 2 nanometers at the level of their mechanosensors, and within seconds to these same cues if they are preceded by a sequence of signals at the Ångström amplitude. This induced aggressive behaviour evidences the sensitivity to vibrations at extremely low level.