Amplitude plot (above) and spectrogram (below) of two prepupal tapping sounds of Hoplitis tridentata originating from two individuals inhabiting the same nest; the sounds were recorded with a batlogger in a distance of 20 cm from the opened nest stem.

 
 
  Part of: Müller A, Obrist MK (2021) Simultaneous percussion by the larvae of a stem-nesting solitary bee – a collaborative defence strategy against parasitoid wasps? Journal of Hymenoptera Research 81: 143-164. https://doi.org/10.3897/jhr.81.61067