Abstract
Acoustic communication is widespread in beetles, is often sexually dimorphic, and plays a significant role in behaviours such as premating recognition, courtship, and copulation. However, the factors that determine the presence or absence of acoustic signalling in a given species remain unclear. We examined acoustic communication in bark beetles (Scolytinae) and pinhole borers (Platypodinae), which are two speciose groups with widespread sound production capabilities. We show that body size along with the sequence of host colonisation predict the presence of acoustic communication, and report, for the first time in the animal kingdom, a size limit-1.9 mm-below which acoustic signalling ceases to be present.