Acoustic component and social context of the wing display of the walnut fly Rhagoletis juglandis

Courtship signaling via wing vibration, accompanied by sound production, ha s been reported in several species of tephritids. In this large family of f lies, sound communication as well as complex courtship displays appears to be restricted to species with lekking mating systems (i.e., Mediterranean f ruit fly, Anastrepha and Dacus species). In contrast, in tephritid species with resource-defense mating systems, such as species in the genus Rhagolet is, little or no courtship behavior acoustical or otherwise, has been descr ibed Wing displays in Rhagoletis species have been considered to play a vis ual role. This study describes a distinctive wing display per-formed by mal es of the walnut fly, Rhagoletis juglandis. Laboratory experiments and fiel d observations demonstrate that the male wing display plays a role in court ship. We used sound and vibration detectors to record the signals produced by this wing display Using a combination of techniques, we were able to rec ord both the very low-frequency vibration and its accompanying airborne inf rasound (12-22 Hz) produced by the males.