Behavioral Origin of Tremulation, and Possible Stridulation, in Green Lacewings (Neuroptera: Chrysopidae)

Abdominal vibration or "jerking" in connection with courtship behavior has been described for several green lacewing species (e.g. Smith 1922; Toschi 1965; Tauber 1969; Sheldon and MacLeod 1974) and explored in detail by Henry (1979, 1980a, b, c). In Chrysoperlo cornea (Stephens) isolated individuals produce long, patterned sequences of discrete short bursts of rhythmic vibration of the abdomen in the vertical plane. The wings may also vibrate. Sexually receptive pairs establish duets of reciprocal abdominal jerking. Actual drumming of the abdomen on the substrate does not occur. It had been assumed that abdominal vibration produces high-frequency sounds by stridulation (Adams 1962, Riek 1967, Eichele and Villiger 1974, Henry 1979) and acoustical communication was discussed in connection with the tympana1 ultrasound receptor organ described by Miller (1970, 1971). Courtship and copulation take place on the vegetation, usually on the underside of leaves. Henry (1980a, c) in his work with Chrysoperla spp. demonstrated that communication is performed via low-frequency substrate vibration and not by airborne sound. Males were able to establish duets with females within a range of 15 cm. According to Henry (1980a, b, c), differences in the vibration patterns of Chry-