Irradiated automobile exhaust fumes and their components were tested as an attractant for the lovebug, Plecia nearctica Hardy. Of the five different aldehydes tested, formaldehyde and heptaldehyde were the two most attractive. Formaldehyde is the abundant aldehyde in the fumes of diesel exhaust and is probably the single most important attractant. A generalized description is given of the female antennae. Three different types of sensillum (spine) match the 1-2-wavelength criteria for an open-resonator dielectric antenna, as given by Kiely. A nonlinear IR spectrum obtained by blowing saturated formaldehyde air through a punch-hole scatter antenna is given. The 10.93-, 22.73-, 26.88-, 32.79-, and 42.19-µm maserlike lines match the predicted wavelength resonant modes for the three sensilla. This is considered direct evidence for a man-generated wavelength mimic of a natural attractant and also direct evidence of the validity of Callahan’s dielectric waveguide-nonlinear molecular (maserlike) emission theory of the insect communication system.
Philip S. Callahan, Thelma C. Carlysle, and Harold A. Denmark, "Mechanism of attraction of the lovebug, Plecia nearctica, to southern highways: further evidence for the IR-dielectric waveguide theory of insect olfaction," Appl. Opt. 24, 1088-1093 (1985)