Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2007
Publication Date: 6/1/2008
Citation: Mankin, R.W., Lemon, M., Harmer, A.M., Evans, C.S., Taylor, P.W. 2008. Time-pattern and frequency analyses of sounds produced by irradiated and untreated male Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) during mating behavior. Annals of the Entomological Society of America. 101:664-674. Interpretive Summary: Sterile male releases are an important means of controlling pest fruit flies, but concerns have been expressed that sterilizing radiation renders mass-reared insects less sexually active than wild rivals. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology and at Macquarie University analyzed sounds produced by irradiated and nonirradiated Queensland fruit flies to assess the effects of irradiation on the quality of flies released in sterile-insect-release programs. Although the wingbeat frequencies were similar, the time patterns of calling and courtship sounds differed significantly between irradiated and untreated males. Such differences have the potential to affect mating competitiveness. The results of these analyses are discussed in relation to comparable studies of Mediterranean fruit fly and other sound-producing tephritids.
Technical Abstract: Behavior and sounds associated with mating of mass-reared irradiated and untreated (non-irradiated) Bactrocera tryoni (Froggatt) males were analyzed using synchronous acoustic and video recordings. The flies tested were from a population used in sterile release programs that help maintain fruit-fly-free areas in Australia. Male fruit flies typically produce three distinct types of sounds in different contexts, 'calling', 'courtship', and 'copula' sounds, as mating progresses. 'Calling' sounds are wing-vibration pulse trains of variable, relatively long duration that most often occur before the male orients toward the female. 'Courtship' sounds are rapid trains of relatively constant duration that occur after the male has oriented toward the female. 'Copula' sounds are produced after mounting. Although the frequencies were similar, the temporal characteristics of calling and courtship sounds differed significantly between irradiated and untreated males. Such differences have the potential to affect mating competitiveness, but no differences were observed in the proportion of irradiated and untreated males that copulated in the laboratory. It was determined also that the wingbeat frequencies of flight, calling, courtship, and copula sounds are significantly correlated within individual flies, possibly because all these vibrations are produced by the same flight motor, with the amplitude of vibration affected by the positioning of the wings relative to "stops" on the thorax. Wingbeat frequency was not correlated with wing area. The results of these analyses are discussed in relation to comparable studies of Mediterranean fruit fly and other sound-producing tephritids.