Characterization and Generation of Male Courtship Song in Cotesia congregata (Hymenoptera: Braconidae)

Abstract

BackgroundMale parasitic wasps attract females with a courtship song produced by rapid wing fanning. Songs have been described for several parasitic wasp species; however, beyond association with wing fanning, the mechanism of sound generation has not been examined. We characterized the male courtship song of Cotesia congregata (Hymenoptera: Braconidae) and investigated the biomechanics of sound production.Methods and Principal FindingsCourtship songs were recorded using high-speed videography (2,000 fps) and audio recordings. The song consists of a long duration amplitude-modulated “buzz” followed by a series of pulsatile higher amplitude “boings,” each decaying into a terminal buzz followed by a short inter-boing pause while wings are stationary. Boings have higher amplitude and lower frequency than buzz components. The lower frequency of the boing sound is due to greater wing displacement. The power spectrum is a harmonic series dominated by wing repetition rate ∼220 Hz, but the sound waveform indicates a higher frequency resonance ∼5 kHz. Sound is not generated by the wings contacting each other, the substrate, or the abdomen. The abdomen is elevated during the first several wing cycles of the boing, but its position is unrelated to sound amplitude. Unlike most sounds generated by volume velocity, the boing is generated at the termination of the wing down stroke when displacement is maximal and wing velocity is zero. Calculation indicates a low Reynolds number of ∼1000.Conclusions and SignificanceAcoustic pressure is proportional to velocity for typical sound sources. Our finding that the boing sound was generated at maximal wing displacement coincident with cessation of wing motion indicates that it is caused by acceleration of the wing tips, consistent with a dipole source. The low Reynolds number requires a high wing flap rate for flight and predisposes wings of small insects for sound production.

Domestication of tomato has reduced the attraction of herbivore natural enemies to pest‐damaged plants

“…Our C. congregata colony was originally derived from individuals provided by Dr Karen Kester's colony in 2012 (origin information provided in Bredlau et al ., ) and then supplemented with wasps annually from local populations collected on tomato and tobacco in Indiana. For all experiments, we used mated females that were 6–8 days old with no prior access to hosts for oviposition.…”

Combined use of herbivore‐induced plant volatiles and sex pheromones for mate location in braconid parasitoids

“…HIPVs are released in large amounts as a bouquet of semiochemicals with relatively low molecular weight, highly suited for detection at relatively long distances (up to several metres or more; Dicke et al ). Once they are in host‐damaged plants, short‐range visual, wing vibrations and chemical cues may be effective to locate and court the opposite sex (Bredlau et al ; Godfray ; McAuslane et al ; Tagawa & Hidaka ). We have evidence that the sex pheromone of female C. glomerata is composed of relatively large molecules of low volatility working at a relatively short range (unpublished data).…”

Singing on the wings! Male wing fanning performances affect female willingness to copulate in the aphid parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae: Aphidiinae)

“…The analysis of the courtship sequences of parasitic Hymenoptera frequently identifies cues that represent selective filters to mating, which are crucial for successful mass‐rearing procedures, as well as for optimizing studies on the natural or released populations of these beneficial insects (Rungrojwanich & Walter, ; Benelli et al ., ). Among parasitic wasps, wing fanning is commonly displayed by courting males (Gordh & DeBach, ; Villagra et al ., ; Bredlau et al ., ; Benelli et al ., , b), and is considered as one of the most significant courtship parameters (Bourdais & Hance, ). Wing fanning behavior mediates the orientation of males to females in Ichneumonidae (Vinson, ), contributes to communication (Danci et al ., ; Joyce et al ., ; Canale et al ., ), and affects female receptivity (Field & Keller, ; Kimani & Overholt, ; Benelli et al ., ) in Braconidae, and induces sexual receptivity in Pteromalidae (Miller & Tsao, ; van den Assem & Putters, ; Benelli et al ., ).…”