Close‐distance courtship of laboratory reared Bactrocera tryoni (Diptera: Tephritidae)

Abstract

Close-range courtship behaviours are a critical element of a species' biology but, if rapid, can often be overlooked. Beyond male chemical and audio calling, close-range courtship interactions leading to copulation in the Queensland fruit fly Bactrocera tryoni are unknown; this may be due to a true absence or because they have been overlooked and not previously investigated. We sought to resolve the close-range courtship sequence of B. tryoni and construct an ethogram of identified behaviours. Close-range video recordings of B. tryoni courtship were taken during the dusk mating window and an ethogram constructed by combining all observed behaviours which led to successful copulation and unsuccessful copulation. While the previously well-recognised male wing fanning behaviour was documented, a number of other behaviours were identified for the first time in B. tryoni courtship, including female ovipositor extension, and both male and female synchronous supination, face-to-face contact, and fore-and hind leg interactions. Analyses showed that the total duration of male synchronous supination, but not the number of occurrences, differed significantly between successful and unsuccessful males. Male foreleg interaction with the female abdomen was significantly different in both total duration and total number of occurrences between successful and unsuccessful males. The results reinforce data obtained from other Bactrocera species of simplified courtship sequences in these flies in comparison with other tephritid genera, but nevertheless courtship is more complex than previously recognised.

Spatio‐temporal distribution of sexual calling behaviour in domesticated, sterile and wild Queensland fruit fly males under field cage conditions

“…Male fruit flies typically use complex dynamic displays to attract females, which include visual, chemical and acoustic signals (‘calling’) 6–8 . Calling males release pheromones to attract females to their general location, 7 while simultaneously fanning their wings to disperse the pheromones and create an audible ‘buzz’ that attracts females at close range 9,10 . In SIT, male flies are mass‐reared, sterilised and then released into nature to disrupt the reproduction of wild populations 11 .…”

Tephritid Fruit Fly Semiochemicals: Current Knowledge and Future Perspectives

“…The release and perception of semiochemicals are often accompanied by a range of intense behavioural interactions, including wing vibration and buzzing and head rocking [ 48 , 49 , 50 , 51 ].…”

“…Courtship implies a series of ritualized actions, and it is much more complex in the genus Ceratitis , particularly in C. capitata [ 86 ], than in other tephritids, such as many species of Anastrepha [ 87 , 88 ] and Bactrocera [ 89 ]. However, recent studies are revealing that, even in species where it was believed to be simplified, such as in Bactrocera tryoni (Froggatt), courtship is more complex than previously thought [ 49 ]. During courtship, volatile chemicals are perceived by either one of both sexes using the antennae, while less volatile compounds, such as CHs, have been suggested to be important in later stages, when male and female touch each other during mating attempts and mating per se [ 35 , 42 , 90 ].…”

“…During courtship, volatile chemicals are perceived by either one of both sexes using the antennae, while less volatile compounds, such as CHs, have been suggested to be important in later stages, when male and female touch each other during mating attempts and mating per se [ 35 , 42 , 90 ]. Indeed, in several tephritids, fore- and hind-leg interactions, as well as male foreleg interaction with the female abdomen, ‘kissing’ (i.e., touching of the labella), and male tapping with the labellum on female thorax have been reported [ 42 , 49 , 91 ]. For example, in Ceratitis rosa Karsch and A. fraterculus , sex-specific differences in the quantitative composition of CH profile, together with reported mating incompatibilities, further suggest the role of CHs as short-range semiochemicals [ 90 , 92 , 93 ].…”

Acoustic characteristics of sound produced by males of Bactrocera oleae change in the presence of conspecifics

“…Tephritid males, when engaging in synchronous wing waving, hold their wings perpendicular to the long axis of their body and move them up and down repeatedly, often while moving from side to side in front of the other male (a behavior that differs greatly from the wing vibration during courtship) 33 . In B. tryoni , male synchronous wing waving is a highly significant behavioral difference between successful and unsuccessful males and may represent either a simplified courtship dance used by females to recognize males, or an indication of male activity that improves their mating success 34 .…”