Allyl‐2,6‐dimethoxyphenol, a female‐biased compound, is robustly attractive to conspecific males of Bactrocera dorsalis at close range

Abstract

Insect cuticular hydrocarbons (CHCs) play important roles in mate recognition and chemical communication. To explore the cues regulating courtship and mating behaviour in the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), CHCs were extracted from mature virgin female and male oriental fruit flies using n‐hexane. Nine compounds – i.e., 4‐allyl‐2,6‐dimethoxyphenol (designated ‘compound 3’) and eight ester compounds – had significantly greater abundance in female samples than in males. Of these nine compounds, six (1, 2, 4, 5, 6, and 8) elicited electrophysiological responses from the antennae of male flies. Compound 3 did not elicit a detectable male antennal response, but in Y‐tube olfactometer bioassays, it exhibited robust attractiveness to conspecific males at close range. We speculate that compound 3 is a close‐range sex pheromone in B. dorsalis. A mating competition experiment revealed that compound 3 significantly increased the competitiveness of males, which implied that compound 3 might be used in control programs of B. dorsalis.

Cuticular Chemistry of the Queensland Fruit Fly Bactrocera tryoni (Froggatt)

“…The C 12 to C 20 esters we found in cuticle of mature female B. tryoni have also been reported in the cuticle of females in five B. dorsalis complex species, but at different relative abundances between the species, suggesting that they may have a role in species recognition [ 58 , 59 ]. On the other hand, the methyl branched fatty acid esters found in the present study have not been previously reported in either the emission profile or rectal gland extracts of B. tryoni [ 67 ], or other fruit flies.…”

“…The solvent choice of n -hexane was based on anticipated polarities of insect cuticular compounds that are generally less or non-polar [ 99 ]. The method used in the present study is more similar to methods widely used in studies of the cuticular hydrocarbons of other tephritids [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 100 ].…”

“…Frozen flies were allowed to defrost at room temperature for three minutes immediately before the following extraction procedure. n -Hexane was chosen as the extraction solvent because many cuticular compounds found in other tephritids are less, or non-polar [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 100 ]. A single fly was immersed in 400 µL of n -hexane that contained 1.5 μg/mL n -hexadecane (Sigma-Aldrich, St. Louis, MO, USA) in a 1.5 mL clear glass vial.…”

“…Beyond their use as chemotaxonomic tools, however, relatively little work has been performed on tephritid cuticular compounds. In an important recent exception, allyl-2,6-dimethoxyphenol has been proposed as a short-range male attractant in Bactrocera dorsalis [ 59 ]. Most cuticular compounds are aliphatic, so this case is also notable for its involvement of an aromatic compound.…”

Rectal Gland Chemistry, Volatile Emissions, and Antennal Responses of Male and Female Banana Fruit Fly, Bactrocera musae

“…The relative abundance of this compound is higher in headspace than rectal glands due to its lower chain length (C 12 ) and hence its higher volatility in headspace compared to the C 14 , C 16 or C 18 esters. Males of B. dorsalis exhibit EAD responses to this compound, which was found in the cuticle extraction [50]. Surprisingly, Ethyl laurate (7) [2,3,46,53,54].…”