Who is my adversary? Effect of isomers and enantiomers of pinenes on the mating success of medfly males

RUIZ JOSEFINA; VALLADARES GR,; DIEGO SEGURA; JOFRE BARUD; JUARES MARIA LAURA; J. A. ZYGADLO; LOPEZ ML; LUCIA GOANE; GOMEZ MARIA PIA

Valparaiso

Congreso; . 5th Congress of the Latin American Association of Chemical Ecology; 2018

Asociacion Latinoamerica de Ecologia Química

Plant phytochemicals affect the sexual behaviour of Tephritidae fruit fly males. Inparticular, (-)-α-pinene, a common plant volatile enhances the mating competitiveness ofBactrocera oleae males. The objective of this study was to evaluate the effect ofexposure to α- and β-pinene on the mating success of Ceratitis capitata males. Because itis recognized that enantiomers of monoterpenes have different biological activity,different enantiomers were included in the mating trials. Experiments consisted inexposing C. capitata males from a laboratory colony to α- and β-pinene enantiomers andthen evaluate their sexual performance in a mating arena. Two experiments wereconducted. In the first experiment, one exposed male was caged with one non-exposedmale and one female. In the second experiment, competing males were exposed either toα- and β-isomers of the same enantiomer or to enantiomers of the same isomer. Thenumber of mating pairs obtained by each type of male (mating success), the latency tomate and the duration of the copula were recorded for each treatment. Results showedthat exposure of males to (-) α-pinene significantly increased the mating success overnon-exposed males. Latency to mate was significantly reduced for males exposed eitherto (+) and (-) α-pinene compared to non-exposed males. In contrast, latency wassignificantly higher in males exposed to (+) β-pinene than in non-exposed males.Regarding males exposed either to equal enantiomer and isomer, results indicate thatwithin α-pinenes, males exposed to α (+) showed higher mating success than α (-)males.On the other hand, when males were exposed to the same enantiomer, males exposed to β(+) were more competitive than males exposed to α (+), while no significativedifferences were observed for males exposed to α (-) competing with β (-) males. Nostatistical differences were found for copula duration. In conclusion, enantiomerism andstructural isomerism are important in the mating competitiveness of medfly malesexposed to pinenes. Since the mating success of treated males depended on thecombination of competing males, it is suggested that a transitive relation amongenantiomers or isomers is not fulfilled.