WHO IS MY ADVERSARY? EFFECT OF ISOMERS AND ENANTIOMERS OF PINENES ON THE MATING SUCCESS OF MEDFLY MALES

LÓPEZ M L; M. JOSEFINA RUIZ; FLAVIA JOFRE BARUD; LUCÍA GOANE; GABRIELA VALLADARES; MARÍA LAURA JUAREZ; MARÍA PÍA GÓMEZ; DIEGO F. SEGURA; JULIO A. ZYGADLO; MARÍA TERESA VERA

Congreso; 5th Congress of the Latin American Association of Chemical Ecology (ALAEQ); 2018

Plant phytochemicals affect the sexual behaviour of Tephritidae fruit fly males. In particular, (-) α-pinene, a common plant volatile enhances the mating competitiveness of Bactrocera oleae males. The objective of this study was to evaluate the effect of exposure to α- and β-pinene on the mating success of Ceratitis capitata males. Because it is recognized that enantiomers of monoterpenes have different biological activity, different enantiomers were included in the mating trials. Experiments consisted in exposing C. capitata males from a laboratory colony to α- and β-pinene enantiomers and then evaluate their sexual performance in a mating arena. Two experiments were conducted. In the first experiment, one exposed male was caged with one non-exposed male and one female. In the second experiment, competing males were exposed either to α- and β-isomers of the same enantiomer or to enantiomers of the same isomer. The number of mating pairs obtained by each type of male (mating success), the latency to mate and the duration of the copula were recorded for each treatment. Results showed that exposure of males to (-) α-pinene significantly increased the mating success over non-exposed males. Latency to mate was significantly reduced for males exposed either to (+) and (-) α-pinene compared to non-exposed males. In contrast, latency was significantly higher in males exposed to (+) β-pinene than in non-exposed males. Regarding males exposed either to equal enantiomer and isomer, results indicate that within 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 significative differences were observed for males exposed to α (-) competing with β (-) males. No statistical differences were found for copula duration. In conclusion, enantiomerism and structural isomerism are important in the mating competitiveness of medfly males exposed to pinenes. Since the mating success of treated males depended on the combination of competing males, it is suggested that a transitive relation among enantiomers or isomers is not fulfilled.