Algunos aspectos fisiológicos de la selección sexual / Some physiological issues of the sexual selection

La atracción y el cortejo sexual integran el contexto de la selección sexual. En los humanos, complejos mecanismos psicológicos y sociales son probablemente los mayores determinantes de la atracción sexual. Si bien se postula la participación de factores de índole genética ­-que podrían explicar la importancia de los rasgos fisicos en la elección del compañero sexual (teoría de los buenos genes)-, está por otra parte comprobado que los cambios fisiológicos (espontáneos en la mujer e inducidos en los hombres) juegan un preponderante papel a los fines de la reproducción.

The attraction and courtship are inclusive parts of the sexual selection. Very important psychological and social mechanisms are possibly the main determinants of the sexual attraction in humans. The genetic participation is assumed as the explication of the preeminent importance of the physical characteristics (the good gene theory). The physiologic changes associated with the sexual selection (spontaneous in women and induced in males) play a very important role in the essence of the sexual selection: the reproductive possibility.

Efeito de fatores endógenos na percepção química de Grapholita molesta(Busck) (Lepidoptera: Tortricidae) ao feromônio sexual / Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone

The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of field results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control.

More about the role of 2,6-dichlorophenol in tick courtship: identification and olfactometer bioassay in Amblyomma cajennense and Rhipicephalus sanguineus

This study aimed to identify 2,6-dichlorophenol (2,6-DCP) in Amblyomma cajennense and to evaluate its role in A. cajennense and Rhipicephalus sanguineus courtship. Hexanic extract from attractive females was purified by solid phase extraction and the phenol was identified by the single ion monitoring method using GC/MS. In an olfactometer, the responses of A. cajennense and R. sanguineus males to females, control rubber septa or rubber septa impregnated with 2,6-DCP at 50, 500, and 5000 ng, respectively, were studied. 2,6-DCP was identified in A. cajennense extract and the males oriented themselves toward the concentration of 500 ng. These septa and the females were recognized as copula partners. The septa treated with 2,6-DCP did not attract and were not even recognized by the R. sanguineus males, whereas the females were recognized. Due to the presence of 2,6-DCP in A. cajennense and the results of biological bioassays, it was concluded that this compound acts as an attractant and mounting sex pheromone in this tick, but it does not play any role in R. sanguineus courtship.