A signal emitted by females promotes activation and orientation in Rhodnius prolixus males

GINA B. PONTES; MARCELO G. LORENZO

Tours

Simposio; 26nd ISCE Annual Meeting; 2010

ISCE

Chagas disease affects humans and results from infection by Trypanosoma cruzi. Rhodnius prolixus (Hemiptera: Reduviidae) is the main vector of Chagas disease in Northern South America and part of Central America. The existence of a pheromone emitted during copula was reported for bugs of this species. Adult triatomines posses paired metasternal glands, whose volatile products were recently identified and reported to be released by females at night. Thus, in this study we investigated whether there is a relationship between locomotory activity and female emitted volatile signals. We first used a shelter based bioassay to characterize the activation pattern and locomotory activity of groups of males or females in the presence of potential chemical signals emitted by opposite sex conspecifics. Further, we used a dual-choice walking compensator bioassay to investigate whether female or male R. prolixus orientate in response to adult emitted odors by means of. Finally, we characterized the source of compounds that promoted orientation responses in this context. Males left their shelters significantly more frequently when groups of females were presented outside the arena in the experimental room. Besides, copulation attempts between males increased significantly under the same condition. Females showed no shelter-related activation in the presence of male odors. Additionally, males confronted with a clean air current versus an air current carrying female odors oriented significantly in the latter direction. Females did not show orientation when confronted with the different stimuli tested. Finally, females with occluded metasternal glands did not promote significantly oriented trajectories by males. Thus, our results suggest that a volatile chemical signal is emitted by female metasternal glands and, that this signal promotes the activation of sheltered R. prolixus males and their subsequent orientation when the volatiles are carried by air currents.