CO2 emission by Datura flowers and its significance for foraging Manduca sexta moths

C. THOM; P.G. GUERENSTEIN; E. YEPEZ; W.L. MECHABER; J. VANHAREN; J.G. HILDEBRAND; D. WILLIAMS

Florida

Congreso; Twenty-fifth Annual Meeting of the Association for Chemoreception Sciences; 2003

Association for Chemoreception Sciences

The nocturnal hawkmoth Manduca sexta feeds on nectar of Datura wrightii (Solanaceae) flowers, which produce nectar during the night. As nectar production requires high metabolic activity, a high floral CO2 emission may signal food abundance to the moths. Adult M. sexta possess a highly developed CO2-perception system. However, the role of CO2 information in the biology of this and other Lepidoptera is largely unknown. We asked if the moths could use floral CO2 emission to identify a food source. Using a state-of-the-art InfraRed Gas Analyzer, we measured CO2 release from D. wrightii flowers in the field, as well as nectar production. Our results suggest that (1) early at night, D. wrightii flowers produce CO2 levels that are well above the background and that could be detected by the moths, and (2) production of both CO2 and nectar decreases significantly during the night. We also tested the behavioral response of the moths to flowers emitting different CO2 flows. Choice experiments were done in a flight tent with artificial flowers attached to natural hostplants. Supported by the German Academic Exchange Service, and grants NIH R01-DC-02751 and NSF IBN 9983302.