Odour Composition Variation at Different Stages of Ficus hispida Inflorescence and the Attraction to Pollinators

Abstract:

In order to understand the changes in volatile organic compounds (VOCs) of figs and its regulation to pollinators, the compositions of VOCs at three floral phases were determined in Ficus hispia, and the behavioral responses of pollinators to different developmental syconia were observed by using Y-tube olfactometer. The results showed that there were 64 compounds were detected in syconia at three phases. Among them, four compounds, such as undecane, β-elemene, β-selinene, and α-muurolene, might be the active substances attractive to pollinators. So the specific chemical signal of F. hispida to attract its pollinator was achieved by "generalization" strategy. The NMDS results showed that the VOCs of syconia at prefemale phase were similar to those at female phase, but those at interfloral phase were significantly different from those at the other two phases. There was a clear tendency for pollinators to select the syconia at prefemale and female phases, but avoid the ones at interfloral phase, indicating that there was a "push-pull" interaction mode between the figs and their pollinators. The VOCs released by syconia at pre-female phase could strengthen pollinator attraction. In addition, the VOCs vary among individuals at the same developmental phase showed VOCs emission was affected by the environment, especially at interfloral phase. These would help for understand the composition characteristics of VOCs in Ficus and the chemical signal function in maintaining fig-fig wasp mutualisms.

Key words: Ficus hispida;Inflorescence;Volatile organic compound;Chemical signal