Format: ORAL

Sanika Goray, Vinita Gowda

Indian Institute of Science Education and Research (IISER), Bhopal, India

Intrafloral protandry is a type of dichogamy where bisexual flowers exhibit male function at the beginning of anthesis and transition to the female phase later. This phenomenon is present in the genus Aeschynanthus Jack (Gesneriaceae). Though horticulturally popular, empirical studies on the ecology of the genus are scarce. Here, we investigate the diversity of sexual systems that are present in several species of the Indian Aeschynanthus. Our field observations revealed the presence of andromonoecy and variations in forms of andromonoecy among the Indian species of Aeschynanthus. Since andromonoecy has been reported in Aeschynanthus we explored its nature and efficiency among different species from the North East of India from an ecological perspective. We focused on achieving the following objectives during our study: 1) To investigate the presence of andromonoecy in the genus. 2) To comprehend how the allocation of floral resources (such as floral sex ratio, rewards, and display) is impacted by andromonoecy. 3) To analyze the differences in fitness (such as pollinator visitation and fruit set) among species while considering their reproductive strategies. Out of the four species studied, three were found to be andromonoecious and one was non-andromonoecious. Among the andromonoecious species, taxa with the highest nectar quality (percent sucrose) had the highest male-biased sex ratio and displayed significantly higher fitness. Interestingly, the non-andromonoecious species had similar fitness to this andromonoecious taxa and also had some of the highest nectar quality. Our findings suggest that andromonoecy enables species to improve pollen export without compromising on pollinator attraction, as there is a tradeoff between the proportion of bisexual flowers and nectar quality between species. In this sexual system of protandry and andromonoecy (protandromonoecy), protandry promotes outcrossing while andromonoecy may facilitate better pollen export and efficient resource allocation.