Senna spectabilis (DC.) H.S.Irwin & Barneby is an invasive tree species native to tropical America and is commonly found in the forest areas of Wayanad Wildlife Sanctuary. Its aggressive growth rate and ability to quickly cover up open and degraded lands in forest ecosystems make it challenging to control its spread. Reproductive studies of S. spectabilis and its pollen-ovule ratio indicate this species is cross-pollinating. The species is self-compatible, owing to the simultaneous occurrence of xenogamy, geitonogamy and autogamy. This reproductive strategy helps the taxon to colonise degraded areas and invade the forest ecosystem. The anthesis is diurnal and sometimes asynchronous. Peak insect visitors were observed from 0900 h to 1230 h, with the major visitor being Tetragonula iridipennis. Xylocopa violaceae was also a regular visitor along with resident Formicidae members, such as Oecophylla smaragdina and Myrmicaria brunnae. They feed on the floral parts, like tender petals and sepals. The reproductive syndrome of this plant favours maximum fertilization.