Do floral traits and rewards effects floral visitation in Syzygium parameswaranii; An Endangered evergreen tree of the southern Western Ghats of India?

Abstract

Syzygium parameswaranii is a mass-blooming endangered tree species endemic to the Western Ghats of India. The reproductive phenoevents of S. parameswaranii were significantly correlated with temperature which indicated that the flowering phenoevents should be accelerated by a specific temperature. Due to its poor floral rewards (nectar) and advertisement, a limited number of floral visitors were drawn to the blossoms of S. parameswaranii. Since there were no attractive or colourful sepals or petals, the large number of stamens served as the major floral attractant and provided pollen grains as a major floral reward because the quantity of nectar was very low. The diversity of floral visitors in S. parameswaranii was relatively limited when compared to other species of Syzygium. The flowers were attracted and visited by only twelve species including ants, bees, beetles, butterflies, moths and wasps. Among these visitors, only seven of them served as efficient pollinators. Scolia dubia was recorded with higher visitation frequency (0.78 ± 0.11) and visitor activity index (0.89) than any other visitor. Due to their frequent visits and effective stigma contact, they were recorded as the most effective pollinators of S. parameswaranii.