Insect visitors to flowers of cultivated Ardisia elliptica Thunb. (Myrsinaceae) and Memecylon caeruleum Jack (Melastomataceae) in Singapore

This study documents the composition and behaviour of insect visitors to flowers of cultivated plants of Ardisia elliptica Thunb. and Memecylon caeruleum Jack at the National University of Singapore Kent Ridge Campus, Singapore. During a synchronous flowering of these plants from January to February 2016, six and 13 insect species were observed to visit flowers of Ardisia elliptica and Memecylon caeruleum, respectively. A comparison of floral visitors for both species showed an overlap of the principal visitor, Amegilla (Zonamegilla) andrewsi (Cockerell) for flowers of both Ardisia elliptica and Memecylon caeruleum, but the exclusive visitation of three Megachile species to Memecylon caeruleum flowers suggests the presence of two distinct guilds that frequent the flowers of Ardisia elliptica and Memecylon caeruleum. These observations, coupled with other Singapore observations, provide a baseline for understanding native pollinators for both species.