Temporal overlap of anthesis, insect visitation, and floral chemical profiles in a limestone ginger (Etlingera punicea)

Floral phenology and floral chemical traits play important roles in shaping interactions between plants and their floral visitors. However, little is known about the temporal overlap of these factors in limestone habitats. Therefore, this study aims to examine the temporal overlap between anthesis and insect visitation, and to characterise the presence of floral compounds during peak anthesis in the limestone-associated ginger Etlingera punicea. This study was conducted from March to April 2021 at Gua Setir (Kelantan, Malaysia), a limestone area. Floral phenology was assessed through systematic monitoring of anthesis stages, while insect visitation frequency was recorded using an observational method. Floral volatiles were characterised using GC/MS, while non-volatile compounds were analysed via LC/MS. Etlingera punicea flowers are short-lived, with full bloom from 0700 to 1640 h, coinciding with the activity of diurnal insects. The primary volatile compound in the floral scent is linalool, whereas lignan glycosides are among the non-volatile compounds with the strongest responses in the flower. The flower attracted four diurnal insect species, namely fruit fly (Drosophila melanogaster), shield ant (Meranoplus mucronatus), stingless bee (Tetragonula testaceitarsis), and true bug (Kosmiomiris rubroornatus). This study revealed that E. punicea features a single pollinator T. testaceitarsis, averaging 39 visits/day, entering through the floral dorsal opening and collecting pollen via mandibles and scopa. This study demonstrates that the interplay of floral phenology, chemical traits, and visitor activity shapes pollination in E. punicea at a limestone site in Kelantan, providing essential baseline information for future research on ginger pollination ecology.