Diversity, abundance and pollination efficiency of native bees on teasel gourd (Momordica subangulata Blume ssp. renigera) in Western Ghats region of Karnataka

Abstract

The study was conducted during 2022–2024 at the research farm of ICAR-Indian Institute of Horticultural Research (ICAR-IIHR), Central Horticultural Experiment Station, Chettalli, Kodagu, India, to investigate the diversity of bee visitors, their foraging behaviour, and their pollination efficiency in teasel gourd. Six groups of native bees belonging to the families Apidae and Halictidae were observed visiting the male flowers of teasel gourd. Among them, Apis cerana indica was the predominant visitor, accounting for nearly 89% of the total bee visits, followed by Halictus spp. (8%) and Tetragonula spp. (3%). Natural visitation to female flowers was very limited; however, occasional visits by A. cerana indica and Tetragonula spp. were recorded following hand pollination. The highest foraging activity of A. cerana was recorded between 07:00 and 08:00 h, which coincided with peak floral receptivity. Different pollination methods had a significant effect on fruit yield and quality during both years of the study. Hand pollination and pollen augmentation significantly enhanced fruit set, fruit weight, fruit length, and fruit diameter compared with open pollination. Conversely, exclusion of bee visitors led to negligible fruit development, underscoring the critical role of insect pollinators in supplementing hand pollination for improved yield and fruit quality. This finding suggests that conserving and maintaining native bee populations, particularly A. cerana, together with appropriate pollination management practices, could substantially improve teasel gourd production.