Studies on diversity, abundance and pollination efficiency of insect pollinators and pollination mechanism involved in sunnhemp (Crotalaria juncea L.)

Abstract

Biodiversity of insect pollinator’s species visiting sunnhemp crop was studied in TNAU Coimbatore, India. Fifteen insect species belonging to four orders were recorded from sunnhemp flowers, of which nine belongs to order Hymenoptera, two to Lepidoptera, two to Coleoptera and one to Diptera. Among the different insect pollinators Xylocopa latipes, Xylocopa pubescens and Megachile lanata are the most frequent visitors. These are also capable of impeding pollination in sunnhemp flowers. Among different bee species maximum mean population was observed in Megachile lanata-4.72 bees/M2/5 minutes followed by Xylocopa latipes 3.65 bees/M2/5 minutes and lowest abundance was observed in case of Xylocopa pubescens (3.215 bees/M2/5 minutes). The pollination index of Xylocopa latipes (7.05) was highestfollowed by Xylocopa pubescens (6.85)and Megachile lanata (6.84). Hence it is concluded that Xylocopa latipes was the most efficient pollinator of sunnhemp flower. The seed for this potentially valuable green manure crop is largely unavailable due to paucity of pollinators and self-incompatible nature of the plant. These pollinators are able to overcome the floral barriers in sunnhemp flowers. Compared to male bees, the females are more efficient in pollinating, the male bees collect only nectar while female bees collect both nectar and pollen for the purpose of reproduction and feeding the offspring’-s.

Keywords

• Crotalaria junceaL
• Xylocopa latipes
• Xylocopa pubescens
• Megachile lanata
• vexillum
• scopae.