Insect visitation to flowering hybrid carrot seed crops

Abstract

Although there is some literature published on insect visitation to open pollinated carrot seed crops in several regions around the world, there is none in Australasia and none on insect visitation to hybrid carrot seed crops worldwide. With a growing hybrid carrot seed crop industry in southern Australia and New Zealand, a survey of insect visitation to carrot seed crops is timely as the first step in elucidating which insects may be pollinators. Surveys of insect visitation were thus undertaken over two consecutive seasons in the south of Tasmania in order to identify potential pollinators in carrot seed crops. Sticky traps, water traps and observations were conducted within five carrot crops at three geographically independent sites to determine the variety and quantity of insects present in carrot crops. Nearly 42,000 insects were counted from observations, sticky traps and water traps. More than 100 morphological groupings were discerned. Small insects (<5 mm), most of which were thrips, made up 78% of the catch on sticky traps. Among the insects observed visiting umbels, nectar scarabs (Phyllotocus spp.) were the most abundant taxa but honey bees (Apis mellifera), muscoid flies and ladybirds were more often observed but at lower numbers. Nectar scarabs, soldier beetles and muscoid flies warrant further investigation of their role as pollinators of carrot flowers.