As adults, hoverflies feed exclusively on nectar and pollen which makes them important pollinators. Many show a remarkable mimicry of bees and wasps. They do this as a method of defence; although they are harmless, by looking like an insect that can sting, they can scare away predators.
Dr Andrew Lucas, for his PhD thesis, studied the role of hoverflies as pollinators in an iconic Welsh habitat: the marshy grasslands known in Wales as rhôs pastures. Across Britain, over 97% of species-rich grasslands have been lost. Hoverflies are likely to be important pollinators in this increasingly fragmented habitat, as well as providing a pollination ‘ecosystem service’ to the wider countryside. However, little is known of the role they play in pollen transport.
Hoverflies were collected from grassland communities and the pollen washed from their bodies. These samples were then DNA barcoded to identify the plants the hoverflies visited. The results give an indication of the range of pollen carried by hoverflies. The most frequent pollens carried include species of the family Apiacieae, such as whorled caraway and angelica, as well as bramble, thistles, elder, devil’s bit scabious, meadowsweet and heather. So far, the pollen from over 60 plant species, or species groups, has been found carried by hoverflies. The results give an insight into flower choice by individual hoverflies, and the role these insects play in pollen transport in these important grassland habitats.
Lucas, A., Bodger, O., Brosi, B. J., Ford, C. R., Forman, D. W., Greig, C., Hegarty, M., Neyland, P. J. & de Vere, N. (2018). Generalisation and specialisation in hoverfly (Syrphidae) grassland pollen transport networks revealed by DNA metabarcoding. Journal of Animal Ecology.
Lucas, A., Bodger, O., Brosi, B. J., Ford, C. R., Forman, D. W., Greig, C., Hegarty, M., Jones, L., Neyland, P. J. & de Vere, N. (2018) Floral resource partitioning by individuals within generalised hoverfly pollination networks revealed by DNA metabarcoding. Scientific Reports, 8, 5133.
Lucas, A., Bull, J. C., de Vere, N., Neyland, P. J. & Forman, D. W. (2017) Flower resource and land management drives hoverfly communities and bee abundance in semi-natural and agricultural grasslands. Ecology and Evolution. 7, 19, p. 8073-8086.
Lucas A., (2017) Hoverfly Communities in Semi-Natural Grasslands, and their Role in Pollination. PhD thesis, Swansea University.