Researchers at the National Botanic Garden of Wales, UK, have been using DNA barcoding to determine which plants are used by honeybees, bumblebees, solitary bees and hoverflies throughout the year.
The researchers collected bees and hoverflies along transects walked monthly from March to October, during 2018 and 2019. They found pollen from 191 different plants on the bodies of collected insects. The majority of plants visited were native and near-native, with horticultural plants providing resources later in the year.
Although they found that bees and hoverflies used many of the same plants, the plants that made the largest contributions to their diets were different. Honeybee foraging was similar to bumblebees, although they used a greater proportion of the highly invasive, non-native Impatiens glandulifera than any other insect group (Fig. 1).
The most important plants for honeybees were Ranunculus/Ficaria species and Taraxacum officinale in spring, followed by Cirsium/Centaurea/Hypochaeris species, Impatiens glandulifera and Rubus species in summer, followed by Actaea species, Heuchera species and Impatiens glandulifera in autumn.
The researchers recommend reducing lawn mowing to encourage plants such as Taraxacum officinale and Ranunculus species, and reducing scrub management to encourage Rubus fruticosus.
Figure 1. (a) Plant taxa represented by >5% of total sequence reads for each pollinator order, where Diptera includes hoverflies only, and Hymenoptera comprises bumblebees, honeybees and non-corbiculate bees. The proportion of taxa illustrated was significantly different between orders (x2 = 46.26, df = 5, p < 0.001). (b) Plant taxa represented by >5% of total sequence reads for each pollinator group within Hymenoptera.
Copyright: Lowe, A.; Jones, L.; Brennan, G.; Creer, S. and de Vere, N. Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. Licensed under CC 4.0 https://creativecommons.org/licenses/by/4.0/
Read the full paper:
Lowe, A.; Jones, L.; Brennan, G.; Creer, S. and de Vere, N. (2022) Seasonal progression and differences in major floral resource use by bees and hoverflies in a diverse horticultural and agricultural landscape revealed by DNA metabarcoding. Journal of Applied Ecology. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14144