75% of the world’s most significant crops rely on some form of animal pollination, which equates to one-third of all global crop production.
However, insect pollinator populations have been shown to be in decline, which is a real cause for concern. Without a diverse range of pollinators, we’d miss out on tomatoes, cherries, apples, raspberries and strawberries, along with staples like coffee and chocolate. Insects pollinate the foods we love to eat.
One of the major causes of pollinator decline is loss of flower-rich habitat that provides the nectar and pollen that insect pollinators need for food. For example, in the UK we have lost 97% of ancient wildflower meadows since the 1930s, which once provided a variety of flowering plants to feed our hungry pollinators.
Growing pollinator friendly plants in our gardens is one way to increase the amount of resources available for pollinators – but which plants do pollinators like the best?
Plants for pollinators lists can be useful to help us choose the right plants, but they are generally not based on real scientific data and miss out important plants that support pollinators. Here at the National Botanic Garden of Wales we have both horticultural collections and a National Nature Reserve, with over 5,000 different types of native and non-native flowering plants for our pollinators to choose from. This puts us in an excellent position to scientifically test which plants are the most important.
PhD student Abigail Lowe used DNA metabarcoding techniques to study the pollen carried by bumblebees, honey bees, solitary bees and hoverflies. A DNA barcode is a short region of DNA used to identify species. Scientists all around the world are working together to DNA barcode all living things, allowing organisms to be identified where morphological identification is not possible. The Garden has contributed to this global effort by creating the Barcode UK database.
Insects were collected monthly across the National Botanic Garden and Waun Las National Nature Reserve and the pollen was removed. The DNA within the pollen is then extracted and the DNA barcode marker is amplified at our labs. This amplified DNA is sequenced and compared with the Barcode UK database to identify its origin.
This project aimed to discover which plants pollinators use, as well as specific questions such as whether native or non-native plants are preferred, and is there any resource partitioning between species or within species? The answers to these questions can help us inform gardeners and landowners on how to manage land in order to increase pollinator populations and prevent further decline.
Lowe A., Jones L., Brennan G., Creer S., Christie L. de Vere N., (2022) Temporal change in floral availability leads to periods of resource limitation and affects diet specificity in a generalist pollinator Molecular Ecology.
Lowe A, Jones L, Brennan G, Creer S., 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.
Lowe A. (2022) Investigating floral resource use by pollinators using pollen DNA metabarcoding PhD thesis