Most people are familiar with the bumblebee and honeybee, but the solitary bee is often overlooked. In fact, 90% of bees worldwide are solitary bees. In the UK, we have more than 200 different species.
As their name suggests, solitary bees don’t live in colonies. They build individual nest cells for their larvae. Each species has very specific requirements for its nesting site. Some will excavate small tunnels in the ground while others use the hollow stems of dead plants or the holes mined by beetles in deadwood.
In the last fifty years, there has been a significant decline in the bee population. Pests and diseases are the main threats to managed honeybees. The decline in wild native bees is largely due to intensive farming practices and the increased use of pesticides both of which have led to a reduction in suitable nesting sites and fewer wildflowers.
There are a number of simple things gardeners and orchard owners can do to give our wild bees a helping hand.
- Avoid cutting hedgerows between March and September. Many plants, such as hawthorn, flower on the previous year’s growth, so hedgerows should be cut in sections every other year. Mixed hedgerows, with a wide variety of plants that have overlapping flowering periods, are ideal for bees and act as important feeding and nesting sites. They create natural corridors that enable movement between different foraging sites.
- Bees depend on the nectar and pollen from native wildflowers. Leaving patches of grass undisturbed allows weeds and wildflowers to re-colonise an area.
- Cavity nesting bees will make use of vacated beetle holes. Leave dead trees standing– if it is safe to do so – and fallen deadwood to decompose naturally.
In a future post, we will look at different ways of creating artificial nesting sites for solitary bees.