Hoverfly Lagoons

Project Lead: Dr. Ellie Rotheray

Running: May to Oct (can join at any point)

Why choose this project?

The decline of pollinators in the UK and worldwide is of real concern, potentially leading to a pollination crisis and affecting flowering plants and crop yields. Much of the attention and research has been around bees, but other pollinators are similarly important and help enhance the pollination services that our crops and plants receive. This project focuses on hoverflies - an often overlooked, yet vital part of our wild environment. There are more than 280 hoverfly species in the UK, and Hoverfly Lagoons focuses on those that have an aquatic lifestage, with larvae that live in pools of water or 'rot holes' in trees (particularly the genera Eristalis, Myathropa and Helophilus).

How can I help?

Our gardens often lack these aquatic habitats, providing little egg-laying space for the flies, thus Hoverfly Lagoons encourages you to create small homemade hoverfly havens from discarded milk bottles and fallen leaves. We want to work out what are the best ways to make these lagoons - so we need your help, and gardens!

This year we are interested to know how ponds in gardens affect recruitment of hoverflies to Hoverfly Lagoons. If you don't have a pond or a body of water in your garden you can still take part in this project! See the protocol below.

Project Protocol

The Hoverfly Lifecycle

What did we find last year?

Last year, we asked volunteers to help us determine if ponds affect hoverfly recruitment to Hoverfly Lagoons in gardens. Volunteers placed two identical Lagoons in their gardens: one beside the pond and one as far away as possible but still within the garden.

Findings:

June: More hoverfly larvae were recorded in Lagoons in gardens without ponds. In gardens with ponds, more larvae were found in Lagoons beside the ponds.
July: More larvae were found in gardens without ponds, but there was no difference between Lagoons near ponds and those further away.
August: Overall, more larvae were recorded from Lagoons. The average number of larvae was similar in gardens with and without ponds, but more larvae were found in Lagoons further away from ponds.

Conclusion: Early in the season, small water bodies in gardens may be crucial, especially in gardens without ponds. Later in the season, Lagoons become important regardless of pond presence, possibly due to species preferences or competition, or to drier or hotter conditions.

Next Steps: We need more data, so we're repeating the project this year to further explore the effect of ponds on hoverfly recruitment. Whether you have a pond or not, we need equal participation from gardens with and without ponds!

What do you get out of it?

By taking part in this project, you will be helping to conserve hoverflies and aid the efforts to prevent the pollinator crisis. At the same time, you will be increasing the ecological value of your garden and increasing your pollination rates.