Also find Dr. Ellen Rotheray and "Introducing Hoverfly Lagoons" on YouTube
There are more than 250 different hoverfly species in Britain, but this project will be focussed on those species that have an aquatic larval stage. We expect these homemade lagoons to be particularly beneficial for species in the genera Eristalis and Myathropa. In recent years, there has been much concern about the decline of pollinators in the UK and across the world, potentially leading to a pollination crisis and affecting flowering plants and crop yields. Most of the attention and research has been focussed on bees, which are vital pollinators and do need to be conserved, but other pollinators, including hoverflies, are similarly important and help enhance the pollination services that our crops and plants receive.
However, some hoverfly species may be missing out on egg-laying locations, so by creating a lagoon out of a small container, for e.g. made from an empty drinks bottle packed with organic matter and water, we will be able to provide a habitat for their long-tailed larvae (so called because of their long breathing tube extending from their rear end that allows them to breath as they feed beneath the surface). To encourage the larvae to pupate near the lagoon, a pupation tray filled with drier material around the base of the lagoon container will also be needed so we can survey for pupae. If you choose to get involved, once you have set up your lagoon, we will ask you to check the material once a month for the long-tailed larvae, and record how many individuals you find. Towards the end of the project the number of pupae found in the trays can be recorded. The pupae can then be transferred to jars until emergence to allow for identification to species level. Full details about what to do will be provided upon signing up, and in monthly emails!
Keen volunteers will then be given the option of leaving their lagoons out after collecting data in October, and then searching them again in late February (email reminders will be sent out) to assess overwinter survival of larvae. You can then continue to survey the leaf litter trays every month from February for pupae and begin checking for larvae again in May. Please note that these lagoons can have a strong smell due to the decaying organic material, particularly silage, so you may wish to choose a different substrate if you have a small outdoor area.
Also find Dr. Ellen Rotheray and "Creating and Surveying Hoverfly Lagoons" on YouTube