Meet the Hoverflies
Hoverflies get their name for their fantastic ability to hover apparently motionless in mid-air. The 280 species found in Britain range from a few millimetres to two centimetres and the larvae of about 40% of them are important predators of aphids and other sap-sucking insects. Some hoverfly larvae eat plants, and others play an important role as detritivores, feeding on dead and rotting organic matter. The adults of all species are important pollinators, helping flowering plants to reproduce. Although they look like bees and wasps, hoverflies are in fact true flies, distinguishable by the fact they have only one pair of wings. They don’t bite or sting either, but mimic the black and yellow stripes of bees and wasps, which have two pairs of wings, to appear scarier than they actually are.
What they need
- Hoverflies whose larvae are carnivores require aphids and other sap-sucking bugs as food prey. Allowing some of these tiny bugs can sustain a healthy balance between them and their hoverfly predators.
- Some hoverfly larvae are commensals with bees and wasps, meaning they live alongside them in their nests feeding off scraps without harming their hosts. If you provide for the nesting needs of bumblebees you’ll therefore be helping these hoverflies too.
- Hoverflies whose larvae are detritivores require rotting and moist or wet organic matter such dead wood and leaves.
- Some species can eat pollen but most adult hoverflies drink nectar, dabbing it up with their sponge-like tongues. They therefore need a supply of accessible nectar-rich flowers over the months they’re out and about, which can vary by species from a few days to several weeks through spring and summer.
What you can do to help
- Plant butterfly-friendly flowers which are nectar rich and accessible, bearing in mind that most hoverflies don’t eat pollen.
- Grow plants that sap-suckers like aphids feed on to support carnivorous hoverfly larvae, and avoid using pesticides that would both kill hoverfly prey and poison the hoverflies themselves. If aphid populations are really getting out of hand try squishing them by hand or spraying them with soap solution.
- Incorporate features like log piles, log pyramids, leaf mould cages, compost heaps and wild patches to provide organic matter for detritivore hoverfly larvae.
- In the wild some hoverfly species lay their eggs in tree hollows that form bowls filled with stagnant water and rotting leaves. These ‘hoverfly lagoons’ are easy and a lot of fun to recreate at home. When you do, check out the perhaps not so attractive but undoubtedly fascinating and certainly harmless ‘rat-tailed maggot’ hoverfly larvae with their long breathing tubes.
Fascinating facts
- Hoverflies can hover so precisely thanks to their rapid wing beats, which can number up to 300 beats per second.
- Predatory hoverfly larvae ‘taste’ and feel their way to their prey, before piercing them with their mouth hooks and sucking out their innards. Gory!
