How Hoverflies Spawn Maggots that Sweeten Your Oranges | Deep Look

Oblique streaktail hoverflies zip from bloom to bloom wearing a wasp costume to avoid getting eaten. But it’s all for show – they don’t even have stingers! Their fierce maggots, on the other hand, devour hundreds of insect pests. As they gorge, they help keep orange trees safe from disease. TAKE OUR SURVEY! DEEP LOOK is an ultra-HD (4K) short video series created by KQED San Francisco and presented by PBS Digital Studios. See the unseen at the very edge of our visible world. Explore big scientific mysteries by going incredibly small. --- Entomologist Nic Irvin, at the University of California, Riverside, has found that the maggots of oblique streaktail hoverflies eat more than 400 Asian citrus psyllids in the week before they transform into pupae. Orange growers despise Asian citrus psyllids, which spread a destructive bacterium when they feed on the sap of citrus trees. The bacterium, Candidatus Liberibacter asiaticus, causes a disease known as citrus greening or huanglongbing. Infected citrus trees make green, bitter fruit and eventually die. Irvin has planted alyssum, a plant with fragrant white flowers, in orange groves near Riverside. The alyssum attracts adult oblique streaktail hoverflies that feed on its pollen and then lay their eggs on orange trees under attack by Asian citrus psyllids. When hoverfly maggots hatch out of the eggs, they devour the psyllids. In one experiment, Irvin found that having alyssum near orange trees reduced by 10% the number of Asian citrus psyllids on them. --- Are hoverflies good for the garden? Yes, hoverflies help backyard gardeners too. They pollinate flowering plants. And their maggots feed on aphids, a common pest of vegetables. --- How do hoverflies fly? Hoverflies fly like tiny helicopters – they can hover, fly straight up and down and backward and turn in almost every direction, said Karin Nordström, who studies hoverflies at Flinders University in Australia. “Seeing them come in and land on a flower, it’s really beautiful,” she said, “because it’s such a controlled landing.” --- Find additional resources and a transcript on KQED Science: --- More great Deep Look episodes: This Bee Gets Punched by Flowers For Your Ice Cream Born Pregnant: Aphids Invade with an Onslaught of Clones This Freaky Fruit Fly Lays Eggs in Your Strawberries --- Shoutout! 🏆Congratulations🏆 to these fans on our Deep Look Community Tab to correctly answer our GIF challenge! TheWhiteScatterbug Cesalia Floof DizzyDragon --- Thank you to our Top Patreon Supporters ($10 per month)! Burt Humburg Karen Reynolds Daisuke Goto Allison & Maka Masuda David Deshpande Chris B Emrick Tianxing Wang Wade Tregaskis Companion Cube Mark Jobes Blanca Vides Laurel Przybylski Kevin Judge Aurora monoirre Anastasia Grinkevic Titania Juang Syniurge Supernovabetty Roberta K Wright El Samuels KW Jessica Hiraoka Carrie Mukaida Jellyman Mehdi Nicky Orino Cristen Rasmussen Cindy McGill Noreen Herrington SueEllen McCann Laurel Przybylski Shelley Pearson Cranshaw Caitlin McDonough Kelly Hong Nicolette Ray Louis O’Neill Jeremiah Sullivan Elizabeth Ann Ditz TierZoo Levi Cai Silvan Delphine Tseng Kenneth Fyrsterling --- Follow Deep Look and KQED Science on social: @deeplookofficial Instagram: Twitter: --- About KQED KQED, an NPR and PBS affiliate in San Francisco, Calif., serves Northern California and beyond with a public-supported alternative to commercial TV, radio and web media. Funding for Deep Look is provided in part by PBS Digital Studios. Deep Look is a project of KQED Science, the largest science and environment reporting unit in California. KQED Science is supported by the Dirk and Charlene Kabcenell Foundation, Campaign 21 and the members of KQED. #hoverflies #asiancitruspsyllids #deeplook