Earthworm Love is Cuddly ... and Complicated | Deep Look

Earthworms know a thing or two about romance. They cozy up with a mate inside tubes of slime, then follow a series of intricate steps to make cocoons full of baby worms. ** TAKE OUR NEWSLETTER SURVEY: DEEP LOOK is an ultra-HD (4K) short video series created by KQED in 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. --- You can tell an earthworm is ready to mate once it has grown a fleshy patch called a clitellum. When it sidles up to another earthworm, their bodies point in opposite directions, and the worms surround each other with tubes of slime exuded from their skin. The earthworms embrace by using flaps on their clitella, and exchange sperm that travels outside their bodies. As they snuggle, the sperm flows into internal storage sacs. After mating, an earthworm produces a sheath with its clitellum that it shimmies down its body. The protein-rich ring moves over tiny holes, where it gathers eggs and some of the collected sperm. Then, the ring slips off the worm to become a cocoon with one or more developing earthworms inside. --- How do earthworms help the soil? Earthworms eat tiny bits of degraded plants, which have bacteria and fungi growing on them. This organic matter might be in the soil or in leaf litter on the surface. Some earthworms eat manure. When they poop out the remains, earthworms make nutrients like nitrogen available for plants to grow. And the earthworms that live underground spread around their nutritious poop, known as castings. “Subsoil comes up to the top, topsoil goes down towards the middle or bottom,” said Sam James, who studies earthworms at the University of Iowa. “And you can see the difference in colors of these two layers of soil.” Earthworms also create channels in the soil through which air and water can move, he added. --- What is worm composting? Earthworms such as the species Eisenia fetida can be kept in a bin and fed certain types of food scraps. Using earthworms to dispose of leftovers in this way is also known as vermicomposting. --- Can earthworms reproduce without sex? Yes. Some earthworms can reproduce on their own, through a process called parthenogenesis. These earthworms are all mothers — they don’t make sperm, only eggs. Their offspring develop from eggs that divide into identical copies. “They just clone themselves,” James said. “So what it means is a single individual can start a new population.” --- Find a transcript on KQED Science: --- More Great Deep Look episodes: Watch This Bee Build Her Bee-jeweled Nest Born Pregnant: Aphids Invade with an Onslaught of Clones You Can’t Unsee the Assassin Bug’s Dirty Work --- Shoutout! 🏆Congratulations🏆 to these fans on our Deep Look Community Tab to correctly answer our GIF challenge! SHABOOLA Vizal Pepe Pueblo Preet Budhwani Grim --- Thank you to our Top Patreon Supporters ($10 per month)! Burt Humburg Karen Reynolds Companion Cube Daisuke Goto David Deshpande Chris B Emrick Tianxing Wang Wade Tregaskis Mark Jobes Blanca Vides Kevin Judge Laurel Przybylski Cindy McGill monoirre Roberta K Wright Titania Juang Supernovabetty Syniurge KW Carrie Mukaida El Samuels Jessica Hiraoka Jellyman Mehdi Nicky Orino Cristen Rasmussen Kelly Hong SueEllen McCann Noreen Herrington Louis O’Neill Laurel Przybylski Nicolette Ray Caitlin McDonough Jeremiah Sullivan Levi Cai TierZoo Delphine Tseng Elizabeth Ann Ditz Rory B. --- Follow Deep Look and KQED Science on social: @deeplookofficial Instagram: Twitter: --- About KQED KQED, an NPR and PBS member station in San Francisco, 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. #earthworm #deeplook