Earthworms

Alex Re

Hello, welcome to on wildlife. I'm your host, Alex Ray. On this podcast, we bring the wild to you, we take you on a journey into the life of a different animal every week. And I guarantee you, you're gonna come out of here knowing more about your favorite animal than you did before. On this episode, I'm going to be talking about an animal that is oftentimes overlooked, but plays an important role in our ecosystem. If you like dirt, you're in luck, because these animals spend most of their time underground. So for this episode, we're going to be looking into the soil to talk about a gardeners best friend, earthworms.

earthworms are animals that you probably see on a regular basis but don't think too much about. They can really be found anywhere in the world that has moist soil. But the term earthworm is an extremely broad category, and it can encompass over 1800 different species. Generally, they live for up to six years, and are typically only a few inches long. But some species can grow up to 14 inches and can weigh less than an ounce. But that's only in North America. If you go overseas. You may be shocked with the length of these earthworms. Dave, the earthworm lived in the UK and grew up to nearly 16 inches. But still compared to other species. Dave is pretty small. Some species can grow over six and a half feet long. The largest earthworm in the world resides in Australia, and it's called the giant gippsland earthworm. It's extremely rare and only found in five locations throughout the world. And I'm not lying when I say that they look like one of those giant gummy worms that you can buy off of Amazon. earthworms are invertebrates meaning that they don't have a backbone. And we've only talked about a few other invertebrates on this podcast like ants and butterflies. Their bodies are made up of ring like segments called an Eli, the annual eye are covered in microscopic bristles called set tie, which are used by the worm to move and burrow. And you may have heard the saying that the early bird gets the worm. Well, there's some truth to that because some earthworms feet above ground at night, and when it starts getting bright outside, they go underground. They burrow during the day, usually close to the surface. But earthworms are capable of digging six and a half feet underground. And technically they're actually an invasive species in North America because they're native to Europe. Some earthworm species were native to North America about 10,000 years ago, but then they were all wiped out during the Ice Age, but don't go around killing them. As you'll hear later on in the podcast, they could be beneficial for gardening soils, but could also be harmful to forests. earthworms are animals that will eat really just about anything. They've been described as omnivores to try divorce which means eating decaying plant and animal matter, fungal vores, which means eating fungi, and some species have even been described as geo phages, which means eating soil. And they have different diets depending on if they eat above ground or underground. On the surface, they'll eat dead leaves, grass, berries and vegetables. But underneath the surface, they eat fungi, algae and bacteria. In particular, they really like this certain type of fungus called a micro riser, which grows on the roots of certain plants. They eat about their body weight in food per day. Even though they're small, that's still a lot. Humans only eat around 4% of their body weight a day. The smaller their food is, the easier it is for them to digest and process it but how are they actually eat their food. They do have mouse which means they have a head end and a tail end, but they don't have teeth. Instead, their mouths are just really muscular. And depending on what the earthworms eat, they have different ways of getting their food. If they eat micro organisms in the soil, they usually just swallow the soil as well as what they're trying to eat. And then they have a gizzard that grinds up the food and then it goes through the intestines. When they're done digesting they leave behind worm poop, which is also called castings. And this is the stuff that's really good for gardens. Their castings have a lot of nutrients that are needed for a plant to grow such as nitrogen. And earthworms can be categorized based on what they eat and how they build their burrows. For example, amnesic earthworms build vertical burrows and eat fresh leaves, while endogenic earthworms build more horizontal burrows and feed on soil. They also try to avoid eating rotting food due to the lack of oxygen in that food. This could make their surroundings anaerobic. anaerobic just means that there's no oxygen This is because of how earthworms breathe. They don't have a complex respiratory system with lungs like we do. So how do they breathe? You'll find that out right after the break.

The person that I want to recognize On today's episode of notable figures in science is Dr. Chen Sheng Wu, who is regarded as the first lady of physics. She received her PhD in physics from UC Berkeley, and was the first female instructor at Princeton. But what she's best known for is her work on the Manhattan Project, where she figured out how to separate uranium metal by diffusion. She also created the Wu experiment, where she disproved the law of conservation of parity, which stated that identical nuclear particles don't always act the same. pretty complicated stuff.

So before the break, I said that earthworms don't have lungs. So how do they breathe through their skin, they use a process called diffusion. And broadly, this means the movement of molecules from a higher concentration to a region of lower concentration. And you can witness this in your everyday life. If you spray a can of air freshener on one side of the room, you don't immediately smell it. If you're standing on the other side of the room, you have to wait for the molecules to diffuse throughout the room. So this means that oxygen and carbon dioxide can pass through the skin of the earthworm in small amounts. But in order for this to happen, their skin has to be moist, and they release body fluids and mucus to keep themselves moist, which is why they have to remain in damp soil. And this is actually one of the reasons why earthworms like to move to the surface at night. It's cooler and the potential for them to dry up is a lot lower. And obviously earthworms are missing a lot of the structures that we have, including eyes. Even though earthworms don't have the ability to see they're able to detect light on their heads is a special tissue that helps them sense light. And this is how they know not to surface in the daytime when they could be affected by the sun. Usually earthworms like to mate on the surface, and they're hermaphroditic, meaning that they don't have a specific sex like male or female, but they don't reproduce asexually. Each earthworm can produce both a sperm and an egg, and they have both a male opening and a sperm receptacle which takes in sperm from their mate. courting is a very serious and painstakingly long process with earthworms. Partners could visit each other's burrows up to 17 times before they meet. And after meeting, each of the worms secretes a liquid from a part of their body called the clip tell them Have you ever noticed that light colored area on a worm that looks like a band aid? Well, that's the clip tell them the liquid from the clip tell them forms a tiny lemon shaped cocoon where the sperm and egg cells are deposited, and the cocoon is then buried. The gestation period is around two to four weeks, and then the baby worm is born. I'm sure you've noticed on rainy days that you see a lot more earthworms on the ground. What Why is this? Scientists have believed for a long time that the only reason for earthworms coming to the surface was to keep them from drowning in their water filled burrows. But this isn't true. Worms aren't like humans, and they can't drown like a human would. In fact, they could survive several days fully submerged in the water. Now soil experts think that it's because of migration purposes. Rain allows for an easy opportunity to move greater distances across the soil surface than they would through the soil. And worms are unable to do this when it's dry because as I talked about before, their skin has to stay moist. Some species of earthworms surface to make, but it's unlikely that so many surfers to mate in the rain. Another reason may be that the vibrations of the rain may be similar to that of predators, so they come to the surface to escape them. This tactic is actually used by fishermen who want to coax worms out of their habitat, they made vibrations in the ground which caused the worms to come to the surface. So if you want to help these worms by moving them, or in some cases, throwing them back to the soil when it's raining, you could be saving their life. And as you can probably tell earthworms use touch to communicate with each other and influence each other's behaviors. And they can actually collectively decide to travel in the same direction like a herd of cattle. And moving in clusters can really be beneficial for the earthworms because it decreases their chances of getting eaten. So when we get back from the break, I'm going to talk about the pros and cons of having these earthworms in our soil. It's trivia Time. Here's today's question, which animal can drink 30 gallons of water in 13 minutes? A a camel, be an elephant. See a pelican or D an alligator? The answer is a a camel.

Okay, we're back. I talked a little bit about how most earthworms are not native to North America. The earthworms that we know today began entering North America as soon as the early 1600s when the first European settlers arrived. And like all early settlers, they had no idea the implications that arose when bringing different species into new ecosystems. These European earthworms thrive in places like gardens and the upper layers of soil, and native earthworms, if there were any thrived deeper underground. Even though they're great for gardens, European earthworms can be destructive to forests. They stir up the soil, making nutrients more accessible the flowers and vegetables. But for plants that evolved to have deep underground roots like trees, this is taking their nutrients away. earthworms do best in younger forests, because of the specific plants like tulips and the amount of leaf litter that the plants produce, which is a favorite dish for earthworms. The worms aren't as easily found in old forests where trees like beaches aren't as appealing to the worms. So by humans cutting down old forests, we're encouraging the growth spike of earthworms. So let's talk about the benefits that earthworms can give. So one of the best things that they can do for the environment is enhance soil fertility by converting large organic matter into rich nutritious soils. They do this by shredding leaves and other vegetation and mixing it with the soil. worm poop. Like I said before, it contains a lot more nutrients than some top soils. Also, when earthworms burrow it helps to aerate the soil. And this makes it easier for water and nutrients to travel underneath the soil. And not only are they important for plants, but they're also important for a bunch of animals. They're one of the main sources of food for birds, rats and toads. And humans can benefit a lot from them too, such as for composting and as bait for fishing. Their population numbers are also going strong, which could be both good and bad. And something that you may not have thought about is that earthworms could actually help with climate change. Soils hold up to two and a half trillion tons of carbon. And researchers have found that earthworms have an impact on the amount of carbon that the soils can hold. So whether earthworms have a positive or negative impact remains unclear. Because earthworms aren't endangered, I thought I'd give you some organizations that are promoting sustainable farming and gardening practices. You should check out earthworm, the American Horticultural Society and the National sustainable agriculture coalition. Thank you so much for coming on this adventure with me as we explore the world of earthworms. You can find the sources that we use for this podcast and links to organizations that we reference at on wildlife.org. You can also email us with any questions at on wildlife dot podcast@gmail.com and you can follow us on tik tok at on wildlife or on Instagram at en underscore wildlife. Don't forget to tune in next Wednesday for another awesome episode. And that's on wildlife.

Jess Avellino

You've been listening to on wildlife with Alex Ray brought to you every Wednesday.

Transcribed by https://otter.ai