In ecology, a symbiote is an organism that lives in close association with another organism. Symbiosis literally means “living together.”

Let’s explore the fascinating world of forest interactions. We’ll discuss how different types of forest organisms work together to create a balanced ecosystem. From host plants and parasites to tag-team situations, we’ll learn together about the natural history of our forests. We’ll also examine how human activities can disrupt these delicate balances and lead to environmental disaster.

Join us as we take a closer look at the secret lives of forests!

What creatures have symbiotic interactions?

Symbiotes are creatures that live in close association with other organisms. Many symbiotic relationships are beneficial for both parties, but some can be harmful. The term “symbiosis” comes from the Greek word “sym” meaning “together” and “bios” meaning “life.”

There are three main types of symbiotic relationships: commensalism, mutualism, and parasitism. These three terms describe whether a relationship is beneficial, neutral, or harmful to each organism involved.

Commensalism

In commensalism, one organism benefits from the relationship while the other is neither harmed nor helped. An example of commensalism is the relationship between sharks and remora fish. The remora attaches itself to the shark and feeds on scraps of food that the shark leaves behind. The remora doesn’t harm the shark, though, with its feeding.

In a forest, we see commensalism occurring between many different species. For example, lichens, mosses, and some fungi may grow on trees without harming them. The smaller organisms benefit from the tree, but the tree has seemingly no benefit from these interactions. In other situations, new tree seedlings may benefit from the shade or protection of other organisms, like vines. These other plants may inadvertently protect new seedlings from hungry deer.

Mutualism

In mutualism, both parties benefit from the relationship. An example of mutualism is the relationship between bees and flowers. The bee collects nectar from the flower, which it uses to make honey. In return, the bee spreads pollen from the flower to other flowers, helping them to reproduce.

There is a lot of talk in the scientific world about the interactions between fungi that live in tree roots and their host plants. These fungi are very often experiencing mutualism with trees: they provide water and hard-to-find nutrients from the soil in exchange for sugars from the tree roots.

Parasitism

In parasitism, one organism benefits while the other is harmed. An example of parasitism is the relationship between fleas and mammals like squirrels. The flea will attack and feed on the squirrel’s blood, causing irritation and sometimes anemia. Fleas can also be vectors of serious disease, like tapeworms. A vector is an organism that will pass a disease onto another organism without suffering from it themselves. Insects like mosquitoes and fleas are common vectors.

Parasites are all around us. In forests, we see parasitic fungi, plants, and animals. In insects, parasites are so common that there’s actually a special word for those that ultimately kill their hosts: parasitoids. Parasitoid wasps will lay eggs inside a caterpillar and then ultimately kill the caterpillar before it ever reaches adulthood.

Another popular parasite is the “zombie fungus” that so many science and nature magazines highlight. When parasitic fungi infect ants and other insects, the fungi “mind controls” these creatures. Ultimately, they crawl up a tall surface and die. This allows the fungi to fruit from the insect body and spread its spores to more insects.

Complex symbioses

However, symbiotic relationships are not always so clear. Many symbioses are more complex with both benefits and harms for both parties involved. Scientists are learning more and more about symbioses every year. Sometimes new knowledge of species interactions upends our understanding of those relationships.

For example, fungi that live in the soil usually help plants. But a plant under certain conditions can have its helpful fungi become parasitic. The fungi then leech nutrients from a plant or tree without giving back. Interactions in nature are complex and amazing!

How symbiotes help forests thrive

Symbiotic relationships are all around us, and they play an important role in keeping our ecosystems healthy. An individual plant may have relationships with insects, other plants, fungi, and even bacteria or other microscopic organisms.

In a forest, for example, trees rely on symbiotic relationships with fungi and bacteria to obtain nutrients and water. The fungi form a network of filaments called mycelium. This network connects the roots of different trees, exchanging water and minerals between them. This relationship is beneficial for both the trees and the fungi. The trees get the resources they need to grow, and the fungi get access to the carbohydrates that photosynthesis produces.

Similarly, bacteria in the soil help to convert dead leaves and other organic matter into nutrients that plants can use. As different microscopic species recycle nutrients, other organisms in forests have better growth and survival. These symbiotic relationships are essential for the health of forests, and they play a vital role in maintaining the balance of our ecosystems.

Science shows us that these interactions are crucial for healthy forest growth and survival. Soil-based fungal species enhance the ability of trees to grow. Trees grow taller, absorb more carbon, and ultimately provide more “ecosystem services” to humans. Evidence points to symbiotic interactions having a critical effect on the growth of our ecosystems.

The benefits of having symbiotic forests near your home

Forests are complex natural systems where different species work together to provide a variety of benefits. These benefits are collectively known as ecosystem services. Ecosystem services include cleaning the air, fortifying the soil, and providing space for humans and animals to live, work, and play.

For example, forests help to clean the air. One tree can absorb several pounds of pollution per year. A mature tree can absorb 48 pounds of carbon dioxide in a year! Different trees absorb at different rates, so having a natural forest instead of a plantation can purify the air more effectively.

Additionally, forests help to regulate the climate. They can provide shade and cool the air in hot weather. They release water vapor into the atmosphere, which traps heat and keeps the environment warm in cold weather. Forests also remove carbon dioxide from the air and store it safely in trunks, branches, and soil.

In addition, forests can also protect against soil erosion and reduce the risk of floods. The roots of these forests grow deep into the soil, holding it in place and preventing heavy rains from washing it away. Forests provide many more benefits than I can list here. Can you think of others?

How to learn more about symbiotes in your own backyard

Creating a symbiotic garden is a great way to encourage biodiversity and improve the health of your plants. Symbiotic gardens are based on the principle of mutually beneficial relationships between different species of plants, animals, and microbes.

In order to create a symbiotic garden, you must choose plants that will support each other’s growth. For example, legumes such as beans and peas can be planted alongside other plants to provide them with nitrogen. Legumes have “nitrogen fixing bacteria” in their roots in special structures called nodules. At the end of the growing season, you can remove the legumes from the soil and actually examine their roots. You’ll see symbiotic interactions up close and personal.

You could also grow other plants that work well together. For example, planting mint alongside your more important plant(s) can help repel mice and other pests before they eat your garden. While most of us use netting to ward off cabbage butterflies, you can also plant tomatoes or peppermint to drive them away. Or, you can plant yarrow or buckwheat to help you attract insect predators that will eat caterpillars before they damage your broccoli plants.

By creating a symbiotic garden, you can create a more efficient ecosystem in your own backyard. You can also use it as a great way to study the interactions among individual plants, soil, and other organisms in your own backyard. Backyard gardens are great tools for scientific discovery for homeschool students and science nerds!

And…Action!

We hope you’ve enjoyed learning about symbiotes and how they can help make our world a healthier place. Do you want to learn more about biodiversity in your backyard?

Share your favorite symbiosis picture and tag us on Instagram, Facebook, or Twitter!

Want to do more?

Become a Forest Defender today! Your monthly gift will protect the biodiversity of the South.

Join our email list to get new Biodiversity in Your Backyard stories sent directly to your inbox!

Check out the other blogs in our Backyard Biodiversity series!