There are certain interactions in which both parties benefit, and those types are called mutualistic relationships. For example, one incredibly cool mutualistic relationship involves crabs and sea urchins! In the waters around Indonesia, there are crabs called urchin crabs that carry fire sea urchins on their backs as they traverse the ocean floor. Why do they do that you may ask? Because fire sea urchins are quite venomous and act as an effective shield against potential predators. What does the sea urchin get out of this relationship? A free ride of course! Watch these two animals work together in their mutualistic relationship.
Commensalism is a relationship where one party benefits and the other party neither benefits nor is harmed. A great example of this type of symbiosis is between the caterpillar stage of the Monarch Butterfly and milkweed. Great fields of milkweed act as important nurseries for the monarchs and is where the monarch picks up its best strategy for defense. Within the leaves of the milkweed lie toxic chemical components that the munching monarch caterpillars assimilate into their own bodies, acting as a chemical defense against predators! Learn more about this important relationship from National Park Rangers in Yosemite.
However, some of the most fascinating relationships are those classified as parasitic, a relationship where one organism will benefit while the other is harmed or even dies. The Lancet Liver fluke cycles through its life within the bodies of three different animals. As an adult, the fluke can be found in the liver of a cow or sheep, and after mating, the eggs of the fluke will be in the feces of the host. This is the part when a snail comes along and gobbles up the eggs without knowing, unwittingly becoming the second host to the fluke. After the eggs hatch inside of the snail, the baby flukes work their way to the surface and agitate the snail until it coughs up the parasites in slime balls. The next host is an ant, who then stops by to snack on the snail slime, thereby ingesting the fluke larvae. This is where things really get interesting. The fluke larvae attack the ant’s brain and essentially take over, controlling the ant to position itself at the tops of plants during dawn and dusk! Why do they do this? So that the likelihood of the ant being eaten by a grazing mammal increases dramatically and the fluke can complete its life cycle. Learn more about the Lancet Liver fluke!