Parasites are more abundant than free-living organisms in the world.

Parasites control the ecological world in number of ways. I would like to reaffirm this by using the examples from an article, “Do Parasites Rule the World?” by Carl Zimmer. Sacculina carcini, a microscopic slug plunges deep inside the depths of the crab after molting. Settling in the crab’s underside, it grows forming a bulge in its shell and sprouting a root like tendrils, which spread through out the crab’s body, even wrapping around its eye stalks. This gross invasion fails to trigger any immune response in the crab, which continues to wander through the surf, eating clams and mussels. However, if this invasion took place in a human body, the outcome would be drastic. Eventually, the crab begins to change into a new sort of a creature existing to serve the parasite. This invasion stops the crab from molting and growing as this would funnel away energy from the parasite. Crabs also lose the ability to regenerate their claw. Some parasites react to the behavior of their hosts, an interaction called social parasitism. More simply put a parasite might take advantage of the tendencies of a particular species for the benefit of its own. Further the parasitized crabs lose their ability to reproduce as this will also funnel energy from the parasite. Instead they treat the Sacculina larvae as it were its own. Infected male crabs grow abdomens as wide as those of females, wide enough to accommodate a brood pouch. This is a case where the parasite uses the host to perform a function and making life and reproduction easier on itself.

This was just one of the many examples of how parasites invade other organisms and force them to behave in a way that’s advantageous for them. From this summary it can be said that parasites do control the world. Both endo and ectoparasites have the capability of carrying and passing diseases from themselves to hosts and then possibly to predators of the host. One example of this is the deer tick which can carry Lyme disease and pass it on to humans or wildlife animals. The worst outbreaks of disease from parasites usually occur when a certain parasite first comes into contact with a specific population of hosts. An example of these ramifications would be the onset of the plague.

Parasite and host relationships hold an important part of homeostasis in nature. Parasitism is an intricate component in the regulation of population of different species in nature. Parasites exert extraordinary control over their hosts, transforming them into seemingly different creatures changing their host’s looks or scent to appeal to a predator and altering their behavior to force themselves in to the next host’s path.