Difference Between Mutualism and Parasitism

The main difference between mutualism and parasitism is that the mutualism is an ecological interaction between two species from which both partners benefit whereas the parasitism is another type of ecological interaction in which one partner benefits at the expenses of the second partner. Furthermore, each partner requires the other partner for the survival in mutualism while only the parasite requires the host for the survival in parasitism. 

Mutualism and parasitism are two symbiotic relationships that can occur in a particular ecosystem. 

Key Areas Covered 

1. What is Mutualism
     – Definition, Facts, Examples
2. What is Parasitism
     – Definition, Facts, Examples
3. What are the Similarities Between Mutualism and Parasitism
     – Outline of Common Features
4. What is the Difference Between Mutualism and Parasitism
     – Comparison of Key Differences

Key Terms 

Host, Mutualism, Mutualist, Parasite, Parasitism, Symbiosis 

Difference Between Mutualism and Parasitism - Comparison Summary

What is Mutualism 

Mutualism is a type of symbiosis in which both partners benefit from the relationship. The two partners of the mutualistic relationship evolve together in the ecosystem, becoming a component of it. Each component makes use of the other component and vice versa. The purpose of the mutualistic relationship varies and some of the requirements fulfilled by this type of relationship are food, transport, shelter, pollination, or defense. 

Difference Between Mutualism and Parasitism

Figure 1: Oxpeckers Eating Ticks

Some mutualistic relationships are described below. 

  • The bee or bird and flower is a mutualistic relationship based on nutritional requirements of the bee or bird and the pollination for the flower. 
  • Bacteria in the digestive tract of humans help the digestion of food while human provides shelter for that bacteria.  
  • The nitrogen-fixing bacteria live in the roots of legumes while providing nutrients to plants. 
  • The ants protect acacia plants from browsing by animals while the ants obtain food and shelter from the plant.  

What is Parasitism 

Parasitism is another symbiotic relationship, which occurs between the host and the parasite. The parasite benefits at the expenses of the host. Here, the host does not get any benefit from the parasite. But, the relationship is harmful to the host since the parasite grows, feeds, and reproduce on the host. Sometimes, the relationship can be lethal or pathogenic to the host. Usually, the parasite is smaller than the host and shows higher reproduction rates. Some parasites undergo several developmental stages inside their host. 

Main Difference - Mutualism and Parasitism

Figure 2: A Mosquito Bite

The two main types of parasites are endoparasites and ectoparasites. Endoparasites such as Plasmodium, roundworm, tapeworm, and pinworm live inside the host. Some of them live in the digestive system of the host and feed on the digestive food. Ectoparasites such as lice, mosquitoes, and fleas live on the host. Some plant parasites include aphids and insects that drink the sap.  

Similarities Between Mutualism and Parasitism 

  • Mutualism and parasitism are two types of symbiotic relationships that can occur in an ecosystem. 
  • They occur between two species within the same habitat. 
  • Both types of relationships are important for the consistency of organisms. 

Difference Between Mutualism and Parasitism 


Mutualism refers to interactions between organisms of two different species, in which each organism benefits from the interaction in some way. Parasitism refers to a type of symbiotic relationship, or long-term relationship between two species, where one member, the parasite, gains benefits that come at the expense of the host member.  This is the basis of the difference between mutualism and parasitism.


Mutualism occurs between two non-parasitic species while parasitism occurs between the host and the parasite. 


In mutualism, the two organisms need each other whereas in parasitism, the parasite needs the host, but the host doesn’t need the parasite. 


Also, mutualism is not very specific while parasitism is a kind of specific relationship. 


The relationship between bees and flowers, digestive bacteria and humans, oxpeckers and zebras, clawnfish and sea anemone, etc. are some examples of mutualism while the relationship between mosquito and human, lice on human, tapeworms in cow, and Cuscuta in plants are some examples of parasitism.  


Mutualism is a symbiotic interaction in which both species benefit from the relationship. But, parasitism is another type of symbiotic interaction in which the parasite benefits on the expenses of the host. Both species are involved in the interaction live in the same habitat. The main difference between mutualism and parasitism is the type of relationship. 


1. “Mutualistic Relationships.” Evolution, NECSI, Available Here
2. “Parasitism – Definition, Types and Examples.” Biology Dictionary, Biology Dictionary, 29 Apr. 2017, Available Here

Image Courtesy:

1. “Impala mutualim with birds wide” By Muhammad Mahdi Karim – Own work (GFDL 1.2) via Commons Wikimedia   
2. “Anopheles minimus” By Photo: James GathanyContent Provider: CDC – This media comes from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL), with identification number #7950. (Public Domain) via Commons Wikimedia 

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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