Parasites as evolutionary drivers
I believe my own personal view on parasites up until now (like most other people) has been vastly influenced by pop culture references and the general notion that parasites are horrible. I mean, mind manipulation, puppet masters and predatory hunting by an almost invisible presence is the stuff of horror movie dreams. I had never considered the ecological diversity of parasites to be worthy of consideration because well, they are parasites! I have had an awakening and have realised that as scientists, it is our job to understand, appreciate and protect the millions of years of evolution that has gone into all living organisms. How could I have been so naive to think that parasites would not have an intrinsic role to play in every ecosystem considering the fundamentals of evolution? I can only imagine it is due to my own human limitations, I foolishly believed that I am the apex species of evolution and existence. It is a very understandable view point shared by the majority of humankind, but none-the-less wrong. We have taken the role of Earth administrators and architects; we have a bias for what we want to conserve and what part of the earth holds special value over others. The amazing thing is that parasites - the forgotten organisms - are so important for the ecosystem due to their work as equalisers. They control population numbers, and the more I delve into the complexity of their place in the world, the more complex it becomes. They have been incredibly successful because it works, perhaps they were the Earth’s first administrators, doing a fine and dandy job. The Red Queen hypothesis* displays the adaptive pressure that parasites have put onto all living organisms. Would we have the level of diversity on earth without this unique pressure? I think not. From a human perspective, the burden of parasites is huge in terms of deaths, disability and livestock loss (which further damages the reputation of parasites). But let us all remind ourselves of the fact that often the parasites causing devastating diseases have neither humans nor livestock animals as their natural hosts. Very often we have invaded the parasites’ territory, we have come between them and their natural host, we have upset the balance and continue to do so. We cut down habitats, domesticate animals and mess with things that we were not supposed to; continuously upsetting parasite ecosystems and inserting ourselves into them. I can only hope that the diversity and overall conservation of the world’s parasites may become a leading topic in science, as I do not believe we have even touched the surface regarding the essential role parasites play on earth. I think it has become very clear, that it is us, humans, that are the stuff of horror movies and nightmares! We are the master manipulators, the ultimate puppet masters and the number one predator in earth’s history!
*The Red Queen Hypothesis expresses the notion that there is a constant “arms race between co-evolving species. Named after the Red Queen in Lewis Carroll’s “Through the Looking-Glass”, who explains to Alice: “Now, here, you see, it takes all the running you can do, to keep in the same place.”
- Samantha Shippley (ANU Undergraduate student) in collaboration with Professor Alex Maier
Read more about Parasites: The Good, The Bad, and The Ugly.