Ticks have quite a bad image. They are blood-sucking parasites that infect humans and animals and can also transmit nasty diseases through their bites. It is not easy to see whether they are of any use, and what their role is in nature. So the question arises: “Why are they even there?” or “What are ticks good for?”
These questions are all too understandable when all you hear about is the dangers of being bitten by a tick and contracting a tick-borne disease. Anyway, ticks have to be good for something. Otherwise, nature would have allowed them to die out long ago.
What are ticks good for?
- Serve as food
- Are hosts to other parasites
- Aid natural selection and evolution
- Train our immune system
An important role in the food chain
Although ticks are parasites that feed on the blood of many different hosts, they are also part of the food chain and are eaten by many animals.
Ticks belong to the order of arachnids (spiders). Almost all species of spiders have a large number of predators, so ticks too, are eaten by reptiles, birds, and small mammals. Birds are among the top tick eaters, and even chickens will eat ticks if they find one.
Parasites and insects are great sources of protein and extremely nutritious. Parasitic organisms make up about half of all living species. If they were all exterminated, the entire food chain would collapse and most other living things would starve.
Ticks serve as hosts to other parasites
As we have just learned, there are a whole lot of parasitic creatures on our planet. So no wonder that ticks are also hosts to many parasites of which some kill the tick in the end.
A very common worldwide, soil-inhabiting fungi Metarhizium anisopliae infests and kills ticks.
A group of Pinworms (Nematodes) also causes trouble to ticks and many other parasites. The tiny worms slip through the segments of the exoskeleton and eat their host from within. The tick wasp, Ixodiphagus hookeri finds ticks and lays eggs in the body of the tick. The wasp larvae hatch when the tick takes its first blood meal. They then eat the tick from inside until they break the tick exoskeleton and emerge as wasps.
Ticks accelerate selection and evolution
Ticks and other parasites are likely to play a role in the evolutionary process as they affect the health and immune systems of their hosts. Animals that are weakened by parasites may die or often have fewer offspring. Some animals are less affected by the parasite and remain healthy. They can reproduce in greater numbers and pass better genetic traits on to their offspring.
These are then also resistant to the parasite and can pass it on to the next generation. Survival of the fittest, true Darwinism.
Ticks spread bacteria and viruses
For bacteria and viruses, ticks are extremely important. As the pathogens are not really mobile themselves, they rely on “vehicles” to move from one host to the next.
Parasites keep our Immune system busy
Our immune system needs a constant challenge to have an edge on all the pathogens and bugs that can make us sick. In a too clean sterile world, our immune system has nothing to do and it can sometimes turn against us. Why do you think allergies and autoimmune diseases are on the rise. When a tick bites us, a whole cocktail of viruses and bacteria enters our body and challenges the immune system. Our body has learned to deal with most of them.
However, some of these pathogens that our body has not yet adapted to lead to diseases such as Lyme Borreliosis, tick-borne encephalitis, rickettsiosis infections, Ehrlichiosis, and others. This illness can vary greatly in its severity, depending on the general state of health of the patient or whether someone has good “genes”.
So Why Are Ticks There?
Nature does not really ask such a question. In nature, you only have to look at the big picture, the interaction of many organisms, and if there is a niche to fill. And ticks have found a niche, to which they have adapted very well.
Ticks are simple creatures that don’t need much energy, they feed 2 or 3 times in their life, they don’t move much, need only a few sensory organs to detect a victim, and need only a simple nervous system to function. Once they have found a host they are quite safe while feeding. After a couple of days, they fall off, morph into the next development stage, lay eggs, and die.
Ticks are part of the Ecosystem
Everything in nature depends on each other, nature is one living organism. Parasitism is an extremely successful and widespread way of life. Ticks are successful parasites, but nevertheless, they are an annoying pest to humans.
They have found an ecological niche from which nobody has expelled them and all efforts to eradicate them at least in our immediate neighborhood seem futile. Planting tick repelling plants in our gardens and using tick repellents is all we can do to prevent tick bites and reduce the risk of tick tick-transmitted diseases.
References and Sources:
ncbi.nlm.nih.gov/books/NBK214895/
newscientist.com/article/mg21929270-300-parasitism-is-the-most-popular-lifestyle-on-earth/
bbc.com/earth/story/20150127-what-if-all-the-pests-vanished
