Fleas, lice, tapeworms and ticks - these are all examples of parasites, living organisms that live on or in a host species and need this other organism to complete their complex life cycles. Sounds bad, but parasites are essential to a healthy ecosystem! And our guest for this episode says they鈥檙e also fascinating and even beautiful. Parasite ecologist Chelsea L. Wood, author of , tackles all your parasitic questions in this episode! They include: Why are there worms in our stomachs? Why do fleas bite cats and dogs? Where did head lice come from? Why do lice make you itch? Why do ticks suck our blood?
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- A parasite is an organism that lives in or on another organism and causes harm to its host.
- A broad definition of parasite includes animals, plants, bacteria, fungi and viruses.
- Parasites typically feed off of their host, or use it to complete a particular stage of their lifecycle. Sometimes they kill the host, but not always.
- People tend to think of parasites as bad, and they certainly are bad for their hosts, but on a larger scale, parasites are just a normal part of a healthy ecosystem. Think of it like a predator-prey relationship. Parasites simply have a different way of collecting their nutrition.
- Head and body lice can be found on many animal species, and they鈥檙e often very specific鈥揾uman lice don鈥檛 live on other animals, and other animals鈥� lice don鈥檛 live on us!
- Head lice live among the shafts of our hair and they eat little bits of dead skin on our scalp and can even eat our blood. That鈥檚 what causes the itching.
- Ticks are another familiar parasite. They have three different life stages and they need to take a blood meal (eat blood) in each stage. In one of the stages, the nymphal stage, these small arachnids favor a small host like a mouse. After they molt and become adults, they will attach to a larger host like a deer or a human.
- Ticks that carry Lyme disease get it from another animal, like a mouse, while taking their blood meal, and then they can pass it along to their next host, sometimes a human. So it鈥檚 always good to check your body for ticks after playing outside if you live in a place where they live.
- Tapeworms are another type of parasite. There are thousands of species of tapeworms, and only a few can live inside humans. Most tapeworms actually live inside sharks!
- Tapeworms are not sticky, despite their name.
- Some parasites are actually beneficial to our food systems. A species of parasitoid wasps kills aphids, which really like to munch on crops.
- Parasites harm their host, so we should definitely treat parasites with respect, and get medicine if we have parasites we need to get rid of. But we should also be aware of the beneficial role they play in keeping ecosystems in balance.
