As we spoke about in Episode 12 of the podcast, parasites are extremely common throughout the world. As a quick recap, there are six types of parasitism. Those that are passed on by direct contact, such as fleas, make up the first type. Those that are eaten, like cestodes, of which tapeworms are one, make up the second type. Those that are delivered by a third-party organism. The parasite would be something like the single-cell animal that causes malaria; the third-party delivery organism in this instance would be the mosquito. There are also micropredators like mosquitoes and vampire bats that do not feed on one single host. The fifth kind would be your parasitoids. These are your wasps that paralyse or kill their prey and lay an egg on it to feed the young. These prey are then hidden so that the young have a chance to mature in safety. The last type of parasite would be parasitic castration. These parasites castrate the organism somehow and then benefit due to that action. There are some parasites that will devour the ovaries and then continue to live off the ovarian fluid, whereas there are others that will castrate their host, which stops the host from searching for mates and wasting resources producing gametes, thereby giving the parasite benefits.
With that recap complete, let's delve into two of the weirdest parasites around.
Image by Christian Gloor
Oddly enough, this one is the weirdest one I remember from the university invertebrate course. If you listened to Episode 11, we spoke about tongues in the technical section. In that episode, we spoke about how, technically, fish don't have tongues, but instead they have folds in the skin of their mouth that act like a tongue. Well, there is a type of crustacean isopod that sort of looks like a roly-poly, or wood louse. The scientific name for this nightmare fuel is Cymothoa, or the tongue-eating louse. There are numerous species of louse that have this life history.
The parasite attaches to the base of the fold that acts as the tongue using its rear legs. The tongue then seems to atrophy due to having its blood supply cut off and then falls off rather than being eaten by the parasite. Some species of these parasites feed off the fish's blood, while the majority seem to feed off the mucus produced by the fish.
The Parasitic Ant's Foot
Image by Carl Rettenmeyer/UConn Photo
This one is admittedly a strange one, although not when compared to the tongue-eating louse. In the same vein as the louse, this parasite attaches itself to the foot of an army ant. The mite then acts as the ant's new foot while it drinks the haemolymph of the ant. The haemolymph is effectively the ant's blood. There is not much known about this species of mite. It has only been found on army ants from Peru. There is some evidence that the ant may be better off with the mite acting as the foot than having the actual foot.
The species name of this mite is Macrocheles rettenmeyeri, and it is the only mite known to parasitise its host in this manner.
Well, these are two of the strangest parasitic-host relationships and they never fail to be mind-blowing. Do you have any more that you think should be added to the weirdest parasites list? Let us know on social media or comment below!