Tapeworms are found in all kinds of vertebrate animals, and while their life cycles and transmission usually rely upon parasitised prey being eaten by predatory final hosts, some tapeworms have evolved ways to infect herbivorous animals as well. Anoplocephala is a genus of tapeworms that parasitise a wide range of herbivorous mammals including elephants, rhinos, hyrax, zebras, and more. The most well-studied species is Anoplocephala perfoliata because it happens to be a parasite of horses, and heavy infection with that tapeworm can cause gastrointestinal diseases. But the species featured ..read more

There are many ways to become a parasite, and there are parasites with vastly different ancestries that end up joining the same path on the road of parasitism. In some cases, sharing the same path can also mean adopting a certain shape. This post is about Veneriserva pygoclava, a worm that lives inside a worm, more specifically it is a polychaete worm that has evolved to parasitise another type of polychaete worm which are commonly called "sea mice". Top left: Ventral view of an infected Aphrodita longipalpa with a Veneriserva pygoclava parasite inside. Bottom Left: MicroCT scan i ..read more

To land-dwelling humans, deep sea hydrothermal vents would seem like a vision of hell, amidst the crushing darkness you have plumes of superheated water, mixed with noxious sulfides, erupting from fissures on the seafloor. But for many deep sea animals, this "hell" is in fact a vibrant oasis in the middle of the abyss. This lively habitat is made possible thanks to bacteria that are able to extract energy from the sulphurous waters billowing from those vents. In the absence of sunlight, these chemoautotrophs form the foundation of the food chain. Some tube worms have been able to co-opt t ..read more

This parasite is invisible to the naked eye, can kill its host in 3 days, and it can be found lurking in the waters of rice fields. What I have just described may sound like a nightmare pathogen from a b-horror movie, but it is actually a microscopic flagellated protozoan that has given up a solar-powered life for one fuelled by the blood of its victims. The name of this microscopic monster is Euglenaformis parasitica, and it belongs to a group of otherwise innocuous single-celled critters called Euglenids. Left: Scanning electron micrograph of Euglenaformis parasitica. Top Right: E. pa ..read more

Strepisptera is an order of parasitic insects with some very unique characteristics.They are also known as twisted wing parasites, based on the twisted hindwings on the male parasite. They infect many different orders of insects, but mostly target wasps and bees where they up take up residency in the host's abdomen. If you know what to look for, you can immediately spot their presence. In fact, there's even a special term for describing bees and wasps that are parasitised - they get "stylopized". Top: A male Stylops ater (indicated by red arrow) attempting to mate with a female in a bee ..read more

In Lake Alexandrina of New Zealand lives a species of tiny freshwater snail called Potamopyrgus antipodarum. These snails are capable of alternating between sexual and asexual reproduction and can be extremely abundant. So much so that they have become invasive in many other parts of the world. Outside of their original home, they are free to proliferate to their heart's content. But back in New Zealand, these snails don't always have things go their way. They are held back by a whole menagerie of flukes which parasitise them - at least 20 different species in fact. Top: Photo of the s ..read more

Parasitism has evolved a few different times in barnacles. Most parasitic barnacles belong to a group called the rhizocephalans, which are body-snatchers of decapod crustaceans like crabs and shrimps. Aside from them, there are two other known genera of parasitic barnacles: Anelasma squalicola - which is the bane of deep sea Squaliform sharks, and then there's the barnacle being featured in today's post - Rhizolepas, a rare little crustacean that parasitises seafloor-dwelling aphroditid scale worms. Both of them belong to a group called Thoracicalcarea, which happens to be a sister g ..read more

Student guest post time! One of the assessments that I set for students in my ZOOL329 Evolutionary Parasitology class is for them to summarise and write about a paper that they have read in the manner of a blog post. The best blog posts from the class are selected for re-posting (with their permission) here on the Parasite of the Day blog. So from the class of 2023, here’s a post by Nikita Sheelah, about a bird of prey with too many flukes. To dare to do what hasn’t been done before has been the driving force behind many advancements in society, such as the creation of vaccines, anime, or the ..read more

The study in this post takes us to one of the darkest corners of the deep sea, over 7000 m below sea level in the Kuril-Kamchatka Trench, located in the northwestern Pacific. Living in this dark and oppressive environment are isopods called Eugerdella kurabyssalis. And despite the crushing pressure, these crustaceans like it just fine, in fact they are the most abundant isopod down in those depths. But such success and abundance can also attract the attention of parasites, and this post is about a newly described parasitic copepod called Diexanthema hakuhomaruae. Left: Diexanthema hakuh ..read more

The horned passalus beetle (Odontotaenius disjunctus) is an insect that is commonly found in rotting logs. These beetles do more than just eat wood, they excavate extensive tunnels within those logs where they would mate and raise a whole family of baby beetles. By doing so, they play an important ecological role in breaking down dead wood and making their nutrients accessible to other organisms in the forest such as bacteria and fungi. Top: A piece of dead wood with burrows made by the horned passalus beetle. Bottom left: A horned passalus beetle. Bottom right: Chondronema passali ..read more