5 Parasites That Plague Other Parasites

Can you be a host and a parasite at the same time? The answer is a stomach-turning “yes.” Like grotesque Matryoska dolls, naturalists sometimes find parasites within parasites.


Brain-controlling parasites sound like the villains of a cheap sci-fi movie. But make no mistake: They’re all too real.  Just ask an ant.

Members of the Ophiocordyceps fungal genus have evolved to attack a specific type of ant. In order to grow properly, these fungi need a patch of earth that meets several very specific conditions (perfect temperature, humidity, distance from the ground, etc.). But it needs transportation to get there.

When the right Ophiocordyceps encounters the right host, things get weird fast. Fungal spores infect the ant's brain, and literally control its mind. It drives the ant to prime Ophiocordyceps real estate, where the ant bites down onto a leaf and dies. After the ant expires, thread-like filaments spread through its body. These soon breach the exoskeleton and, before long, new Ophiocordyceps spores rupture the ant’s head, ready to repeat this cycle of mayhem.

A third player in this Jacobean drama was revealed in 2012. A team led by Penn State biologist David Hughes discovered a second fungus—one which saves countless ants from mental enslavement. This currently nameless organism turns the tables and makes a host out of Ophiocordyceps itself. “The hyperparasitic fungus effectively castrates the zombie-ant fungus so it cannot spread its spores,” Hughes says.


Man’s best friend is a four-legged flea magnet. Multiple species target canines, with the aptly named dog flea (Ctenocephalides canis) being the most widespread. It also can infect the skin of felines and—occasionally—humans. 

Apart from being annoying, the flea can be a Trojan horse for a far more dangerous parasite. Larval fleas frequently eat the eggs of double-pored dog tapeworms. These hatch into cysticercoids (tapeworm larvae), which bide their time inside the flea’s intestines while the arthropod grows up. Should a dog, cat, or human accidentally swallow an infected flea, the cysticercoid will break out and develop into a mature, full-length tapeworm. Upon becoming sexually active, this segmented creature releases eggs that the host later poops out. Fleas then gobble them up, and the cycle repeats itself.


Any parasitic organism that invades another one is called a “hyperparasite.” And then we have A. californicus, which counts as a “hyper-hyperparasite.” Pea aphids (Acyrthosiphon pisum) are red and green sap-suckers that can be found throughout much of Europe and North America. Commonly regarded as pests, the bugs are vulnerable to Aphidius smithi: a wasp whose larvae live inside them and mooch off the aphids’ food supply.

Life isn’t exactly a cakewalk for these freeloaders, however. Aphidius smithi larvae can themselves become infected by the larvae of another wasp: Alloxysta victrix. Those, in turn, will sometimes harbor A. californicus larvae. So, to recap, a single aphid might well have a parasite that has a parasite that has a parasite. Isn’t nature delightful?


As the old cliché goes, the enemy of your enemy is your friend … sometimes. Farmers the world over dread an outbreak of the cereal cyst nematode (Heterodera avenae). Under the right conditions, it’ll colonize wheat, oats, barley, and other profitable crops. Once inside, the nematode has a nasty habit of knotting up roots, which may ultimately kill the host. Economically, the consequences are often dire: In 1988, this organism single-handedly caused wheat productivity in Pakistan to drop by an estimated 15 to 20 percent.

Yet in our war against the menace, we’ve found an unlikely ally. Dactylaria thaumasia is a parasitic fungi that severely weakens nemotodes, putting a check on their destructive talents. Hence, as a precautionary measure, many crop-growers now plant the fungus directly into their soil.  


This is another set of cascading parasitic relationships. From the onset, this bacterium stacks the deck in its favor. Wolbachia is a genus of microscopic marauders that plagues female wasps, which inject their larvae into young botflies (themselves parasitic). The bacteria arrest the wasp’s ability to produce male offspring. By making sure that wasp populations are kept disproportionately female-heavy, Wolbachia is able to maximize the number of larvae it can infect.

Original image
25 Benefits of Adopting a Rescue Dog
Original image

According to the ASPCA, 3.3 million dogs enter shelters each year in the United States. Although that number has gone down since 2011 (from 3.9 million) there are still millions of dogs waiting in shelters for a forever home. October is Adopt a Shelter Dog Month; here are 25 benefits of adopting a shelter dog.

Original image
Brooklyn Museum, Charles Edwin Wilbour Fund, 37.406E
New Smithsonian Exhibit Explains Why Felines Were the Cat's Meow in Ancient Egypt
Original image
Brooklyn Museum, Charles Edwin Wilbour Fund, 37.406E

From bi-coastal cat cafes to celebrity pets like Lil Bub, felines are currently enjoying a peak moment in popular culture. That’s part of the reason why curators at the Smithsonian’s Arthur M. Sackler Gallery—which will re-open to visitors on Saturday, October 14, following a 3-month closure—decided to dedicate a new exhibition to ancient Egypt’s relationship with the animals.

Divine Felines: Cats of Ancient Egypt” looks at the cultural and religious importance of cats, which the Egyptians appreciated long before YouTube was a thing and #caturday was a hashtag. It's based on a traveling exhibition that began at the Brooklyn Museum in New York City. On view until January 15, 2018, it's one of several exhibits that will kick off the grand reopening of the Smithsonian’s Freer and Sackler galleries, the conjoined national museums of Asian and Middle Eastern Art.

The Freer has been closed since January 2016 for major renovations, and the Sackler since July 2016 for minor ones. The upgraded institutions will make their public debut on October 14, and be feted by a free two-day festival on the National Mall.

Featuring 80 artworks and relics, ranging from figurines of leonine deities to the tiny coffins of beloved pets, "Divine Felines" even has a cat mummy on loan from the Smithsonian’s National Museum of Natural History. These objects span from the Middle Kingdom (2008 to 1630 BCE) to the Byzantine period (395 to 642 CE).

An ancient Egyptian metal weight shaped like a cat, dating back to 305 to 30 BCE, on view at the Smithsonian’s Arthur M. Sackler Gallery
Weight in Form of a Cat, 305 to 30 BCE, Bronze, silver, lead
Brooklyn Museum, Charles Edwin Wilbour Fund, 36.114

The term “cat” is used loosely, as the Egyptians celebrated domestic mousers and fearsome predators alike.

“The Egyptians were close observers of nature, so they were observing cat behaviors,” Antonietta Catanzariti, the exhibition's in-house curator, tells Mental Floss. “They noticed that cats and lions— in general, felines—have aggressive and protective aspects, so they associated those attributes to deities.”

The ancient Egyptians viewed their gods as humans, animals, or mixed forms. Several of these pantheon members were both associated with and depicted as cats, including Bastet, the goddess of motherhood, fertility, and protection; and Sakhmet, the goddess of war and—when appeased—healing. She typically has a lion head, but in some myths she appears as a pacified cat.

A limestone sculptor's model of a walking lion, on display at the Smithsonian's Arthur M. Sackler Gallery.
Sculptor's Model of a Walking Lion, ca. 664 to 630 BCE, limestone
Brooklyn Museum, Charles Edwin Wilbour Fund, 33.190

While Bastet was a nurturer, Sakhmet—whose name means “The Powerful One”—could use her mighty force to either slay or safeguard humanity. These characterizations are typical of the ancient Egyptian worldview, which perceived the universe in dualistic terms. “There’s always a positive and a negative,” Catanzariti explains.

Contrary to popular belief, however, ancient Egyptians did not view cats themselves as gods. “The goddess Sakhmet does have the features as a lion, or in some cases as a cat, but that doesn’t mean that the Egyptians were worshipping cats or lions,” Catanzariti says. Instead, they were simply noting and admiring her feline traits. This practice, to an extent, also extended to royalty. Kings were associated with lions and other large cats, as they were the powerful protectors of ancient Egypt’s borders.

These myriad associations prompted Egyptians to adorn palaces, temples, protective amulets, ceremonial vessels, and accessories with cat images. Depending on their context, these renderings symbolized everything from protection and power to beauty and sexuality. A king’s throne might have a lion-shaped support, for example, whereas a woman’s cosmetics case might be emblazoned with a cat-headed female goddess of motherhood and fertility.

An ancient Egyptian figurine of a standing lion-headed goddess, on display at the Smithsonian's Arthur M. Sackler Gallery.
Figurine of a Standing Lion-Headed Goddess, 664 to 630 BCE, Faience
Brooklyn Museum, Charles Edwin Wilbour Fund, 37.943E

While cats were linked with heavenly figures and kings, they were also popular domestic pets. Their ability to catch vermin made them an important addition to households, and owners loved and anthropomorphized their pets just like we do today.

Egyptians often named, or nicknamed, their children after animals; Miit (cat) was a popular moniker for girls. It's said that entire households shaved their eyebrows in mourning if a house cat died a natural death. Some also believe that cats received special legal protection. (Not all cats were this lucky, however, as some temples bred kittens specifically to offer their mummified forms to the gods.) If a favorite cat died, the Egyptians would bury them in special decorated coffins, containers, and boxes. King Tutankhamen, for example, had a stone sarcophagus constructed just for his pet feline.

An ancient Egyptian bronze cat head adorned with gold jewelry, on display at the Smithsonian's Arthur M. Sackler Gallery.
Cat's Head, 30 BCE. to third century CE, bronze, gold
Brooklyn Museum, Charles Edwin Wilbour Fund, 36.114

“Divine Felines” breaks down these facts, and more, into five thematic sections, including “Cats and Kings"; “Cats and Gods”; “Cats and Death”; “Cats and Protection”; and “Dogs as Guardians and Hunters.” Yes, there’s also an exhibition section for dog lovers—“a small one,” Catanzariti laughs, that explains why canines were associated with figures like Anubis, the jackal-headed god of mummification and the afterlife.

Did the ancient Egyptians prefer cats to dogs? “I would say that both of them had different roles,” Catanzariti says, as dogs were valued as hunters, scavengers, and guards. “They were appreciated in different ways for their ability to protect or be useful for the Egyptian culture.” In this way, "Divine Felines" is targeted to ailurophiles and canophiliacs alike, even if it's packaged with pointed ears and whiskers.

An ancient Egyptian cat coffin, on display at the Smithsonian's Arthur M. Sackler Gallery.
Coffin for a Cat, 664 to 332 BCE, or later, Wood, gesso, paint, animal remains
Brooklyn Museum, Charles Edwin Wilbour Fund, 37.1944Ea-b


More from mental floss studios