Parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s appear frequently in biology-inspired fiction from ancient times onwards, with a flowering in the nineteenth century. These include intentionally disgusting alien monsters in
science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...
vampire
A vampire is a mythical creature that subsists by feeding on the vital essence (generally in the form of blood) of the living. In European folklore, vampires are undead creatures that often visited loved ones and caused mischief or deat ...
are found in books and films. Some fictional parasites, like
Count Dracula
Count Dracula () is the title character of Bram Stoker's 1897 gothic horror novel ''Dracula''. He is considered to be both the prototypical and the archetypal vampire in subsequent works of fiction. Aspects of the character are believed by some ...
and ''
Alien
Alien primarily refers to:
* Alien (law), a person in a country who is not a national of that country
** Enemy alien, the above in times of war
* Extraterrestrial life, life which does not originate from Earth
** Specifically, intelligent extrater ...
''s
Xenomorph
The Alien (also known as a ''Xenomorph XX121'' or ''Internecivus raptus'', or simply a xenomorph)Alien: The Weyland-Yutani Report is a fictional parasitoid, endoparasitoid Extraterrestrials in fiction, extraterrestrial species that serves as the ...
s, have become well known in their own right.
Context
In
evolutionary biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes ( natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life ...
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is
adapted
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
structurally to this way of life. The entomologist
E. O. Wilson
Edward Osborne Wilson (June 10, 1929 – December 26, 2021) was an American biologist, naturalist, entomologist and writer. According to David Attenborough, Wilson was the world's leading expert in his specialty of myrmecology, the study of an ...
has characterised parasites as "predators that eat prey in units of less than one". According to the immunologist John Playfair, the term 'parasite' is distinctly derogatory in common usage, where a parasite is "a sponger, a lazy profiteer, a drain on society". Playfair is comparing the popular usage to a biologist's view of parasitism, which he calls (heading the same page) "an ancient and respectable view of life". The idea is however much older. In ancient Rome, the ''parasitus'' was an accepted role in Roman society, in which a person could live off the hospitality of others, in return for "flattery, simple services, and a willingness to endure humiliation".
Motifs
Nineteenth century novels
Parasitism featured repeatedly as a literary motif in the nineteenth century, though the mechanisms, biological or otherwise, are not always described in detail. For example, the eponymous Beetle in '' The Beetle'' by Richard Marsh, 1897, is parasitic and symbolically castrates the human protagonist.Bram Stoker's 1897 '' Dracula'' starts out as an apparently human host, welcoming guests to his home, before revealing his parasitic
vampire
A vampire is a mythical creature that subsists by feeding on the vital essence (generally in the form of blood) of the living. In European folklore, vampires are undead creatures that often visited loved ones and caused mischief or deat ...
nature.
Conan Doyle
Sir Arthur Ignatius Conan Doyle (22 May 1859 – 7 July 1930) was a British writer and physician. He created the character Sherlock Holmes in 1887 for ''A Study in Scarlet'', the first of four novels and fifty-six short stories about Hol ...
's Parasite, in his 1894 book '' The Parasite'', makes use of a form of mind control similar to the
mesmerism
Animal magnetism, also known as mesmerism, was a protoscientific theory developed by German doctor Franz Mesmer in the 18th century in relation to what he claimed to be an invisible natural force (''Lebensmagnetismus'') possessed by all liv ...
of the
Victorian era
In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardia ...
science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...
as distasteful, in contrast to (mutualistic) symbiosis, and sometimes horrible. Practical uses can be made of them, but humans who do so may be destroyed by them. For example, Mira Grant's 2013 novel ''
Parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
'' envisages a world where people's
immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splint ...
s are maintained by
genetically engineered
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
tapeworm
Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cesto ...
s. They form readily understood characters, since, as Gary Westfahl explains, parasites need to exploit their hosts to survive and reproduce.
The social anthropologist Marika Moisseeff argues that Hollywood science fiction favours insects as
villain
A villain (also known as a " black hat" or "bad guy"; the feminine form is villainess) is a stock character, whether based on a historical narrative or one of literary fiction. ''Random House Unabridged Dictionary'' defines such a character ...
characters because of their parasitism and their swarming behaviour. Such films, she continues, depict the war of culture and nature as "an unending combat between humanity and insect-like extraterrestrial species that tend to parasitize human beings in order to reproduce."
Range
The range of accounts of fictional parasites and the media used to describe them have greatly increased since the nineteenth century, spanning among other things literary novels, science fiction novels and films, horror films, and
video game
Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This fee ...
s. The table illustrates the variety of themes and approaches that have become possible.
Fiction and reality
Kyle Munkittrick, on the ''Discover'' magazine website, writes that the great majority of aliens, far from being as strange as possible, are humanoid. Ben Guarino, in ''
The Washington Post
''The Washington Post'' (also known as the ''Post'' and, informally, ''WaPo'') is an American daily newspaper published in Washington, D.C. It is the most widely circulated newspaper within the Washington metropolitan area and has a large nati ...
'', observes that despite all the "cinematic aliens' gravid grotesquerie", earthly parasites have more horrible ways of life. Guarino cites parasitic wasps that lay their eggs inside living caterpillars, inspiring
A. E. Van Vogt
Alfred Elton van Vogt ( ; April 26, 1912 – January 26, 2000) was a Canadian-born American science fiction author. His fragmented, bizarre narrative style influenced later science fiction writers, notably Philip K. Dick. He was one of the ...
The Puppet Masters
''The Puppet Masters'' is a 1951 science fiction novel by American writer Robert A. Heinlein, in which American secret agents battle parasitic invaders from outer space. It was originally serialized in ''Galaxy Science Fiction'' (September, Oc ...
'', and Ridley Scott's 1979 film ''Alien''. The eponymous Alien has a "dramatic" life-cycle. Giant eggs hatch into face-huggers that grasp the host's mouth, forcing him to swallow an embryo. It rapidly grows in his intestines, soon afterwards erupting from his chest and growing into a gigantic predatory animal resembling an insect. Guarino cites the parasitologist Michael J. Smout as saying that the "massive changes" are feasible, giving the example of flatworms that transform from an egg to a tadpole-like form to an infective worm. The biologist Claude dePamphilis agrees, too, that parasites can acquire
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
s from their hosts, giving as example a
broomrape
''Orobanche'', commonly known as broomrape, is a genus of over 200 species of small parasitic herbaceous plants, mostly native to the temperate Northern Hemisphere. It is the type genus of the broomrape family Orobanchaceae.
Description
Broom ...
plant that had taken up genes from its host on 52 occasions, having thoroughly overcome the host plant's defences. They suggest further themes for future science fiction films, including emerald jewel wasps that turn
cockroach
Cockroaches (or roaches) are a Paraphyly, paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are we ...
es into subservient puppets, able to crawl but unable to act independently; or the barnacle-like crustaceans that castrate their crab hosts, or grow into their brains, altering their behaviour to care for the young barnacles. All the same, a 2013 poll of scientists and engineers by ''
Popular Mechanics
''Popular Mechanics'' (sometimes PM or PopMech) is a magazine of popular science and technology, featuring automotive, home, outdoor, electronics, science, do-it-yourself, and technology topics. Military topics, aviation and transportation o ...
'' magazine revealed that the parasite-based science fiction films ''
The War of the Worlds
''The War of the Worlds'' is a science fiction novel by English author H. G. Wells, first serialised in 1897 by ''Pearson's Magazine'' in the UK and by ''Cosmopolitan (magazine), Cosmopolitan'' magazine in the US. The novel's first appear ...
'' (
Byron Haskin
Byron Conrad Haskin (April 22, 1899 – April 16, 1984) was an American film and television director, special effects creator and cinematographer. He is best known for directing '' The War of the Worlds'' (1953), one of many films where he ...
, 1953) and ''Alien'' were among their top ten favourites.
Types of parasite
Several types of parasite, corresponding more or less accurately to some of those known in biology, are found in literature. These include haematophagic parasites (fictional vampires), parasitoids, behaviour-altering parasites, brood parasites, parasitic castrators, and trophically transmitted parasites, as detailed below.
Haematophagic parasite
In ancient times, myths of blood-drinking demons were widespread, including
Lilith
Lilith ( ; he, לִילִית, Līlīṯ) is a female figure in Mesopotamian and Judaic mythology, alternatively the first wife of Adam and supposedly the primordial she-demon. Lilith is cited as having been "banished" from the Garden of Ed ...
who feasted on the blood of babies.
Fictional
vampire
A vampire is a mythical creature that subsists by feeding on the vital essence (generally in the form of blood) of the living. In European folklore, vampires are undead creatures that often visited loved ones and caused mischief or deat ...
s— haematophagic parasites—began in the modern era with
Count Dracula
Count Dracula () is the title character of Bram Stoker's 1897 gothic horror novel ''Dracula''. He is considered to be both the prototypical and the archetypal vampire in subsequent works of fiction. Aspects of the character are believed by some ...
, the
title character
The title character in a narrative work is one who is named or referred to in the title of the work. In a performed work such as a play or film, the performer who plays the title character is said to have the title role of the piece. The title of ...
gothic horror
Gothic fiction, sometimes called Gothic horror in the 20th century, is a loose literary aesthetic of fear and haunting. The name is a reference to Gothic architecture of the European Middle Ages, which was characteristic of the settings of ea ...
novel '' Dracula'', and have since appeared in many books and films ranging from horror to science fiction. Along with the shift in genres went a diversification of life-forms and life-cycles, including blood-drinking plants like the "strange orchid" in ''The Thing from Another World'', aliens like
The War of the Worlds
''The War of the Worlds'' is a science fiction novel by English author H. G. Wells, first serialised in 1897 by ''Pearson's Magazine'' in the UK and by ''Cosmopolitan (magazine), Cosmopolitan'' magazine in the US. The novel's first appear ...
Xenomorph
The Alien (also known as a ''Xenomorph XX121'' or ''Internecivus raptus'', or simply a xenomorph)Alien: The Weyland-Yutani Report is a fictional parasitoid, endoparasitoid Extraterrestrials in fiction, extraterrestrial species that serves as the ...
in ''
Alien
Alien primarily refers to:
* Alien (law), a person in a country who is not a national of that country
** Enemy alien, the above in times of war
* Extraterrestrial life, life which does not originate from Earth
** Specifically, intelligent extrater ...
'' is a parasitoid, inevitably fatal to its human host. It has a life-cycle stage that grows inside the person's body; when mature, the predatory adult Xenomorph bursts out, killing the host. This behaviour was inspired by
parasitoid wasp
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causin ...
s which have just such a life-cycle.
The molecular biologist Alex Sercel compares Xenomorph biology to that of parasitoid wasps and nematomorph worms, arguing that there is a close match. Sercel notes that the way the Xenomorph grasps a human's face to implant its embryo is comparable to the way a parasitoid wasp lays its eggs in a living host. He compares the Xenomorph life cycle to that of the nematomorph ''
Paragordius tricuspidatus
''Paragordius tricuspidatus'' belongs to the phylum Nematomorpha, and is known for manipulating the behavior of its host, the cricket ''Nemobius sylvestris''. In its larval stage, the worm is microscopic, but grows into a large worm () inside i ...
'', which grows to fill its host's body cavity before bursting out and killing it.
The marine biologist Alistair Dove writes that there are multiple parallels between Xenomorphs and parasitoids, though there are in his view more disturbing life cycles in real biology. He identifies parallels include the placing of an embryo in the host; its growth in the host; the resulting death of the host; and alternating generations, as in the Digenea (trematodes).
Behaviour-altering parasite
Mind-controlling parasites feature in twentieth century science fiction. In
Robert A. Heinlein
Robert Anson Heinlein (; July 7, 1907 – May 8, 1988) was an American science fiction author, aeronautical engineer, and naval officer. Sometimes called the "dean of science fiction writers", he was among the first to emphasize scientific accu ...
's 1951 ''
The Puppet Masters
''The Puppet Masters'' is a 1951 science fiction novel by American writer Robert A. Heinlein, in which American secret agents battle parasitic invaders from outer space. It was originally serialized in ''Galaxy Science Fiction'' (September, Oc ...
Toxoplasma gondii
''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...
'', which causes infected mice to become unafraid of cats. This makes them easier to catch and consume and, once an infected mouse has been eaten, the parasite will then infect the cat, its
definitive host
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' ( symbiont). The guest is typically provided with nourishment and shelter. Examples include ...
, in which it can reproduce sexually. The
Goa'uld
The mythology of the ''Stargate'' franchise is the historical backstory of the ''Stargate'' premise, which centers around xeno-mythology as experienced by humans during episodic contact. In the fictional universe of the franchise, the people of ...
in ''
Stargate SG-1
''Stargate SG-1'' (often stylized in all caps, or abbreviated ''SG-1'') is a military science fiction adventure television series within Metro-Goldwyn-Mayer's ''Stargate'' franchise. The show, created by Brad Wright and Jonathan Glassner, ...
'' enters through the host's neck and coils around the host's spine, assuming control.
The Slug/Squid alien in '' The Hidden'' similarly enters via the host's mouth before taking over its body.
Brood parasite
Brood parasitism
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ow ...
is not a common theme in fiction. An early example was
John Wyndham
John Wyndham Parkes Lucas Beynon Harris (; 10 July 1903 – 11 March 1969) was an English science fiction writer best known for his works published under the pen name John Wyndham, although he also used other combinations of his names ...
's 1957 novel ''
The Midwich Cuckoos
''The Midwich Cuckoos'' is a 1957 science fiction novel written by the English author John Wyndham. It tells the tale of an English village in which the women become pregnant by brood parasitic aliens. The book has been praised by many critic ...
'', which sees the women of an English village give birth to and then bring up a group of alien children. The aliens are telepathic, and intend to take over the world. In nature, brood parasitism occurs in birds such as the
European cuckoo
The common cuckoo (''Cuculus canorus'') is a member of the cuckoo order of birds, Cuculiformes, which includes the roadrunners, the anis and the coucals.
This species is a widespread summer migrant to Europe and Asia, and winters in Africa. I ...
, which lay their eggs in the nests of their hosts. The young cuckoos hatch quickly and eject the host's eggs or chicks; the host parents then feed the young cuckoos as if they were their own offspring, until they fledge. As a plot device, this allows aliens and humans to interact closely. A somewhat similar approach is taken in
Octavia E. Butler
Octavia Estelle Butler (June 22, 1947 – February 24, 2006) was an American science fiction author and a multiple recipient of the Hugo and Nebula awards. In 1995, Butler became the first science-fiction writer to receive a MacArthur Fellowshi ...
's 1987–1989 ''
Lilith's Brood
''Lilith's Brood'' is a collection of three works by Octavia E. Butler. The three volumes of this science fiction series (''Dawn'', ''Adulthood Rites'', and ''Imago'') were previously collected in the now out-of-print volume ''Xenogenesis''. T ...
'', but the offspring born to the human mother there is an alien-human hybrid rather than simply an alien.
Parasitic castrator
Parasitic castration
Parasitic castration is the strategy, by a parasite, of blocking reproduction by its host, completely or in part, to its own benefit. This is one of six major strategies within parasitism.
Evolutionary strategy
The parasitic castration strateg ...
is found in nature in greatly reduced parasites that feed on the gonads of their crab hosts, making use of the energy that would have gone into reproduction. It is seen in fiction in Philip Fracassi's 2017 horror novella ''Sacculina'', named for a genus of barnacle-like crustaceans with this lifestyle. It tells the tale of a chartered fishing boat, far from home, that is overrun by parasites from the deep. The horror publishing house Gehenna and Hinnom state that "such a vile and frightening name fits perfectly as the title of this novella."
Trophically-transmitted parasite
The genetically engineered tapeworm in Mira Grant's novel ''Parasite'', and the talking tapeworm in Irvine Welsh's novel ''Filth'', are fictional versions of conventional intestinal parasites.
Tapeworms
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of ...
have complex life-cycles, often involving two or more hosts of different species, and are transmitted as the eggs are passed in
faeces
Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...
and eaten by another host, only for the host to be eaten, passing the parasite on to the predator. The unattractive lifecycle allows the novelists to exploit their readers' emotional reactions to the parasites. The parasite in Welsh's novel has been described as a "kind of sinister but strangely comic element".
Genetics in fiction
Aspects of genetics including mutation, hybridisation, cloning, genetic engineering, and eugenics have appeared in fiction since the 19th century.
Genetics is a young science, having started in 1900 with the rediscovery of Gregor Mendel's stud ...