PARASITISM AND SYMBIOSIS

   Parasitism and symbiosis are Nature's extreme forms of commensalism (physical association). A parasitic species promotes its own interests entirely to the detriment of the other; symbiosis refers to the much less common state in which both organisms obtain some benefit from the association.Imaginary parasites of human beings are featured in many effective sf HORROR stories, often linked to the idea of vampirism (although classical vampires might better be regarded as predators than asparasites). Stories dealing with LIFE ON OTHER WORLDS often feature parasites which are exaggerated versions of earthly creatures. Those insects which lay their eggs in living hosts are popular models; they feature in A.E. VAN VOGT's "Discord in Scarlet" (1939; incorporated in The Voyage of the Space Beagle, fixup 1950) and the film ALIEN (1979) and itssequels; the closely related notion of the mother killed by her internal young appears in Philip Jose FARMER's THE LOVERS (1952; exp 1961) and Gardner DOZOIS's STRANGERS (1978). Parasites leeching the "vital energy"of human beings are commonplace; when the parasites are internal rather than external this often involves the will of the victim being usurped, thus referring metaphorically to demonic possession as well as to vampirism. Early examples of this kind of story include J. Maclaren COBBAN's Master of His Fate (1890) and Arthur Conan DOYLE's The Parasite(1895); the classic PULP-MAGAZINE sf extrapolations are Eric Frank RUSSELL's Sinister Barrier (1939; 1943; rev 1948) and Robert A. HEINLEIN's The Puppet Masters (1951). Other stories in the same vein are Russell's "Vampire from the Void" (1939), Farmer's "Strange Compulsion" (1953; vt "The Captain's Daughter"), Frank R. CRISP's The Ape of London (1959), Robert SILVERBERG's "Passengers" (1968), Colin WILSON's The Mind Parasites (1967) and The Space Vampires (1976), David CRONENBERG's film The PARASITE MURDERS (1974) and Damon KNIGHT's CV (1985).This frequent movement of the notion of parasitism from the context of the mundane to the quasisupernatural is in keeping with sf's habitual treatment of biological themes (BIOLOGY). In concert with general trends relating to ALIENS there was a dramatic change of emphasis in post-WWII stories, in which apparently parasitic relationships are often revealed to be in fact symbiotic. Some stories are conscious ideological replies to earlier works - Ted WHITE's By Furies Possessed (1970), which attacks the implicitxenophobia of The Puppet Masters, is a notable example. The concept of symbiosis had earlier been used in some ecological puzzle stories (ECOLOGY), notably Eric Frank Russell's "Symbiotica" (1943) and an ironicstory of defensive biological warfare, "Symbiosis" (1947) by Will F. Jenkins (Murray LEINSTER), but the quasisupernatural connotations iteventually took on were decisively opposed to metaphors of vampirism and possession. It became a central notion of the "ecological mysticism" displayed in such works as Sydney J. VAN SCYOC's trilogy Daughters of the Sunstone (1982-4; omni 1985). Explicit religious imagery comes to the forein such stories of human/alien symbiosis as Clifford D. SIMAK's Time and Again (1951; vt First He Died), Bob SHAW's Palace of Eternity (1969) andNicholas Yermakov's trilogy begun with The Last Communion (1981). Post-WWII stories in which human and alien minds share a brain usually see such relationships as potentially symbiotic; examples include Hal CLEMENT's Needle (1950), Brian M. STABLEFORD's Halcyon Drift series(1972-5), Roger ZELAZNY's Doorways in the Sand (1976) and F. Paul WILSON's Healer (1976). Even Christopher EVANS's bleak mind-parasite story The Insider (1981) is sympathetic to the parasitic consciousness. The more ambivalent view of human/alien commensalism adopted in Octavia E. BUTLER's Clay's Ark (1984) and related works and in the first part of Dan SIMMONS'sHYPERION (1989) cleverly exploits and undercuts this modern sensibility.This area of speculation is perhaps the most obvious example in sf of the utility of biological notions as metaphysical metaphors (METAPHYSICS), and of the way that such metaphorical usage dominates theexpression of biological notions in sf.

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   See also: HIVE-MINDS; PARANOIA; SUPERNATURAL CREATURES.