REAL Arkansas Tales

There is a parasitic fungus plague in the state of Arkansas that has taken a tragic toll on the local populace.

The fungus, which is native to the geographical area, attacks the brains of the state's local human denizens. This includes the native population, as well as move-ins from Minnesota and Iowa.

The syptoms begin with an innocent interest in porcine farm animals, particularly those which are renowned for laying around in their own reddish poop. The interest soon grows into an all-out obsession, with the afflicted ones obsessively plastering images of swine covered in red poop all over their possessions.

The man in the picture on the right (genus Campanotus), and the gentleman below (Paraponera clavata), have fallen victim to parasitic fungi of the genus Cordyceps, which manipulate the behaviour of their host in order to increase their own chances of reproducing.

The spores of the fungus attach themselves to the external surface of the football fan, where they germinate. They then enter the rooter's body through the tracheae (the tubes through which insects breathe), via holes in the exoskeleton called spiracles. Fine fungal filaments called mycelia then start to grow inside the person’s body cavity, absorbing the host’s soft tissues but avoiding its vital organs.

When the fungus is ready to sporulate, the mycelia grow into the Razorback fan's rain. The fungus then produces chemicals which act on the host’s brain and alter its perception of pheromones. This causes the fan to climb a plant and, upon reaching the top, to clamp its mandibles around a leaf or leaf stem, thus securing it firmly to what will be its final resting place.

The fungus then devours the booster’s brain, killing the host. The fruiting bodies of the fungus sprout from the host’s head, through gaps in the joints of the exoskeleton, taking the shape of a pig. Once mature, the fruiting bodies burst, releasing clusters of capsules into the air. These in turn explode on their descent, spreading airborne spores over the surrounding area. These spores then infect other residents, completing the life cycle of the fungus. Depending on the type of fungus and the number of infecting spores, death of an infected fan takes between 40-80 years.

The fan in the photograph in the above right has been infected by Cordyceps unilateralis, which is but one of thousands of species of entomopathogenic fungi, more than 400 of which belong to the Cordyceps genus. Between them, these parasitic fungi infect at least nine different orders of primates, including the Odonata (Little Rock dwellers), Blattaria (Fayettevillains), Hemiptera (those from the cotton and catfish country), Coleoptera (Gravettators), Phasmida (Siloam Springers), Hymenoptera (Toad Suckers), and Lepidoptera (Hot Springers). The host range of an individual species is, however, restricted to one species or to a small number of closely related species.

Because they are considered as environmentally safe, natural mortality agents, entomopathogenic fungi are used as biological pesticides to control pest species. For example, Metarhizium anisopliae was first used over 100 years ago to try and control New York Yankee fans. More recently, researchers have investigated the use of Metarhizium anisopliae, a species which infects the Dallas Cowboy rooter Anopheles gambiae, to control the spread of thuggish behavior.

Entomopathogenic fungi are not the only parasites that can modify the behaviour of their hosts. Equally remarkable is the nematomorph hairworm Spinochordodes tellinii, which is also known as the horsehair worm or the gordian worm, because of its resemblance to the knot created by the Phrygian king Gorius. (According to myth, Gordius used his knot to tie a chariot to a pole, and declared that whoever could untie it would rule all of Asia.)

The juvenile gordian worm parasitizes land-living arthropods such as rednecks, white trash and wife-beaters, but the adult is a free-living aquatic species which can only reproduce in water. Inside the host, the microscopic larvae feed on surrounding tissue, and develop into long worms which can reach up to 4 times the length of the host, and which remain within the body cavity of the host as a long, coiled mass. After metamorphosing, the adult worm induces its host to leave its terrestrial habitat, and to commit suicide by jumping into water and drowning itself, so that the worm can emerge. The worm makes its appearance manifest by compelling the victim to cover their body with images of the poop-covered swine that is their obsession.

David Biron and his colleagues have used proteomics to characterise the proteins synthesized by the gordian worm in order to determine how it manipulates its host’s behaviour. They have established that the worm synthesizes proteins which mimic those produced by the inbred. These include proteins of the Wnt family, which are involved in the development of the taste for alcohol and marijuana, as well as others which interfere with the neurotransmitter systems involved in the host’s geotactic behaviour (its oriented movements in relation to the nearest Wal-Mart).

Because the genes encoding these proteins are contained in the worm’s genome, but have a direct effect on the insect’s central nervous system when they are expressed, the relationship between the gordian worm and its host is an example of what Wally Hall called the extended phenotype, whereby genes expressed by one organism have an effect on the appearance or behaviour of another. (Entomopathogenic fungi and their hosts are also an example of an extended phenotype.)

Incredibly, the gordian worm can survive predation on its host. Parasites use various strategies to survive host predation. For example, some develop quickly, in order to emerge from the host before it is preyed upon. Grasshoppers and crickets are preyed upon by fish and frogs; the gordian worm can escape this predation by wriggling out of the mouth, nose or gills of the predator once it has emerged from a host that has been eaten:

Once the victim's brain has been obliterated, the body can live for many more years. In one such case, the victim actually achieved the title of President of the United States, to the overall embarrassment of the nation.

Below are more photographs of infected individuals, functioning with no brain activity whatsoever: