17. The modern and ancestral natural hosts - Speculations about the alien species (Movies: Alien)
Description
This article is from the Alien Movies FAQ, by Darryll Hobsonand Eelko de Vos E.W.C.deVos@TWI.TUDelft.NL with numerous contributions by others.
17. The modern and ancestral natural hosts - Speculations about the alien species (Movies: Alien)
The modern species' reproductive cycle is problematic because it
displays a dependence upon the death of a host for the reproduction of a
each organism. A host which survived nymph emergence might favor the
development of this lifestyle. Such a host would have to withstand the
damage incurred in emergence, and be able to survive further rounds of
implantation, gestation and emergence. Alternatively, ancestral forms of
the organism might have used a less injurious host-emergence strategy. If
instead of creating new exits, the nymphs emerged via the orifice through
which they were implanted, the chance of the host surviving would
increase dramatically. Possibly, ancestral organisms used such a strategy.
Also, a host with thick exterior armor would make creation of new exits
difficult. In any case, a large organism would be better suited to surviving
the embryo development process. The parasite might be little more than a
pest for a host of sufficient size, and might even serve some symbiotic
function by feeding on exoskeletal parasites of the host after emergence.
The implantation period indicates a requirement for about 24 hours of
close contact. This is facilitated by the articulated limbs and the tail. In
modern creatures, the larval "embryopositor" appears to be composed of
soft tissue, indicating that implantation is probably directly onto the
desired internal substrate as opposed to being gained by destruction of
external tissue. In addition to other possible functions, the mouthed tongue
of the imago might function to permit sampling of the tissue contained
within a hard carapace, or might have facilitated in creating an opening in
a hard carapace specifically for use in implantation. These data suggest
that the natural host possessed a hard shell.
During the implantation phase, the host is provided with atmosphere via
specialized bellows structures on the larva, implying that the host would
be in danger of asphyxiation during the implantation process. Thus the
natural host probably has only one breathing orifice, and is at least
partially terrestrial. The parameters of the area surrounding the natural
host's breathing orifice may be estimated via observing the length of tail
available and the available span of the articulated limbs (2-3 feet for the
limbs and 4-5 feet of tail). This orifice is most likely at the end of a stalk
of indeterminate length, which might be up to a foot in diameter. The
terminus of this stalk is most likely a spheroid 1-2 feet in diameter.
The amount of oxygen provided to the host is limited by the size of
the larval bellows apparatus, and this would limit the size of a potential
host and that host's activity during implantation. Possibly the bellows size
has evolved to parallel changes in host size. The constrictive nature of the
tail would seem to suggest that the host's breathing is accomplished by
changing the volume of the stalk. Bi-directional air flow in the host might
be accomplished via the use of peristaltic waves. Since the host is likely
armored, the tail would probably not be capable of constricting the host
unless this strategy were used to inhale and exhale.
Assuming that the host would resent an attack on its sole breathing orifice
and the subsequent implantation event, temporary incapacitation of the
host would be desirable on the part of the organism. An extremely large
host might be able to detach the larva at negligible expense to its own
structure. Possibly the constrictive nature of the tail is used to immobilize
the host initially. However, an incapacitated host would be easy prey to
various other predatory creatures. It is possible that the implantation
period would not be *extremely* uncomfortable for the host, and that the
host would be capable of enduring the implantation period without
sufficient cause to successfully dislodge the parasite. In this case, the
implantation process might only diminish the host's natural breathing
capacity, requiring the supplemental air supply provided by the larva. In
such a scenario, it might be possible for multiple larvae to simultaneously
implant embryos in one host.
Emergence of the nymph seems to be triggered by moderate levels of host
activity. This might be a valid strategy if the host was preyed upon.
Moderate levels of activity would indicate that there were no predators
around and that the locale was safe for nymph emergence. Sufficiently
high level of activity might indicate flight from a predator, and a period of
inactivity might be indicative of a host's attempt to hide from a predator.
The general conclusions regarding the natural host are as follows; it is a
large terrestrial or semi-aquatic organism which breathes through an
orifice at the end of a stalk. This could be the host's head, or it could be a
specialized structure. The host is most likely armored and is possibly prey
to other predators.
Most of the above speculation regards the natural host of the pre-social
organism. The natural host of the social organism is most likely a smaller
version of the described host. Smaller hosts would occur in more abundant
numbers, and their populations might tolerate the parasitic lifestyle of
increasing numbers of organisms. In addition, it is more efficient to
capture, immobilize and maintain smaller hosts than large. It is possible
that the modern organism's penchant for creating a new emergence orifice
is a modification subsequent to the dispersal into space; on the
homeworld, the social organisms might remain capable of multiple rounds
of implantation, gestation and emergence on a single host. Some species
might retain the ability to switch from a social mode to a more primitive
non-social mode.
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