Iratus bug
Insect species native to the Pegasus Galaxy. Based on information gathered from the Ancient database and Atlantis expedition members' encounters with the creatures, it is believed that the iratus bug is responsible for the evolutionary development and life-absorbing urges of the Wraith. The combination of iratus and human D.N.A. brought about the Wraith form over millions of years.
Iratus bugs typically live and breed in dark, secluded caves. Hundreds, perhaps even thousands of the bugs can exist in extremely close proximity to one another, sharing large nests. They are known to exist on at least two worlds, including the planet presently classified as the Wraith homeworld. The creatures are capable of spinning and dangling from sticky, spider-like webbing, which they may use to ensnare their prey in order to feed.
The species maintains the eggs of their young in enormous sacks that dangle from the ceilings of the caves they inhabit. One sack can hold hundreds of eggs, and support the weight of a 150-pound man, without the breaking and falling to the ground. The exterior casing is thick and resilient.
An iratus is like a Wraith in that it has very fast regenerative capabilities. It can withstand several direct assaults by an Earth handgun and still maintain itself long enough to eventually attack again. It is known to assault its prey by burrowing like a tick into the neck of human flesh, wrapping its short, claw-like legs around the neck. The victim quickly loses motor control in the extremities, and soon his vital organs shut down.
The present theory is that the Wraith evolved when the Ancients seeded their world with human-form life, as they did throughout the Pegasus Galaxy. The iratus fed off the humans, and the early humanoids on their world incorporated iratus D.N.A. into their own. Dr. Carson Beckett has developed a prototype for an iratus bug retrovirus that would, in theory, strip the insect D.N.A. from a Wraith and leave only human biology.
Iodine and alcohol (poured on the soft tissue) have no effect on the creatures. However, the bugs are repelled by salt water. It is currently the only known deterrent (though this does not stop an iratus from feeding). The insect will only cease its life-sucking if the life-form it is attached to is dead.
KEY EPISODES
Thirty Eight Minutes - While investigating a Wraith world Sheppard is prey to an iratus bug, who refuses to let go until he is dead.
Conversion - Dr. Beckett and Major Lorne lead a team to retrieve eggs from a nesting ground of iratus bugs in the hopes of returning Colonel Sheppard to his fully-human makeup.
Vengeance - Sheppard's team discovers one of Michael's labs, where the hybrid is using iratus bugs for nefarious purposes.
Infection - To try and save his life, the Wraith Todd goes in search of an iratus queen to feed on him.