Spooky Story

     Once infected with the larval egg of H. argyraphaga, the Plesiometa argyra will continue to develop and resume its characteristic orb-web building activities, oblivious to its ensuing fate. When the larva erupts from its egg --now considered to be a first instar-- it makes a variety of feeding scars in which it sucks the hemolymph from the spider. Due to the ecdysozoan heritage of this wasp species, molting occurs. With each successive molting, the next, more developed, instar is produced. So after a period ranging from 58  to 69 hours, the first instar molts and becomes the second instar. Besides the obvious growth difference between the first and second instar, the behaviors exhibited by each is also markedly different (Eberhard, 2000). When the the second instar is developed, things start to get a bit odd.
    Preparing for its cocoon formation, the H. argyraphaga utilizes its prey's web-building capabilities. The second instar releases what has been proposed to be a specific chemical which manipulates the spiders web-building routine. Plesiometa argyra begins to repeat a simple web construction procedure of laying down radial lines over and over again, building what has come to be known as a "cocoon web" (Eberhard, 2001). Observations conclude that this behavior is quite irregular; it seems this web design exists solely to increase the chances of survival of the wasp species. Upon completion of the cocoon web, the spider dies; in one observation, cardiac arrest was the cause.  Finally, the second instar molts one last time into the third and final instar whereby it proceeds to suck the P. argyra dry of its hemolymph and discards of its exoskeleton. With the highly-reinforced, specialized web freshly made, the final instar forms its cocoon (Eberhard, 2000). Ah, the power of mind control!

Created by and courtesy of: rocko fry

To check out other cases of mind control by organisms, visit this website. In fact, a well-known parasitic Apicomplexan exists as Toxoplasma gondii. Another interesting organism is the Anisakis simplex, a marine parasite with a complex life cycle.

Cool facts anyone?