I was cleaning up my room last night, and this Orthopteran leg was beneath my desk. Aka, the leg of the same dead grasshopper we used in lab 3 weeks ago and that I placed ever so delicately outside of my friend's room when I was angry at her.
Can someone tell me how it could have happened that, when I disposed of the Orthopteran, its limbs--supposedly dead--managed to crawl their way out of the garbage and into my living space to haunt me for weeks? Remember that this was not the first time I found more Orthopteran limbs floating about. If you recall, I posted about a week ago about a tarsus I had found in my shoe. And, now this! A full leg! Am I dealing with a zombie Orthopteran?!?!??
Speaking of Zombie Orthopterans, there's a grasshopper parasite that lives inside grasshoppers and pumps a cocktail of chemicals through the hemolymph that drives the host to commit suicide by leaping into water. These hairworms trigger the grasshopper's leap of death by meddling with the central nervous system. This relationship was only discovered 7 years ago when a team of French biologists was monitoring grasshoppers that became trapped in a swimming pool on the border of a forest near Avene les Bains in southern France. Hundreds of grasshoppers arrived at the pool most summer night at the behest of the parasites.
Here's a video of the grasshopper suicide, accompanied by an "entretien" (interview) with some Frenchies who discovered this relationship. If you're really interested, I could translate it, but I'm kind of in a coffee shop right now and I lost my pair of headphones. :(
Image source: http://www.nytimes.com/2005/09/06/science/06hopp.html
If you watch the video, you see that the grasshopper sort of has a small wiggling tail before it takes the plunge, and then when it does, the tail gets longer and longer until a full hairworm frees itself from the posteriormost end of the grasshopper, leaving the grasshopper dead and the hairworm free to swim around in the freshwater.
The French research team looked more into the nature of this bizarre parasitism, and found that the hairworms secrete proteins that influence the grasshopper's CNS.This biochemical tampering appears to drive the grasshopper to water just when the hairworm is ready to reproduce. This is convenient for the hairworm, which spends most of its life eating away the innards of the grasshopper it infects, and then has the grasshopper transport it to freshwater when it is time to reproduce.
Biron et al. 2005 reports a clear linkage between the Orthopteran's frenzied water-seeking behavior and differential expression of the Orthopteran's CNS and of the hairworm's proteomes. Their proteomic analysis also demonstrated that certain protein families are expressed at key periods during the hairworm's life cycle and the manipulative process.
Though these proteins are produced by the hairworm, they seem to resemble insect-type proteins from the Wnt protein family, which the French biologists suspect were developed mimetically. The Wnt proteins synthesized in the parasite are homologous to, and play an important role in, in the development of CNS (Biron et al. 2005).
The biggest currently-standing question baffling scientists is how these aquatic creatures manage to parasitize terrestrial species. The guy from the interview, Frédéric Thomas, suspects that the minuscule aquatic larvae first infect aquatic insects, like mosquitoes, and then hide as cysts in their tissue. Then, when the adult mosquito flies away and dies, an Orthopteran may consume its dead body, unknowingly consuming the hairworm larvae. The hairworm will then "develop, eating absolutely everything not essential to keep its host alive," said Dr. Thomas. By the time the Orthopteran goes for its final swim, it is reduced to nothing but exoskeleton.
I can't wait for these zombie-making hairworms to make it on some sci-fi thriller. I'll be at the midnight premiere when it happens.
Also, my final conclusion is not that this is a zombie grasshopper parasitized by a hairworm. I think I'm just terrible at cleaning. Hopefully this will be the last report of unwelcome grasshopper parts in my living space.
References
Biron et al. 2005. Behavioural manipulation in a grasshopper harbouring hairworm: a proteomic approach. Proceedings of the Royal Society. 272(1577): 2117–2126.
"Suicide Grashoppers Parasitized By Parasite Worms." 1 September 2005. http://news.nationalgeographic.com/news/2005/09/0901_050901_wormparasite_2.html
Wade, Nicholas. "Parasitic Hairworm Charms Grasshopper Into Taking It For a Swim." New York Times. 6 September 2005. http://www.nytimes.com/2005/09/06/science/06hopp.html
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