Last year I wrote about the emerald cockroach wasp, Ampulex compressa, which injects venom into cockroaches to turn them into zombie hosts for their parasitic offspring. (More posts on Ampulex here.) The scientists I wrote about have been trying to figure out what exactly the venom does to the nervous system of their victims, and they've discovered that it interferes with a neurotransmitter called octopamine. New Scientist has an update. And they also have a link to a YouTube video that offers more than you may want to see of this awesome parasitic manipulation.
Ampulex and Cockroach is such a great story!
We had some guesses about the neurophysiological mechanism but now Lior Rosenberg did a great job in this paper (http://jeb.biologists.org/cgi/reprint/210/24/4411) to show not only that Octopamine has this de-zombie-ing effect but also which other neuromodulators do not affect the stung cockroach.
And mentioning evolution in action and parasitic systems, a paper in Nature reports an adaptive arms-race frozen in mud! (http://www.nature.com/nature/journal/v450/n7171/full/nature06291.html)