Pseudacteon Flies

This post is a little late, as it concerns a topic that we discussed last week, but it's another really interesting example of how a parasite can alter host behavior. Female Pseudacteon flies quickly inject an egg into the neck region of an ant through a rapid attack. The larva moves into the head cavity of the ant, where it eventually eats the brain of the ant (and therefore kills it). The head of the ant falls off, and the organism continues to develop inside the detached head. Once fully developed, the organism leaves the head as an adult fly.

http://www.biocontrol.entomology.cornell.edu/parasitoids/pseudacteon.html