Fungal Parasites and Zombie Ants

Val shared this video in her E&EB 122 section last year.  It shows a fungus, specifically a Cordycep, that infects ants ant come into contact with it.  Once it infects an ant, it will begin to grow, and kill its host in a few days (Hughes et al 2011).  Then, a stalk will emerge from the ant's head and release new spores (as seen in the video, and also this picture).

(National Geographic)

One of the more remarkable things about fungus (or rather, these funguses, since what was thought to be one species turns out to be at least four) is that it first causes the ants to find a way to a place that is well suited for releasing the spores, such as a certain height in the rainforest canopy.  The ant then latches on to the leave, anchoring itself with a "death grip" so that it stays fixed.

This isn't rare parasite behavior.  This kind host manipulation is found in may species, including insects,  mice, snails, and many others.  It can even affect humans (serious links one and two; silly link).  What's amazing is how long this particular fungus seems to have been around: 48 million years.  It's also pretty neat how they discovered this.  Obviously, behavior can be very difficult to study from the fossil record, and fungi don't lend to good fossils either.  But the ant's death grip actually leaves a very distinctive mark on leaves, which are often preserved well.  The researchers looked at leaf fossils, and found evidence of this behavior 48 mya, making it the first known example of host behavioral manipulation...as well as something that looks like it's straight out of a science fiction movie.