To reproduce, parasite transforms ant into juicy red berry
January 17, 2008
"It's just crazy that something as dumb as a nematode can manipulate its host's exterior morphology and behavior in ways sufficient to convince a clever bird to facilitate transmission of the nematode," said lead author Robert Dudley, a professor of integrative biology at the University of California, Berkeley.
When the ant Cephalotes atratus is infected with a parasitic nematode, its normally black abdomen turns red, resembling the many red berries in the tropical forest canopy. According to researchers, this is a strategy concocted by nematodes to entice birds to eat the normally unpalatable ant and spread the parasite in their droppings. (Steve Yanoviak/University of Arkansas)
"This is a really great example of the kinds of complex host-parasite interactions that can co-evolve, and also of the role of serendipity in tropical biology," Dudley said.
The red berry nematode is not the only example of a parasite transforming its host. Parasitic fungi of the genus Cordyceps are known to manipulate the behavior of their ant host in order to increase their own reproductive chances. Inhaled by a passing ant, Cordyceps' spores grow inside the ant's body cavity, dissolving its soft tissues but leaving vital organs intact until ihen it comes time for the fungi to reproduce. Fungal filaments grow into the brain and effectively take control of the ant's mind, causing it to climate to the highest point of a plant and attach itself in place using its mandibles. The fungus then kills the ant sends up a fruiting body called a stroma which releases spores into the air, setting the stage for the cycle to repeat itself with another unsuspecting ant.