Scientists have found that the parasitic fungus Ophiocordyceps unilateralis has possibly been invading carpenter ants (Camponotus) for 48 million years. The parasite not only infects the ant, but it manipulates the ant’s behavior as well, influencing it to bite the underside of leaves along the veins. Once the ant finds an optimal location, the fungus grows rapidly, killing the ant and preparing it to release a new spore.
During this process, the ant leaves distinct marks, also known as “death bites,” on the leaves as they bite the veins in search of a prime spot for fungal growth. It is this unique pattern that led David Hughes of Harvard University to a 48 million year old leaf with similar markings. According to a Nature News article, Hughes contacted Conrad Labandeira, a palaeoecologist at the Smithsonian’s National Museum of Natural History, who, as it turned out, had noticed a leaf with strange cuts along the veins. As Hughes said in the article, “It is not normal ant behavior to bite into the leaf vein because it has no real nutritional value to the ant and can in fact be toxic in some plant species.”
The marks found as part of the fossil, as Hughes explained in a Biology Letters study published online this week, indicated that the carpenter ant was likely infected with the parasitic fungus when it bit the leaf. As reported in Discover Magazine’s blog 80beats, “If Hughes’ dating is correct, then the fungi have had plenty of time to fine-tune their zombifying practice into the ruthlessly efficient mind control we see today.”
Photo Credit: David Hughes, from Discover‘s 80beats