It was Tuesday when I first realized that something was wrong. After a hard day’s work down in the forest, I was headed back up to the colony with my friend Bill. He’d been acting weird earlier, having trouble walking and not knowing where he was. I thought that he was just acting to get out of having to work, so I didn’t pay him much attention as I started to climb the tree. About halfway up, though, I realized that he wasn’t following.
“Bill? We have to go back now. Hurry up!” I called. There was no response. I tried again.
“Bill? The queen won’t be happy if we’re late!” I called again, this time a bit louder. But there was still nothing.
“Bill?” I asked. “This isn’t funny! Could you just say something so that I know you’re okay?” I strained my ears, trying to pick up his voice, but there was silence. Climbing down, I found him laying against a tree. I started yelling at him. Why hadn’t he answered me? Where was the wood he’d gathered? Why wasn’t he climbing up to the colony? His response shocked me: He felt “too weak” to climb, so he was spending the night in the forest!
Fine, I thought, as I climbed up alone. He’ll realize his mistake and be back up before the sun rises. But two days later, there was still no sign of him. Okay, now I was starting to get worried. Usually Bill would have gotten tired of this by now! With a few other ants, I launched a search party.
I was the one who spotted him. He was climbing up to a leaf. I called out to him, but he didn’t answer. Had I done something wrong? As I watched, Bill bit down onto the vein of the leaf. An older ant gasped.
“The fungus! It’s the fungus!” he cried. “We need to leave now!”
“What fungus?” I asked as we scurried away.
The ant explained that Bill had been infected by a fungus, which had been slowly eating away at his insides. Now, the fungus was controlling him, which was why he’d climbed up to the leaf when he’d claimed that he was too weak to climb. Biting the vein meant that he wouldn’t fall off. I was also told to stay away from Bill, because I could get infected by the fungus if I got too close. The other ants wouldn’t even let me say goodbye- they said that he’d be dead in hours anyway.
Over the next few days, I tried to avoid his body. Just the thought of my best friend lying there dead, stuck to a leaf, was enough to bring me to tears. But then it occurred to me that Bill hadn’t gotten a funeral like all of the other ants, so I made up my mind to give him one.
When I found him, I was shocked. There was a stem growing out of his head! He was still my best friend, though, no matter what had happened to him. After several attempts, I realized that I wasn’t going to be able to knock him down without hurting myself or requiring help. I had to admit defeat and move on.
“Goodbye, Bill” I whispered. As I turned away, a fungus spore landed on my back. I didn’t notice.
Warning! The “Zombie fungus”, or Ophiocordyceps Unilateralis, is very real! Fortunately, humans are not affected by it, but millions of Carpenter Ants have fallen victim to the fungus.
When a fungus spore lands on an ant, it attaches itself to the ant’s exoskeleton. Then it gradually increases pressure until it “explodes” into the soft belly underneath. This “explosion” causes the ant to convulse, and it falls from the tree. Next, the fungus creates a neurotoxin, which makes the ant uncoordinated and clumsy. After about two days, the neurotoxin makes the ant climb to a leaf or stick about 25cm from the ground. There, the ant is made to bite the vein of the leaf or stick. This is called “The Death Grip”. The ant will be dead within 6 hours. Once the fungus grows through the dead ant’s head, it can drop more spores onto the unsuspecting ants below. Fun fact! O. unilateralis and the Carpenter Ant have been coexisting for 48 million years.