By Chris Post
New research published in the journal Nature sheds some light into the behavior of zombie ants during the last stages of their undead existence.
David Hughes at Pennsylvania State University in University Park and his colleagues are looking into the ants, who are the victims of a fungal infection, and determined that the fungus adapts to changes in climate by changing the infected ants’ behavior.
Hughes and his associates examined the cadavers of zombie ants as well as images from collections around the world. Rather than looking at the ants themselves, researchers recorded what the ants were biting when they died. According to the findings published in Nature, zombie ants in tropical climates were more likely to bite leaves than twigs. They surmised this is because trees in those climates do not shed their leaves. This seemed to be confirmed by findings that ants in temperate climates were more likely to bite twigs, meaning insects were likely to stay put as leaves dropped.
Next, researchers looked at the DNA of the fungus (Ophiocordyceps unilateralis). It was determined that the twig biting strain had evolved independently, diverging from the leaf biting strain on several occasions.