If it`s thoughts of zombies that keep you awake at night, you shouldn`t be worried about zombie humans; it`s the carpenter ants (Camponotus castaneus) that should concern you most. When infected by a specialised fungus (Ophiocordyceps unilateralis sensu lato), the hapless ants are unable to resist its potent power. Losing free will, the unfortunate victims locate tall pieces of vegetation, marching to a high point before the fungal infection forces them to clamp their mandibles-jaws-tightly onto a leaf vein or twig. There, the ill-fated host expires, only to be consumed from within by its evil fungal lodger, ready to scatter its spores below in the hope of infecting the next unsuspecting victim. Yet, despite the insects` loss of control, Colleen Mangold from Pennsylvania State University, USA, explains that the fungus does not attack their brains directly: `the mandibular muscles ... of infected ants are extensively colonised by the fungus`, she says. Wondering how the fungus exerts control over the ants` powerful jaw muscles, Mangold and PI David Hughes decided to take a closer look inside the muscle itself. They have discovered that the fungus invades the mandibular muscles, breaks open the membrane covering the muscle fibres and forces the muscle to contract so forcefully that it wrecks the minute muscle filaments that slide past each other. The team publishes the discovery in Journal of Experimental Biology at http://jeb.biologists.org.
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