At high noon, as if programmed, the ant plunges its mandibles into the juicy main vein of a leaf and soon dies.
Within days the stem of a fungus sprouts from the dead ant's head.
Ants appear to die within six hours after their final bite.
Fossil evidence implies that this zombifying infection might have been happening for at least 48 million years.
An unsuspecting worker ant in Brazil's rainforest leaves its nest one morning.
But instead of following the well-worn treetop paths of its nest mates, this ant stumbles along clumsily, walking in aimless circles, convulsing from time to time.
The zombies' bites are synchronized near noon (possibly cued by clock genes in the fungus) and usually occur in a north-northwestern orientation.
Scientists have found that the fungus also triggers atrophy in its victim's muscles—specifically those around its mandibles.