Super Fly: The Unexpected Lives of the World's Most Successful Insects

by Jonathan Balcombe

You might guess that such an abundant and diverse food reservoir as flies would also play host to their own parasites. Among the most manipulative of these is a Cordyceps fungus whose spores, upon infiltrating a housefly, sprout tendrils that suck up nutrients, causing the fly’s abdomen to swell. When the fungus is sufficiently mature, it turns the fly into a fungus-serving robot. The fly gets an irresistible urge to go to a high place, such as a shrub or a building eave. Arriving at its perch, the fly sticks out its feeding proboscis and uses it as a clamp, gluing itself to the perch. There affixed, the fly buzzes its wings a few minutes, then locks them upright while its abdomen is aimed skyward. The fly dies in this position as the tips of the fungal tendrils push their way out of the insect’s body. The fly corpse has become an ideal rocket launcher for the spores, which catapult upward from the tendril tips, creating an airborne mist whose spores are more likely to land on other, unsuspecting flies, to start the life cycle again. Even the timing of the spore ejection is under the fungus’s control. Spore release is delayed until sunset, when cool, dewy air provides the best chance for spores to develop quickly on their fly hosts.