Decapitator flies place their larvae inside the ant's thorax, giving the ant only a few weeks to live before it is eaten from the inside out. (Photo by armi fauzi/500px via Getty Images)
Zombies are among us. These little undead creatures are everywhere. In this excerpt from Rise of the Zombie Beetles (Johns Hopkins University Press, 2025), author Mindy Weisberger discusses the sad plight of worker ants who are zombified by the fly Pseudacteon wasmanni.
Scientists first reported the gruesome habits of the Pseudacteon beheading ant more than ninety years ago, while studying ant populations in Europe, South America and the United States. The female fly begins by hunting a worker ant, carefully keeping her distance because she is no bigger than her victim's head.
Lloyd Morrison, an ecologist with the National Park Service, noted in his guide to insect parasitoids in North America that to researchers observing phorids in the field, “they appear as tiny, fuzzy dots hovering above their host ants.”
Females don’t have much time to be picky about their hosts, since adult flies live in the wild for only about a week or less. When a female fly finds a suitable spot, she quickly lays an egg in the ant’s thorax—and away she goes—in less than a second (analysis of the female reproductive system of the phorid fly Pseudacteon wasmanni has shown that the eggs are torpedo-shaped and 130 micrometers long, or about 0.005 inches).
A single female Pseudacteon can lay between 200 and almost 300 eggs, and she can make over 100 parasitization attempts in an hour (although only one egg is laid per host).
Newly infected worker ants “often appear confused after laying eggs,” writes U.S. Department of Agriculture entomologist Sanford Porter in the journal Florida Entomologist, and the ants “often stand still for several seconds or minutes before running away.”
These egg-laying attempts are not always successful; in fact, most fail. In laboratory experiments, when female Pseudacteon tried to implant an egg into an unwilling ant, they failed at least 65% of the time. But when the egg does get inside the ant, its host becomes a victim of its captor’s manipulation. Once the egg hatches, the ant has only a few weeks to live before it succumbs to the parasite’s control, stumbling away from its home and family, and then undergoing internal decapitation.
Sourse: www.livescience.com
