There is a species of ant that could be considered one of the most grotesque in existence because of its unusual choice of home decor – the decapitation of the heads of its victims.
Scientific studies have repeatedly found that Formica Erboldi ants tend to keep many old body parts around their dwellings. “Many ants are very clean, they remove dead workers or food debris,” said Adrian Smith, director of the Evolutionary Biology and Behavioral Research Laboratory at the North Carolina Museum of Natural Sciences.
Many ants carry their waste outside the nest and place it in a pile called Midden, which also serves as a graveyard. The main idea for a clean nest is to protect the queen from infection.
However, the Formica ants “for whatever reason, leave a large amount of their waste in their nest,” says Smith, who has been studying these insects for two years and will produce a study on his findings in 2019.
“If you break open their nests and find a lot of body parts, it’s probably because they haven’t thrown away their trash.
These skull collecting ants, which are native to Florida, are particularly fond of eating Trap-jawed Ants (Odontomachus brunneus) – typically not an easy target. The trap jaws have a strong sting and a feathered bite, hence their English name.
Unlike other ants, Formica ants do not have a sting. Instead, they spray a dose of formic acid on their victims, a charge that can put a trap ant completely out of action. “One spray can incapacitate one ant, and a single Formica ant could incapacitate an entire ant, which is remarkable considering that ants in traps are usually known as wild predators,” says Smith.
Most of the Formica ant’s food consists of trap-door ants. “I suspect they would hunt down two or three workers a day,” Smith says. And the skulls are not easily digested or decomposed: “They are the harder part of the exoskeleton, they are all hollowed out, all the muscles are gone, it’s just the skull boxes, or skulls,” he said. “They’re like discarded chicken bones.”
Another theory is that Formica keeps the remains around to chemically mimic the trap-jaw ant they feed on. “When they touch each other with their antennae, they actually smell,” Smith says. “One way to get the chemical, if they don’t make it themselves, might be to keep the carcasses they acquire to keep the smell of those ants.
Although scientists discovered these little creatures almost a century ago, stories about them have only recently become widespread.
“There are rich details all around us that we overlook or ignore,” says Smith. “These guys have always been in Florida, but they are unique. We’ve known about these ants and their strange accumulations of body parts since the 1930s, but no one has taken the time to study them. These studies give us a reason to appreciate these things, to show what’s out there, and to admire and protect them”.