Weird Wednesdays: Plants enslaving ants



The Central American acacia plant Acacia hindsii enjoys a special relationship with its neighbors. These plants are myrmecophyte—plants that rely on the help of ants to clean them, guard them from predators and generally help it survive in the wild. The members of the species Pseudomyrmex are stringent in their duties and in exchange receive housing in the plant’s thorns and copious amounts of its sweet nectar. A ant will be born, live and die on the plant in this way, never leaving it or its colony.   

It’s a pretty cushy deal for the acacia, and their insect guardians, especially because the ants are the plant’s prisoners.  

Turns out acacia isn’t as beneficial as all those clickbait ads and daytime talk shows tell you—at least, not if you’re an ant. While the symbiotic relationship between the plant and the ant proves to be mutually beneficial, the plant gets the most mileage out of it.  

Moreover, it’s a one-way street that only stays sweet as long as the ant keeps up its part of the deal. Backing out is like bowing out of a deal with the Mafia: Deadly. 

How can a plant rooted into the ground control a mobile species? Simple: Drug addiction. 

The acacia force the ants to become dependent on their nectar by deactivating a critical enzyme in the ants’ bodies: Invertase. The enzyme is used to digest sucrose, which means that as soon as the ants drink the Kool-Aid (typically as soon as they emerge from their pupa and begin consuming grown-ant food), they’re stuck on it forever, depending on the plant-produced invertase contained in the nectar to digest their acacia-catered meals. Lest the colony start to wander, the nectar from other plants proves indigestible, sending the insects back to their dealer for more.

How exactly the plant blocks the enzyme is unknown—only that it’s conducted by another plant-derived enzyme chitinase. Enzyme inhibitors are used by plants usually as a ways of defense mechanism; some plants excrete a proteinase enzyme inhibitors that interfere with nutrient absorption in herbivorous insects. Straight-up causing a chemical dependence on the insects that you’re supposed to be in a symbiotic relationship with, however, is a new level of dickery.  

Now, I’ve talked about symbiotic relationships () before. For those who need a refresher, a symbiotic relationship is when two or more organisms of different species perform tasks or behaviors for each other that mutually benefits all parties involved. An oxpecker and a rhino reap the benefits of the bird pecking ticks off of the beast’s back; the oxpecker gets a free lunch and a relatively safe place to perch, while the rhino is rid of skin parasites.  

Ants are no strangers to symbiotic relationships. Some species will raise aphids for their secretions like tiny little cows, with the aphids enjoying protection provided by their herders. The acacia-ant relationship may seem similar to this one: The ants protect and clean the plant while the plant provides housing and food. However, it’s a new precedent that one partner in the situation straight-up enforces a dependency through internal methods. These ants aren’t partners. Hell, they’re prisoners. 

However, it’s not like they’re going anywhere soon. Like a kid that takes three extra semesters to graduate to avoid paying their student loans, these ants have nowhere to go without their jailers—and the ultimate price to pay if they leave. It’s not like the acacia will let them go in any case. 

Stay away from drugs, kids. Stay weird, and stay tuned for next week for my final column: Covering news with a critical, single eye.  

Marlese Lessing is the news editor for The Daily Campus. She can be reached via email at She tweets @marlese_lessing.

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