Do Ants Eat Cactus? [A Fascinating Relationship]

You look out one morning at your cactus to find a swarm of ants on your plant and wonder to yourself if they will pose a danger to it. While you think that ants will dislike the cactus like most animals, now you wonder if you may need to protect your cactus. Do ants eat cacti?

Ants do love the cactus because they secrete a sugary nectar at the spine, but they don’t eat the cactus itself—they have more of a symbiotic relationship. The cactus secretes this nectar to attract the ants and control the aphids, mealybugs and scales that can kill a cactus. 

If you’d like to learn more about ants and their fascinating relationship with this plant, keep reading as we explore it further in depth. 

Ants and Cactus: Relationship of Mutual Benefit

What is a symbiotic relationship? It means that both in the relationship benefit. The cactus benefits from the ants killing the aphids, mealybugs and scales that could kill it. At the same time, the ants benefit from this sugary nectar secreted from the cactus to attract the ants.

Anything that will threaten the ants and their access to this nectar fountain will receive a proper lashing from the ants. Without the ants, the cactus may prove vulnerable because it can’t defend itself, so it uses the ants as a barrier of protection. 

As a side note, plant experts say that ants also improve the soil as well, which will help the cactus in its growth. They also kill pests in the soil. 

Can Ants Kill a Cactus?

Ants pose little danger to the cactus compared to other pests like mealybugs, scales and aphids. This is one of the reasons that the cactus will produce a nectar to bring in the ants to kill some of the other pests more dangerous to it. 

When ants depend on a food source for their colony, they will grow aggressive in defending it, especially some species of ants. Ants are after one thing when it comes to the cactus—sugar. Not only will they take it from the nectar of the cactus, but they can target the scale and mealybugs, which produce sugar. Don’t let them do this, however. 

What Cactus Do Ants Love?

Let’s take a look at some of the cactus that ants will go after because of the sweet nectar that they produce:

  • Ferocactus (infamous for doing this)
  • Opuntia
  • Coryphantha 
  • Thelocactus
  • Echinocactus
  • Sclerocactus
  • Cylindropuntia

Think of the cacti that have extrafloral nectaries in their patches, and these cacti tend to attract the ants. 

Expert Tip: Your cactus will even lose water in an effort to attract the ants. For that reason, you may want to give it a bit of extra water to keep it safe from drying out. 

How to Get Rid of Ants on a Cactus

While they don’t usually pose a direct danger, they can introduce mealybugs or aphids to the cactus, which can indirectly cause problems. If you happen to see a few ants around the cactus, it won’t cause much for problems. Many times, this will indicate that they went there because of pests on the cactus, which can pose an actual threat to the cactus. 

Should an ant infestation start to seem out of control, it would be best if you were to remove the cactus from the potting soil. Be aware of where they receive their food source as well and remove what attracted them to begin with since it won’t do any good otherwise. 

Related Article: Can Rabbits Eat Christmas Cactus?

Are Ants Bad for Cactus?

I would give a definite no on this that ants don’t pose a threat to your cactus. In fact, they’re mostly beneficial unless in huge numbers. Ants will clean away the microbes like fungi and bacteria that can harm your cactus, and they will keep the pests away. Ants will attack other insect larvae in the soil that might threaten your cactus. 

For that reason, I wouldn’t recommend using ant insecticide for your cactus since it will do more harm than good. In many cases, the cactus purposely attracts the ants to it as a way to eliminate other pests that would kill it off. 

Ant-Cactus Mutualism in the Sonora Desert

Let’s take another excellent example of ants and their relationship with cactus in the desert. Most cactus experts believe that the cacti benefit as much as the ants from an ant nest nearby. Many of the ants in the Sonora Desert are believed to have even evolved with the cactus. Especially during a drought in the Sonora Desert, they would take up refuge in the cactus and defend it as a food source aggressively. 

Whenever ants sense they may have hurt their food source, they will peel out of the cactus quickly to prevent damage to this food source. In other words, they have an interest in keeping the cactus healthy. 

Some studies showed how the ants would use the cactus as a source of carbohydrates, and they would even become aggressive against other colonies fighting for the same cactus. 

You even have an ant named for a cactus that it commonly defends called the crematogaster opuntiae. This ant often takes up residence in the opuntia plants out in the Sonora and the Chihuahuan deserts. 

Backfired: When Ants Prove Harmful

Ants are often a sign of other pests in the plants that could kill your cactus since the cactus lure them there with sweet nectar. You do have one time when ants can prove harmful to your cactus. Never let ants farm the mealybugs, aphids or scales for their sugar. This may sound hilarious—it does to me—yes, ants will sometimes domesticate and protect the mealybugs, aphids and scales for their sugar. 

The issue with it is that they don’t kill the harmful pests in your cactus, and if you have a collection of cactus with ants and mealybugs, it becomes the perfect storm as ants will move them around and milk them for their sugar. This can hasten the death of your entire cactus collection, which explains why some gardeners choose to kill ants on sight. 

However, it can serve as a barrier of protection when the ants defend the plant itself from pests, but you must keep a close eye on it. 

Final Thoughts

In general, you don’t need to worry too much about ants eating your cactus because it serves as more of an indirect food source to them. They don’t want to destroy that by killing your cactus. They will even protect it. The only time where you need to worry in a big way is if you see tons and tons of ants surrounding your cactus because it may cause problems for your plant in some of those cases. 

Also, beware of when the ants start to protect the pests for their sugar since this can also end badly. 

Ants and cactus even evolved together over time, and this symbiotic relationship has continued to this day. You may even begin to think that your cactus attracts the ants, and you may not be far off the mark with that thought. 

Did this all sound fascinating how cactus will attract ants purposely to handle their pests? It certainly did to me, but I had learned of this practice and the incredible intelligence of plants in the book, The Hidden Life of Trees. I would especially recommend this book for anyone who wants to feel wonder at the wondrous mysteries and beauties of nature. 

Leave a Comment