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June 3, 2020

Ants in Your Plants!

By Amanda Rose Newton

One of the most common questions we hear is why ants start appearing on plants in the garden and how to get rid of them. To help address both those points, let’s discuss a little bit about the biology and good deeds performed by ants before diving in.

I Bet You Didn’t Know…

  • There are 12,000 identified species of ants. There are probably many more in dense, tropical regions of the planet.
  • Ants exist on every continent (aside from the obvious- they don’t make winter hats and gloves that size yet!)
  • Ants are in the same order, Hymenoptera, as Bees, Wasps, and Hornets. They are genetically closer to wasps than Bees.
  • Ants can lift 20x their body weight. This might not seem that helpful to you, but stayed tuned. This amazing feat comes in handy in the garden!
  • The most common pest species in Florida are Pavement Ants, Fire Ants, Sugar Ants, and Carpenter Ants. Many of these are also beneficial. 

Taking Care of Business…literally! 

One of the best qualities of our Ant companions is their desire to keep things tidy. Lucky for us, this extends to our own backyards and gardens!

Ants are natural decomposing machines and will happily take your lawn clippings, pet waste, food waste, etc. and help with the breakdown process.

Carpenter ants, who have a bad reputation for eating decaying wood in the home, are equally as great at consuming the same outdoors. 

Soil Cycling

Earthworms are probably the first organism that comes to mind when soil turning is discussed, but believe it or not, ants actually play just as much of a role (if not more) in improving the quality of our dirt.

Just think about the natural behavioral tendency for ants to tunnel, and it should start making sense. Tons of tiny ants in the soil = tons of soil being turned, every day.

Not to mention, ants also tend to nest underground, leaving food and other collected materials deep down in the soil to decompose into quality nutrients. This helps cycle important gases like oxygen, nitrogen, and phosphorous, all of which make our plants very happy.

In addition, nesting ants also allows for: 

  • Increased water circulation
  • Improved access of nitrogen-fixing bacteria and fungi to their needed nutrients
  • Accessible nutrients for lower food web animals at the soil level

Assistant Gardeners

There is a whole category of ants known as “seed-harvesting” because they do just that. If you want a very scientific sounding word for this practice to sound smart at cocktail parties, it is known as, “myrecochory”.

They have a mutualistic relationship with several plant species where they take on the challenge plants face – given their immobile nature – and carry their seeds to far and distant places. The first stop is usually their underground nest, and we have already discussed how nutrient-rich these spots can be, given the food storage potential. This leads to increased germination rates and once again, happy plants. Many interesting species we plant people tend to love, such as lilies, rely on ants for future success.

Ant: Destroyer of Pests

Ants like to fight! Heavily territorial, ants will defend their turf from other varieties of ants. Pavement ants, for instance, will readily battle with fire ants for space in your yard. They also prey upon the eggs of many garden and house pests such as silverfish, flies, and fleas.

One recent study even documented cases of ants preying on cockroach and bed bug eggs if they were given the opportunity. If you do not have termites currently, ants may be helping you with that. They often will patrol the barriers of your yard and keep the “undesirables” such as termites and other pests out. 

Do Ants EAT plants?

It’s natural to assume any bug on your plant is there to consume it. For ants, this is not the case at all.

Ants fall into two distinct groups: the sugar feeders and the protein/fat feeders. None of which include leafy greens!

In fact, even the notorious leafcutter ant is merely collecting leaves to feed a fungus which in turn feeds the ants. This also explains why ants love to crash your summer picnics! Sodas, meaty sandwiches, and potato chips are a dream meal for an ant. 

So, why are ants on your plants?

If you have an infestation of aphids, scale, or whiteflies, chances are this is the reason you are seeing an increase in ants. Since these sap-feeding pests are essentially drinking juice all day, their excrement is essentially pure sugar. Aptly referred to as “honeydew”, the waste of these bad bugs is like a candy invitation to ants. Ants appreciate these secretions so much that they will even guard aphids against ladybugs and tend to them like farmers. 

Ants Are a Pain

Even with all the positive attributes ants have to offer, at the end of the day, fire ants still sting and pavement ants still bite.

Having them take up residence in your garden might not be ideal, especially if you have small children or curious pets. There are a few safe remedies you can try to hopefully alleviate the problem. 

  • Get rid of honeydew producers! No free sugar treats for the ants means they will look elsewhere for food
  • Pour boiling water on anthills. Remember that fire ants are polygyne or have more than one queen. In order to kill the entire colony, you must kill the queens. 
  • Use a Spinosad-based bait, such as Fertilome Come and Get It for fire ant control
  • Try making your own DIY bait trap using borax and something sweet like honey. Just be sure to keep it out of the way of pets and children. 

Ant Appreciation

Hopefully, this gave you some thought on how ants are helpful on a day to day basis in your garden. As gardeners, we are always striving to enhance the biodiversity of our yards and communities and ants have quite a role in that. By allowing ants to take up residence in your garden, you are enabling more nutrients, food sources, and enhancing the number of species present in your community. Even if you are not quite ready to get out that “welcome” mat, when looked at from this perspective, it makes their less than desirable attributes a little easier to put up with. 

References:

Sanders, D., Frank Van Veen, F.J. Ecosystem engineering and predation: the multi-trophic impact of two ant species. Journal of Animal Ecology, 2011: 10: 1365-2656.

Lengyel, S., Gove, A.D., Latimer, A.M., Majer, J.D. Dunn, R.R. 2010 Convergent evolution of seed dispersal by ants, and phylogeny and biogeography in flowering plants: a global survey. Perspectives in Plant Ecology, Evolution, and Systematics. 12: 43-55.