Do Ants Attack Ladybugs? It Depends on the Species

Ants and Ladybugs … they are commonplace in every garden. What’s their connection? Are they enemies? Not really. If you find a ladybug and an ant in the vicinity of each other, they would maintain polite distance and go along their business in the normal course of things. Ladybugs, who are absolutely fierce predators of some types of insects, do not count ants as food. And ants, who can be carnivorous, also don’t count ladybugs among their diet.

Yet, certain species of ants do attack and occasionally kill ladybugs. What gives?

Why do Ants Attack Ladybugs?

The answer is “aphids”. You know, those pesky little critters – green, red, yellow, black – that attack your trees and leaves by the millions. Aphids are common garden pests who are also known to destroy cash crops. And ladybugs are great, since they are voracious eaters of aphids – hence they are considered to be friends of the garden.

Where do ants come in? To start with, ants themselves are friends of the garden in most cases. They build nests that aerate the soil and are themselves responsible for ridding the garden of certain kinds of pests, including but not limited to certain types of aphids. But that’s not the interesting part of the story.

Honeydew

The interesting part is “honeydew”. Aphids literally excrete this sweet nectar from their backsides, copiously and continuously, after converting plant sap to protein (which they digest) and sugar (which is not required for their sustenance and therefore expelled as honeydew). And there are several species of ants, called “sugar”, “honeydew” or simply “honey” ants, who absolutely love honeydew – it is the principal part of their diet. Due to their ability to herd their honey sources (namely, aphids), they are also called “herder” ants or “dairying” ants.

Capturing the Herd

Since time immemorial (possibly as early as 50 million years back), honeydew ants have been known to “herd” aphids, pretty much along the lines of humans maintaining a stock of cows. Swap “honeydew” for milk and you will get the picture. These herder ants literally capture (herd) a colony of aphids. There are multiple techniques they employ. First, scientists have proven that the legs of herder ants excrete a solution which impacts the aphids that step in it. They become substantially slower as they continue their business of chewing leaves. Next, the ants might go one step further. They have been known to nip off the wings of the aphids so that they can’t fly away.

Nurturing the Herd

After they have captured the herd, the ants actively care for their “milkers”. Ants will carry eggs of aphids back to their nests to care for them, protect the aphids from rain, even carry a few with them when they move. Part of this symbiotic relationship is that ants protect them from predators. In return, they get honeydew. Lots and lots of it.

To get the aphids to produce honeydew, the herder ants may simply follow them around and lick their droppings, but others will roll up to aphids and tickle their stomachs with their antenna. This massaging technique seems to work – the aphids usually poop, at which point the ants happily go to work, lapping up the sweet goo.

Ants are even known to perform certain feats of animal husbandry. They do eat some of their aphids from time to time – it’s a source of protein – same as we eat beef. But they will also cull the herd at times, eating the less productive males and keeping around females who can clone themselves and produce honeydew in great quantities.

Protection from Ladybugs

As part of their desire to protect the aphid herd, honeydew ants don’t take kindly to stray ladybugs that show up among the aphids. A single ladybug can wreak absolute havoc among hundreds of thousands of aphids. If an ant is alone, it won’t do much since it may not be strong enough to overcome a ladybug. If, however, the ladybug is alone, and the ant has friends alongside, the picture changes – it is under those conditions that ants will attack and even kill ladybugs.

How Do Ants Harm Ladybugs?

As mentioned previously, ants will only attack ladybugs if (a) the latter is actively engaged in wiping out the ants’ dairy farm of aphids, and (b) if an army of ants is there in strength to attack and defend their turf. If they have the advantage of numbers, ants can go in low and cause some damage by a number of means.

First, ants have powerful mandibles that can bite into a ladybug’s skin, provided they can penetrate through the ladybug’s scaly hard outer shell (elytra). The interesting thing is that if the ant attacks from the underside of the ladybug, that area is typically unprotected. The other part is that the ladybug may not want to move from its feast unless the ants really begin to bother it – by which time it may be too late with a swarm of ants attacking. When the ladybug tries to fly away, it has to open the elytra above its wings, exposing more of the softer wings and the tender skin underneath and giving the ants more purchase. In addition to the strength of the bite, many types of honey ants produce formic acid (as in the Myrmecocystus species in the US and its cousin, the Plagiolepis species in South Africa). This is a toxin that can kill a ladybug, especially if delivered through the softer skin and tissue underneath the elytra.

If the ants do kill the ladybug, they will drag the carcass back to their nest for food.

Is This a Common Occurrence?

Honeydew ants are very common in every corner of the world. So are aphids and ladybugs. So the short answer is “yes”, ants attacking and/or killing ladybugs are a common occurrence. Chances are, its going on in your garden right now.

What Species of Ants Attack Ladybugs?

There are some common ants that feed on honeydew from aphids and other scale insects. One feature that distinguishes the species is that the honey which is gathered is fed to a “replete” (also called a plerergate or rotund) – a worker ant that is fed honey by others, till its abdomen becomes distended with it. The replete hangs from the ceiling of an underground chamber for long periods of time, sometimes months on end. In times of need, the colony summons the replete. Its abdomen is stimulated, and it disgorges the honey – which is then enjoyed by the colony of ants.

Interestingly enough, different species of honey ants apparently developed this method of storage independent of one another. There are a number of honey ant species. Some common ones are:

1. Black Carpenter Ant (Camponotus): Carpenter ants are abundant all across North America. Among the 50 or so species, the common black carpenter ant seeks aphids for honeydew. The Camponotus inflatus from Australia also feeds on honeydew.

2. Honeypot Ant (Myrmecocystus): These brownish-yellow honeypot ants are very common in the arid Western deserts of the US, where some 30 species of them are found. The most common species is Myrmecocystus mexicanus.

3. Yellow Citronella Ant / Larger Yellow Ant (Lasius interjectus): These ants emit a lemony citronella odor and are also premier honey ants. They are found along a wide band in the Northern plains of the US and down the East Coast in Florida and Mexico.

4. Argentine Ant (Linepithema humile): This invasive species, originally native to Argentina, Uruguary, Paraguay, Bolivia and Southern Brazil, has now spread globally, including the Continental US. There are several species of dairying ants among them.

5. Red Honey Ant (Melophorus bagoti): This subspecies, found in the Great Australian Outback deserts, is a well-known honey ant speces.

6. Sahara Desert Ant (Cataglyphis bicolor): Cataglyphis species are found in arid areas of North Africa. Several members of the species feed on honeydew, though others are scavengers that feed on dead insects.

7. Spider Ants (Leptomyrmex): Several species of the spider ant family, found in South American rain forests and other wet habitats, are honey ants.

8. Plagiolepis: These formic acid producing ants, the equivalent of the Myrmecocystus in the US, are found in South Africa and other parts of the Old World.

9. Prenolepis: Prenolepis is a subfamily of ants found all over the world, including North America, Asia, western Africa, southern Europe, Anatolia, Cuba and Haiti.

Each and every species mentioned above is fully prepared to protect its turf under the right circumstances. They are the ones who will attack and possibly kill ladybugs if their herd of aphids is being threatened.

What Parts of the World Does this Happen?

As the descriptions above show, honey ants are present in great number in every continent. A number of them are found in arid climates, such as the Myrmecocystus in western US, the Plagiolepis in South Africa, the Cataglyphis in North Africa and Sahara region and the Melophorus bagoti in Australia, but this is hardly a rule of thumb. Black Carpenter Ants and Argentine Ants are around in every garden almost in the US. There are other species common in tropical, subtropical and rain forest climates around the world.

Are Ants Eating Ladybugs Something to Worry about in Your Garden?

It depends. Certain types of honey ants, while they may kill a ladybug or five, are actually good citizens in your garden. They contribute by aerating the soil and taking care of other pests. However, certain honey ants, such as Argentine Ants, are a significant pest that can take over your garden. If they are also killing your ladybugs, it may be time for some action.

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