In predation, that is the relationship in which members of one species consume members of another, predator population tends to increase along with prey population. For example, the more rabbits there are in an area, the more foxes there will be to prey on them.
Ants and aphids share a similar relationship. When aphids infest plants, you can expect ants to follow. The difference however, is that their relationship isn’t typically based on predation. While some ant species may eat aphids, most of them form mutualistic relationships with them instead.
In this article we’ll look deeper into this mutualistic relationship and a specific case wherein ants turn their back on such a relationship and end up eating aphids instead.
But first, a little background on aphids.
What Are Aphids?
Whether you’re into farming and gardening or not, you’ve probably heard or came across one of these plant-sucking insects at least once in your entire life. That’s because they are pretty prolific tiny insects and are often found clumping about on the underside of leaves, forming large colonies in a matter of days.
They have soft, pear-shaped bodies with long legs, but are best known for their piercing-sucking mouthparts, long, slender, tubular, and straw-like in appearance. They may appear wooly or waxy and come in various colors, the most common of which are green, red, and white.
Aphids On Plants
Among all known insect pests in agriculture, aphids are one of the most annoying of the bunch. When they see aphids sticking on their crops, farmers already know that their precious plants are in for many problems.
It’s not just because aphids are sap and nutrient-sucking vampires of plants, but also due to the number of secondary pests and diseases they bring about on the field or in the garden. Often considered as the harbinger of plagues, aphids are known to be important plant virus vectors capable of transmitting diseases.
Meanwhile, aphid saliva often causes growth distortions on some plant portions and flower malformation when injected upon feeding. Not only that, their “poop” even attracts fungi growth in the form of sooty mold that produces a black cape on the plant’s surface.
But what makes aphids bothersome is their uncanny ability to attract colonies of ants. When ants get a whiff of aphids, they would relocate, create a mound and burrow on the base of the plant where the aphids are to join them on the fiesta. And, of course, this whole situation opens up another set of problems for farmers.
Ants and aphids create what scientists call a mutualistic relationship. Simply put, it’s a kind of relationship status where both parties benefit from each other and are capable of cohabiting together harmoniously despite their differences, working together for their survival. But what do these two get from each other, you ask?
Remember that “poop” that aphids produce, which attracts sooty mold? Well, it’s the very same substance that makes ants go crazy. Aphids produce honeydew, a sweet sugary excretion produced after feeding on the sap of plants. Take note that it’s sweet, and you already know what happens to ants when they get a whiff of sweet things. They invade and devour.
In exchange for the honeydew, ants, in turn, become the aphids’ army of bodyguards and caretakers. Ants, being the ferocious horde, are effective protectors against predators who wish to take a bite from a juicy aphid. Or even from humans trying to remove the aphids from their crops. They would also go all out to make sure that aphids are well-fed and taken care of to make sure that they keep producing honeydew.
Do Ants Enslave Aphids?
Researchers have often joked that ants are cattle farmers and the aphids their cow herds. The reference may seem funny, but it does describe the relationship in a way.
The milk, which in this case is the honeydew, is a valuable food source for ants. And they would do everything to ensure that food production is continuous, which means feeding and protecting the aphids.
Studies have shown that aphids thrive best when they are together with ants as compared to those who try to survive on their own. What’s more, researchers have even discovered that some ant species would even go as far as bringing the best aphids into their burrow and raising them just like livestock, forcing them to produce honeydew all year long.
What’s worse is if ants notice that some aphids are not performing well, they eat them up to ensure that production is of top quality. It’s crazy, I know. But that’s just how these two organisms roll in order to survive.
Acacia Trees Over Aphids
Ants have shown to prefer a relationship with African acacia trees over aphids. Instead of the aforementioned mutualism between the two insects, predation occurs as ants attack and eat aphids in exchange for shelter and nutrients (nectar) provided by the tree. Perhaps honeydew isn’t as sweet.
So, to sum things up, ants and aphids are usually best buddies that rely on each other to keep on living. One gives food while the other protects. But in extreme cases, the food producer becomes food itself if the guard deems it. Of course, that’s only for certain ant species or based on the presence of a third-party.