Humans are keeping and rearing cows and goats for milk since centauries. Will you believe if I say, that in the same manner ants are protecting and tending some insects in order to get special type of nutritious sugary fluid for themselves? Astonishingly, some ant species have specialised to rear insects, similarly to us humans who rear cows & goats. When you see the tiny yet strong workers closely, you will find that they are carefully protecting, grooming and monitoring a colony of insects, for this purpose they are bringing back the lost and straying insects from here and there and also protecting them from other harmful insects too. They are also carefully guarding egg masses on the tender leaves or shoots of the trees. The fluid released by these insects is a ready food source for these ants. Thus these insects group act like miniature cows and goats for these super smart ants.
In the coming monsoon months, you can easily witness such phenomena around the road side vegetation. A very interesting mutualism has evolved between ants, some insects (like Lycaenid butterfly caterpillar, plant hoppers, scale insects, aphids etc), and usually on Prosopis or Acacia trees. These insects have nectar organs that the ants drink from, and the ants allow them to eat the host tree’s leaves or suck their plant sap. The ants provide protection for the both plant and insects.
A guarding ant with catterpillar of a Lycanidae butterfly
These insects are eating or sucking the juices from the plants which, have plenty of food stored as sugar but no other nutrients such as protein. But then these insects also need more proteins, so they consume more plant juices and excrete the extra sugars in form of nectar drops. Interestingly, these honeydew droplets are very precisely given to the ants, when they smoothly stroke or tend the insect with their antenna. Insects keep holding the honeydew droplet till it is sucked by the ant. Ants use this sugar excreta as food, but for nitrogen, the ants ingest the predator insects which come attacking the nectar insects, hence meeting a dual purpose.
Guarding ants and plant hoppers egg mass
Overall, both have mutual benefits. So now ants got benefit of honeydew droplets and the insect get protection from ants but how does the third partner benefits from these two? The plant hoppers and caterpillars damage the leaves, sucking plant sap but it is not a big damage to the plant.
Juveniles of plant hoppers and protective ants
They may lose few leaves but the damage that an herbivore can do is far greater. These ants are also keeping such herbivores on bay. So the whole symbiotic relationship of insect, ant and plant benefits to each other. So the next time you see a row of ants busy marching around some tree or insect you should know that it is not without purpose. These hard working ants are eventfully occupied in their own world, and you can enjoy seeing their activity!
Adult plant hoppers and ants are miliking
Scale insects protected by ants
Tending by ants