Farmer ants
Farmer ants
Argentine red ants (Linepithema humile) aka Farmer ants 'milk' green aphids (Myzus persicae) by gently tapping the aphids' abdomens with their antennae; the aphids then promptly produce a droplet of honeydew for the ants to ingest.
Aphids feed primarily on the sap from plants, essentially sucking the nutrients from leaves and stems to secrete a sugary liquid called honeydew. This honeydew secretion is very sugar-rich and is devoured by farmer ants as a high-energy food source.
As a result, a mutualistic system (the National Geographic link below says the ants have gamed the system to favour them) has evolved wherein the farmer ants shepherd the aphids around to the juiciest and safest parts of plants like the undersides of leaves and protect them from predators (including lacewings, ladybugs and ladybird larvae, and hoverfly. This leaves only birds and parasitic wasps as a potential threat).
Furthermore, these ants carry the aphids back into their nests at night and for winter. Argentine red ants actively seek out these species and will even transport them to fresh parts of a plant if needed—tiny farmers, basically
In return for the protection, the ants are allowed to ‘milk’ the aphids by stroking the aphids with their antennae, coaxing them to secrete their honeydew, which is then devoured by the ant.
In every ant colony, workers specialize in different roles such as nursing or foraging. in farming ants, some workers will specialize just in shepherding and caring for the aphids!
Bane of gardeners
For gardeners, this is a big problem
Farmer ants help aphid populations explode, damaging crops and garden plants.
These aggressive ants outcompete native ants who might otherwise control aphids naturally.
The remedy is ant bait, which contains active toxicants or insecticides mixed with carbohydrates (e.g., sugars), proteins, oils, or a combination of these three that attract worker ants, which recruit other workers to it. Workers carry small portions of the slow-acting bait back to the nest, where it is transferred mouth-to-mouth to other workers, larvae, and queens to kill the entire colony. Some examples of active ingredients include boric acid (borate or various forms of sodium borate), hydramethylnon, fipronil, and avermectin B (abamectin).
Argentinian ants in California
In California, these Argentinian ants basically function as one massive supercolony from San Diego to San Francisco—the reason is that they all came from one and the same stock, possibly an import of agricultural produce sometime in 1850. Since they all have the same pheromone, there is no infighting between nests, which helps them expand fast.
Sources:
https://ipm.ucanr.edu/PMG/PESTNOTES/pn7411.html
https://www.mcgill.ca/oss/article/did-you-know/farmer-ants-and-their-aphid-herds
Comments
Also, spraying of chemical insecticides is something that we completely avoid in our SPK method ( SPK = Subhash Palekar Krishi ).
Even though SPK promotes natural substance made insecticides, we don't even do that. Since we are no longer a farm, we are a forest farm, wherein Natural checks and balances seem to have reached.
In this case it was a beautiful watercolor of an ant i saw on my social media feed
Then I let my imagination take over. Over 15 years ago I read about the super colony of red ants from Argentina that have overrun the west coast of America. That fascinated me.
My gardening experience showed me how ants farm aphids and a year ago I had blogged about it at https://talkofotherthings.blogspot.com/2024/04/the-intriguing-world-of-farmer-ants-and.html
That’s how this artwork came to be