I was looking at some daisies that we planted in order to help encourage hover flies and bees into the garden the other day and noticed that there were a lot of greenfly all over the plant and particularly up around the flower buds. I went over to inspect it's neighbour to see how many greenfly were on that one and there wasn't a single one to be found. For a few days I though this was just a strange coincidence until I spotted an ant half way up one of the stalks of the infested plant. "Green fly farming!" I thought.
So I spent a while watching them the other day trying to figure out exactly what they were doing with the greenfly. I didn't see any flies being moved around but apparently the ants do place the greenfly on the plants, spreading them out nicely. The two ants above seemed to be sucking up a sap like substance that I could see on the leaves. This turns out to be a sweet nectar that the greenfly excrete. The ants take this back to the nest to feed the queen and whoever else can't feed themselves.
"Ant sky scraper farm"
Tending the livestock.
The plant right beside is completely free from greenfly.
Yesterday I saw a ladybird on top of the plant having a look around. The friendly appearance on the plant made me think twice before ripping it or trying to wipe out the farm. As we are constantly being warned about the declining numbers of insects and wildlife I am unsure of what to do with this farm. Greenfly are a major food source for lady bird and hover fly larvae and at least one ladybird has already found this plant and may have already laid eggs here. There is a whole little food chain in operation on this plant which may have more positive effects than negative. The greenfly may be a nuisance to us and our vegetables but they are a resource to the ants, lady birds and hover fly. These insects are eaten by other insects and animals. How many animals are benefiting from this farm? I haven't a clue! But at the moment it isn't bothering me too much so I'll leave it for a while.
I'll keep on eye on proceedings and see how things develop. If I think the problem is spreading I will have to think again about leaving the farm alone.
For more info on greenfly and their effects in the garden read this article...Greenfly