Sunflowers are very attractive to aphids, therefore I normally have a couple of them growing amongst my flowers. And where aphid colonies exist, ants are sure to follow. Just before I took this pic, I noticed the aphids on the underside of the leaves and what amazed me was the fact that each aphid had its own ant!
Ants are attracted to aphids because of a sticky, sweet substance they produce when feeding, called honeydew. Honeydew isn’t the sole food source for ants, but when an aphid colony is in the area, the ants can harvest this nutrient-rich substance continually with less effort than what is required to constantly locate new food sources. Because of this, ants protect aphid colonies ferociously, warding off other pests and parasites. I just leave the aphids, they never seem to do much damage to the sunflowers and at least it keeps them away from my other flowers.
As I do not use any pesticides in my garden whatsoever, I normally eliminate aphids from my flowers with blasts of water from a garden hose. Once dislodged, the pests are unable to re-attach before they die.
I took two of the ants and put them on a wooden pole on my patio so I could get a picture, It was almost impossible to get a picture of them at the bottom of the leaves. These two just sat there, unsure of what was happening and why they were in a strange place. After I took the photograph, I edged them back onto the sheet of paper and placed them back on the leaf, where they immediately started running around trying to get their bearings.
The sunflower (Helianthus annuus) is an annual plant native to the Americas.