Is it just me or does anybody else find ants and aphids together? I am sure the ants are not eating the aphids, they seem to be fussing over them, ‘farming’ them as you would do if you kept livestock. 
It may be a sugary excretion they like or something more sinister, but it seems everywhere I have aphids, green or black, I have ants. I got really close this morning and watched an ant stroking the aphid gently as if to reassure it. It was most odd!
Or perhaps I am just making too much of it and they are deciding which one to eat!
Just found this article which seems to confirm the farming theory.
- Ants and Aphids – Who Knew? (littleworldofhope.com)
Davids Garden Diary 
Hi David – have just discovered your blog, am really enjoying it, and am madly trying to catch up (with this year’s posts at least!)
I was particularly interested in this post about the ants & aphids, as I witnessed this for the first time this year on a buddleia of mine, and was really puzzled by what was going on! But now, mystery solved – brilliant 🙂
Welcome to the blog, glad you like it.
David