Ants tending a herd of aphids

 For the second year in succession we have ants nesting in one of the garden waste recycling bins, which happens to be close to a cardoon plant that's hosting numerous small colonies of black bean aphids. These attract the ants because they secrete sweet, energy rich honeydew, the waste product of the sap they siphon from the cardoon. 

The ants caress the aphids with their antennae, which stimulates the aphids to produce droplets of honeydew that the ants drink and carry back to the nest in their distended abdominal segments.

In the image above and in the final image below you can see a feeding ant's swollen abdomen, rendered almost transparent where the pigmented plates of the abdominal segments have been stretched apart.