We found this tiny 22-spot ladybird on a dead hogweed stem in Teesdale a couple of days ago. Teesdale is close to the northern limit of its recorded distribution in England.
According to the UK Ladybird Survey web site this species has a particular liking for hogweed and feeds on mildews. A research paper published in 2011, which you can read here, revealed that these mildew-eating ladybirds are attracted to volatile compounds that are produced by mildew.
What's less certain is why this ant seemed to be engrossed in the hogweed stem. Maybe it too was feeding on the mildew too, or perhaps it had chewed that long trench in the stem tissue ...........
It looks like it's chewing all the soft, rotting tissue from the outer stem of the hogweed.
Whatever the reason, it was very reluctant to move and when I finally disturbed it the ant just crawled into the hogweed umbel and them resumed chewing the plant surface.