An Uneasy Relationship

The ragwort also had a dozen or so Soldier Beetles on it and their behavior was very interesting. The beetles kept approaching the caterpillars which became very agitated, waving their heads around, the beetle would then back off.

To me, this raises a couple of questions:

 

Why would soldier beetles be interested? I believe they prey on much smaller creatures like aphids.

 

Is a caterpillar really capable of recognising and reacting to a threat?

Done