I did a cursory search after reading your comment (because now I'm wondering, too), and I found this, in an interview with the directors:

Kotevska had already suspected she was a compelling character when Stefanov had brought back pictures of Hatidze after a scouting expedition to the region with the intention of making a film about bees’ crucial ecological role (source), so it seems as if it was the ecological thing that was the prompt, and then they found the woman.