Perceived severity of various threats for beekeeping. Comparisons between respondents from the invaded and the non-invaded range of the species. Answers were provided on a unipolar scale ranging from “Not at all serious” (+1) to “Extremely serious” (+5) (y-axis). Bubbles were centered on the median score of each answer, and their size was proportional to the Potential for Conflict Index, which ranged between 0 (no disagreement, all answers on the same point of the scale) and 1 (respondents were equally divided between the two opposite points of the scale). Bubbles on the left (in green) represented answers from respondents living in non-invaded areas, while bubbles on the right (in red) represented answers from respondents living in invaded areas.