Study site
The study was conducted in the experimental ponds of the University of British Columbia, Vancouver, Canada (49°14’56” N, 123°14’02” W). The site has a total of 20 artificial ponds, each of dimensions 15×25 m², arrayed across an area of 130×100 m². The two dominant species we studied, Anax junius and Rhionaeschna multicolor, are among the largest and highly mobile dragonflies in North America (Paulson, 2009).