Site Description and Host Plant Selection
I conducted field predation trials at two sites in Ann Arbor, MI, approximately 4km apart (Bird Hills Nature Area, “Bird Hills”: 42°18’09.1”N 83°45’37.9”W; Nichols Arboretum, “Arboretum”: 42°16’48.9”N 83°43’20.5”W; see supplemental figure 1). Both sites were composed of mixed coniferous-deciduous forest, and contained host plants of P. troilus caterpillars such as sassafras (Sassafras albidum ) and tulip tree (Liriodendron tulipifera ). I selected individual plants haphazardly across subsites, with at least 5m between each plant. All plants were checked for P. troilus larvae before the start of each trial and previously occupied plants (n = 17; see supplemental figure 1) were not used. Potential predators of P. troilus were present at the sites throughout the experiment (see supplemental table 2), as well as live P. troilus larvae and adults. I ran two predation trials at these sites: Trial 1 (July 3rd to July 12th) and Trial 2 (July 20th to July 30th).