Figure 1. Chemical analysis of nocturnal headspaces collected from plants in the habitat of M. sexta in Southern Arizona.

(A) Representative photographs (left) and chromatographs (right) of each headspace collection. x-axis of chromatographs, retention time; y-axis, abundance, same scale for all headspaces, maximum abundance indicated in Datura flower headspace; gray bar, internal standard (5 ng 1-bromodecane). (B) Number of GC-peaks. Squares, average values of 3–5 individual plant samples; whiskers, range; dotted line and gray area, average and range of control values obtained from nocturnal collections in the same habitat with empty bags (n = 2), and with unused filter material (n = 1); open squares, within control range; filled squares, outside control range. (C) Non-metric multidimensional scaling plot (Bray–Curtis, 2D stress: 0.09) based on a nontargeted analysis (https://xcmsonline.scripps.edu; Tautenhahn et al., 2012) of 69 chromatograms (Figure 1—source data 1). Color code of plant samples as in (B).