Results of cluster analysis, showing how similar the chemoattraction response of 21 Pristionchus pacificus strains was toward: all tested compounds, organic compounds only, and beetle washes only. Nematode origin information (original beetle host association and geographic location) is given on the x-axis for each strain (Ado, Adoretus sp.; Hop, Hoplia retusa; Hch, Hoplochelus marginalis; Mal, Maladera affinis; Ory, Oryctes borbonicus; GE, Grand Etang; TB, Trois Bassin; ES, Etang Salé; TBG, Trois Bassin Garden; SB, Saint Benoit; CAL, California; USA). All strains are of genetic lineage, “C,” except the reference strain, RS2333, which is lineage “A” (Morgan et al. 2012). See Tables 1, 4 for further information.