Cumulative number of individuals that produced an first anal droplet χ21= 0, p=0.981 χ21= 0.2, p= 0.691 χ21= 1.6, p= 0.205 χ21= 1.1, p= 0.302 p= 0.633 p= 0.653 χ21= 0.1, p= 0.752 χ21= 2.9, p=0.086 Second instar Focal larva: First instar Cumulative number of individuals that produced an first anal droplet Before treatment After treatment Synthetic pheromone Natural pheromone Cyclohexane Time (s) Figure SA. Timing of production of first droplet. Shown are cumulative number of first droplets before treatment (pooled for all treatments, N=75) and after treatment (release of natural pheromone, synthetic pheromone or cyclohexane, N = 25 each). Focal larvae are either first instar (upper graphs) or second instar (lower graphs). Companion larvae are either first instar (black circles) or second instar (white circles). No significant differences were found.

Second instar Focal larva: First instar Before treatment χ21= 0.2, p= 0.665 χ21= 0.6, p= 0.435 χ21= 0.3, p= 0.61 χ21= 1.2, p= 0.273 χ21= 2.1, p= 0.149 χ21= 0.1, p= 0.813 p= 0.447 p= 0.805 Second instar Focal larva: First instar Before treatment After treatment Cumulative number of individuals that displayed first swing of their abdomen Time (s) Synthetic pheromone Natural pheromone Cyclohexane Figure SB. Timing of first swing. Shown are first swings before treatment (pooled for all treatments, N=75) and after treatment (release of natural pheromone, synthetic pheromone or cyclohexane, N = 25 each). Focal larvae are either first instar (upper graphs) or second instar (lower graphs). Companion larvae are either first instar (black circles) or second instar (white circles). No significant differences were found.

Cumulative number of individuals that produced an anal droplet Droplet production Before treatment After treatment First instar First instar χ24= 4.5, p= 0.34 Cumulative number of individuals that produced an anal droplet Second instar Second instar χ24= 8.8, p= 0.07 Time (s) Figure SC. Timing of production of first droplet. Shown are the number of individuals that have excreted a droplet before treatment (pooled for all treatments, N=125) and after treatment (blend of synthetic pheromone with amount and ratio of second-instar larvae (gray circles), amount of second-instar larvae and ratio of first instar larvae (gray triangles), amount of first-instar larvae and ratio of second-instar larvae (white squares), amount and ratio of first-instar larvae (black stars) or cyclohexane as the solvent control (gray hex), N = 25 each). Focal larvae are either first instar (upper graphs) or second instar (lower graphs). No significant differences were found.

Swing Before treatment After treatment First instar First instar χ24= 1.9, p= 0.76 Cumulative number of individuals that displayed first swing of their abdomen Second instar Second instar χ24= 7.8, p= 0.10 Time (s) Figure SD. Timing of first swing. Shown are first swings before treatment (pooled for all treatments, N=125) and after treatment (blend of synthetic pheromone with amount and ratio of second-instar larvae (gray circles), amount of second-instar larvae and ratio of first instar larvae (gray triangles), amount of first-instar larvae and ratio of second-instar larvae (white squares), amount and ratio of first-instar larvae (black stars) or cyclohexane as the solvent control (gray hex), N = 25 each). Focal larvae are either first instar (upper graphs) or second instar (lower graphs). No significant differences were found.

Cumulative number of individuals that displayed first partial crossing Partial crossings Before treatment After treatment First instar χ24= 1.9, p= 0.76 Cumulative number of individuals that displayed first partial crossing Second instar χ24= 7.8, p= 0.10 Time (s) Figure SE. Timing of first partial crossing. Shown are first partial crossings before treatment (pooled for all treatments, N=125) and after treatment (blend of synthetic pheromone with amount and ratio of second-instar larvae (gray circles), amount of second-instar larvae and ratio of first instar larvae (gray triangles), amount of first-instar larvae and ratio of second-instar larvae (white squares), amount and ratio of first-instar larvae (black stars) or cyclohexane as the solvent control (gray hex), N = 25 each). Focal larvae are either first instar (upper graphs) or second instar (lower graphs). No significant differences were found.