TABLE 1.
Biomarkers of leafhopper density in order of the strength of correlation to the RDA constrained axis.
| Compound | Response type | Linear Slope | Change point | ΔIntercept | Aromaa | Biosynthesis |
| cis-3-Hexenyl butyrate | Linear | 3.941 | – | – | Wine, green | FA derivativeb |
| (E,E)-α-Farnesene | Step | – | 0.312 | 7.21 | Woody, sweet, green, floral | Sesquiterpenec |
| Sulcatone | Linear | 4.11 | – | – | Citrus, green, musty, cheesy | Irregular terpenec |
| (3Z)-Hexenyl hexanoate | Step | – | 0.579 | 2.651 | Green, fruity, fatty, tropical | FA derivativeb |
| unknown 3 | Linear | 2.293 | – | – | – | – |
| (E)-β-Ocimene | Step | – | 0.25 | 7.119 | Citrus, green, terpene | Monoterpenec |
| trans-Dehydroxylinalool oxide | Step | – | 0.625 | 2.297 | Herbal, green, terpene | Monoterpened |
| cis-Linalool oxide (pyranoid) | Step | – | 0.429 | 2.456 | Citrus, green | Monoterpened |
| cis-Linalool oxide (furanoid) | Linear | 3.65 | – | – | Earthy, floral, sweet, woody | Monoterpened |
| (E,E)-Allo-ocimene | Step | – | 0.25 | 3.065 | Terpenic, sweet, fresh, floral | Monoterpenec |
| Indole | Step | – | 0.682 | 1.601 | Concentrated = fecal, animal dilute = sweet, floral | Anthranilateb |
| Diendiol I (2,6-Dimethylocta-3,7-diene-2,6-diol) | Linear | 3.673 | – | – | – | Monoterpenee |
| Benzyl alcohol | Linear | 2.276 | – | – | Fruity, floral, sweet | VPBb |
| β-Myrcene | Step | – | 0.625 | 1.101 | Balsamic, must, spice | Monoterpenec |
| trans-α-Bergamotene | Step | – | 0.429 | 2.5 | Woody, warm, tea | Sesquiterpenec |
| cis-3-Hexenyl isovalerate | Step | – | 0.579 | 1.853 | Fresh, green, apple, fruity, tropical | FA derivativec |
| Heptanoic acid | Null | – | – | – | Cheesy, sour, rancid | FAf |
| Hexanoic acid | Null | – | – | – | Cheesy, fatty | FAf |
| (Z)-β-Ocimene | Linear | 3.321 | – | – | Citrus, herbal, floral | Monoterpenec |
| (E)-2-Hexenyl acetate | Linear | 1.676 | – | – | Sweet, apple skin, banana peel | FA derivativeb |
| 1-Non-anol | Linear | 1.716 | – | – | Fatty, green, orange | FA derivativeb |
| Decanal | Null | – | – | – | Citrus, sweet, waxy | – |
| Cyclopentenone | Null | – | – | – | – | FA derivativeg |
| trans-Linalool oxide (furanoid) | Null | – | – | – | Earthy, floral, sweet, woody | Monoterpened |
| γ-Non-alactone | Step | – | 0.579 | 1.606 | Coconut, creamy, waxy, sweet | FA derivativeh |
| γ-Butyrolactone | Null | – | – | – | Caramel, fatty, sweet | FA derivativeh |
| unknown 2 | Null | – | – | – | – | – |
| p-Xylene | Linear | 2.198 | – | – | Sweet | – |
| 1-Octen-3-ol | Null | – | – | – | Mushroomy, green, earthy | FA derivativeh |
| Benzyl nitrile | Null | – | – | – | – | VPBi |
| Octanoic acid | Null | – | – | – | Cheesy, fatty, waxy | FAf |
| Butylated hydroxytoluene | Null | – | – | – | Phenolic, camphor | – |
| Linalool | Null | – | – | – | Flower, lavender | Monoterpenec |
| Cyclopentanone | Linear | -2.219 | – | – | Minty | FA derivativeg |
| Coumaran | Step | – | 0.769 | 2.088 | – | – |
For step function relationships, the change point, in units of leafhoppers per young leaf, and the difference in intercepts after and before the change point are reported. Biosynthetic pathways are reported when available from the literature (FA, fatty acid; VPB, volatile phenylpropanoid/benzenoid compounds derived from phenylalanine). aThe Good Scents Company, (2015), bDudareva et al. (2013), cKnudsen et al. (2006), dHo et al. (2015), eZeng et al. (2019), fKroumova et al. (1994), gWeber (2002), hSchwab et al. (2008), iNoge and Tamogami (2013).