## 3 Materials and Methods  
Grass samples were collected in the summer of 2020 and shipped to KTH Royal Institute of Technology, Stockholm, Sweden. _C. exaltatus_ was collected from Rusinga Island (0\({}^{\circ}\)23\({}^{\prime}\)47.3\({}^{\prime\prime}\) S 34\({}^{\circ}\)12\({}^{\prime}\)13.1\({}^{\prime\prime}\) E) while _C. dactylon_ and _P. repens_ were collected in Mbita (0\({}^{\circ}\)26\({}^{\prime}\)06.19\({}^{\prime\prime}\) S 34\({}^{\circ}\)12\({}^{\prime}\)53.13\({}^{\prime\prime}\) E). The plants were divided into roots and shoots prior to import due to permits from the Swedish Board of Agriculture. Roots include any plant tissue that is present below the ground, while shoots refer to any part of the plant tissue that is above the ground. Botanical identification was performed at the International Centre of Insect Physiology and Ecology Thomas Odhiambo Mbita Campus (ICIPE) in Kenya. Upon arrival, both parts (shoots and roots) of the grass were washed in order to remove any residual soil left on the plant material. The plant material was washed using doubly distilled water (Milli-Q) from a Synergy 185 water purification system (Merck, Kenilworth, NJ, USA) with a resistivity of 18.2 M\(\Omega  
Ljungby, Sweden) and the mass range of the 5975C MS was set to 35-400 _m/z_. All data handling was performed and exported using the _Data analysis_ software in _Chemstation_ (Agilent Technologies), and identification with mass spectrometry was done with the National Institute of Standards and Technology (NIST) MS Search 2.0 program for the NIST/Environmental Protection Agency (EPA)/National Institute of Health (NIH) Mass Spectral Library version 2.0 g, build 2009.  
Peak detection was performed by using the integration function in _Chemstation_ data analysis software. In the method for peak detection, the parameters were set to initial area reject of 1,500,000, initial peak width of 0.02, shoulder detection off, and initial threshold of 16.0. For determination of the total area in the chromatogram, the parameters of the integration method were set to initial area reject of 1, initial peak width of 0.02, shoulder detection off, and initial threshold of 15.0. Retention indices were calculated by comparison of the retention times to that of the 49452-U C\({}_{7}\)-C\({}_{40}\) alkane standard (Supelco, Bellefonte, PA, USA) (10 \(\upmu\)g of each in hexane), and external standard identification was performed by comparing the sample analyte peak retention times to that of the retention times of compounds present in the CRM40755 Cannabis Terpene Mix A (Sigma Aldrich) (10 \(\upmu\)g of each in hexane). The mix contained the following 20 terpenes: \(\upalpha\)-pinene, \(\upbeta\)-pinene, camphene, 3-carene, \(\upalpha\)-terpenine, R-(+)-limonene, \(\upgamma\)-terpinene, L-(\(-\))-fenchone, fenchol, (1R)-(+)-camphor, isoborneol, menthol, citronello, (+)-pulegone, geranyl acetate, \(\upalpha\)-cedrene, \(\upalpha\)-humulene, nerololid, (+)-cedrol, and (\(-\))-\(\upalpha\)-bisabolol. The standards of \(\upbeta\)-caryophyllene standard 22075 (Sigma-Aldrich) and the (\(-\))-caryophyllene oxide 91034 (Sigma-Aldrich) were also used to confirm the identity of the detected compounds. Analysis parameters, peak detection parameters and peak selection were based on the work by [PERSON] et al. (2018).  
All statistical analysis and graphical work were performed in the Rstudios R software. Source code, libraries required, and data tables are provided in the Supplementary Materials.