Chemical distances based on CHC analyses
New CHC extractions were performed following Peña-Carrillo et al.
(2021a). We used the Bray-Curtis distances as dissimilarity measures to
calculate chemical distances between the 156 examined specimens based on
the relative abundances of the simplified chemical profile. This was
obtained by summing the percentages of hydrocarbons with the same
carbon-chain length by class (Peña-Carrillo et al. 2021a). We then
calculated the chemical distance between populations (centroids) and
used them to obtain a hierarchical cluster dendrogram using the program
Primer 6 & Permanova + (Anderson 2017). We also performed Mantel tests
based on Pearson’s product-moment correlation, running analyses with a
maximum of 999 permutations to correlate chemical, genetic and
geographic distances among the examined populations. Mantel tests were
performed with the Vegan package (Oksanen et al. 2015) in R Studio
(Version 3.5.2).