Results
Agreement in classification between gaugers
–
The classification of the 18 pairs of independent observations made by
eleven gaugers was successful for the two taxa according to the
cumulative PCA analysis that involved all gaugers’ observations in the
same analysis. Each gauger arrived at the two-species hypothesis with
only two misidentified observations (less than 1%) out of the total 198
(Fig. 3a); a single misclassification appeared in two different gaugers
respectively. The results of the PCA revealed that the species identity
was responsible for the differences based on the morphological traits,
and was not ascribed to gauger effect (Fig. 3b). The PCA results were
based on the inertia 5489, and the variance explained by the 1st axis
was 62.59%, while the variance for the 2nd axis was 10.32%; thus, the
overall explained variance was 72.91%. These patterns were also
revealed by the PERMANOVA performed using the Morosita index of
dissimilarity with 9999 iteration, where the gaugers were shown to have
no significant effect on the species identity based on the measured
morphological traits (R2=0.69, p=0.58).