Fig. 4

First two dimensions (VAF: percent of variance accounted for) of the CATPCA of the head gland morphology of male Philanthinae. Based on the morphology of their head glands, the species form three distinct groups (ellipses; exemplary 3D-reconstructions: (I) Cerceris quinquefasciata, (II) Philanthus rugosus, (III) Philanthus politus). Triangles: object scores of single species (IDs correspond to Table 1), Vectors: component loadings of morphological characters, Circles: Group centroids of the different phylogenetic and phylogeographic clades (according to [33]) included as a supplementary variable. Note that for each of the two genera Clypeadon (orange) and Philanthinus (red) only one species was included in the analysis, thus, their object scores are identical to their group centroids. Color code: yellow, genus Cerceris; orange, genus Clypeadon; red, genus Philanthinus; purple, Palearctic/Asian Philanthus; blue, Palearctic/Afrotropical Philanthus; light green, Nearctic Philanthus; dark green, genus Trachypus. Abbreviations of morphological characters (numbering corresponds to section 2.4.1): ppg.structure, (1) overall structure of the PPG; ppg.size, (2) size of the PPG relative to the head capsule; ppg.parts, (3) modifications of PPG morphology; ppg.branching, (4) branching of the PPG; ppg.open.lower, (5) numbers of openings of the lower part of the PPG to the pharynx; ppg.wall, (6) structure of the inner walls of the PPG; ppg.type, (7) type of gland cells associated with the PPG; mg.presence, (8) presence of the MG; mg.size, (10) size of the MG relative to the head capsule; mg.branching, (12) branching of the MG; mg.type, (14) type of gland cells associated with the MG