A MORPHOMETRIC STUDY OF STING GLANDS IN VESPID WASPS (HYMENOPTERA, VESPIDAE)

A morphometric study of sting glands was performed in 25 species of 10 genera of polistine social wasps. An attempt was made to find among-s pecies patterns of differentiation in the proportions of these glands. The morphometric variables measured were: length of venom gland filam ents, length of venom reservoir, width of venom reservoir, length of m ain venom duct, length of Dufour's gland, and length of sting's stylet . The six variables were correlated with body size across species. In the performed principal component analysis, 85.5% of the among-species variance was explained by the first component, which was clearly asso ciated with size variation. Dufour's gland length had the lowest corre lation with the first principal component, and was the most important variable on the second component. This indicates that overall size is less important in determining average proportions of Dufour's gland in polistine species. Parachartergus pseudapicalis was morphologically t he most deviant species, with a very small Dufour's gland and relative ly longer venom gland filaments. Preliminary results for solitary eume nine species indicate different trends for some variables of the gland ular system.