Hymenoptera

R. G. Beutel & S. N. Gorb, 2001, Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny, J. Zool. Syst. Evol. Research 39, pp. 177-207 : 182

30 Hymenoptera

Four­ or three­segmented tarsi are found only in a few representatives of Hymenoptera (e.g. Chalcidoidea part., Platygasteridae , Trichogrammatidae ; Naumann 1991). An arolium is generally present ( Figs 2 , 3a , 6F ) and additional, specialized tarsal adhesive thorns in the nonapocritan groups (‘Symphyta’) ( Figs 3i , 6A–C ).

Figures

Fig. 2. Terminology of arolium structures (schematized from Snodgrass 1956). (a) Dorsal aspect; (b) ventral aspect; (c) lateral aspect. ar, arolium; arc, arcus; aux, auxillae; f, marginal flange of the terminal tarsomere; mn, manubrium; pln, planta; tar, tarsal segments; un, claw; ut, unguitractor plate

Fig. 3. Diversity of the leg attachment devices (gray­colored areas) in hexapods. (a) Arolium (smooth). (b) Pulvilli (smooth or hairy). (c) Empodial pulvillus (ep) (hairy). (d) Hairy adhesive soles of tarsomeres. (e) Eversible pretarsal bladder (smooth). (f) Eversible structure between tibia and tarsus (smooth). (g) Fossula spongiosa (hairy). (h) Euplantulae (eu) and claw pad (cp) (both smooth). (i) Tarsal thorns transformed into adhesive structures (th), claw pad (cp) (both smooth). (j) Adhesive claw setae

Fig. 6. Details of hexapod tarsi and pretarsi. (A, B) Urocerus gigas (Hymenoptera), hindleg, tarsus, lateral aspect. (C) Abia seriacea (Hymenoptera), hindleg, ventro­lateral aspect of the single attachment thorn. (D) Panorpa communis (Mecoptera), midleg, pretarsus, ventrolateral aspect. (E) Tipula sp. (Diptera), midleg, pretarsus, ventro­lateral aspect. (F) Apis mellifera (Hymenoptera), midleg, tarsus, ventral aspect. AR, arolium; ARC, arculus; HS, hairy soles; PLN, planta; TAR, tarsal segments; TH, specialized tarsal adhesive thorns; UN, claw; UT, unguitractor plate