Functional morphology of the sting apparatus of the spider wasp Cryptocheilus versicolor (Scopoli, 1763) (Hymenoptera: Pompilidae)

Abstract

The females of the spider wasps (Hymenoptera: Pompilidae) hunt spiders to provision their larvae. The genital structures of pompilid females are modified in a sting that is used for paralyzing the prey (spiders) and defense. The skeleto‐muscular structure of the sting apparatus of a typical representative of the family (Cryptocheilus versicolor) is examined. The shape of sclerites, their relative positions and articulations are described. Some morphological adaptations are described for the first time. The wide anal arc of the tergum IX provides a stiff support for the muscles that move the valvulae. The resilin structures in the areas of articulation support the work of muscles and in some cases replace them. The 1st valvulae form a venom duct along their entire length, which provides the delivery of the venom to a specific point. An unpaired flap in the venom duct provides a dose of venom in the sting. This mechanism probably enhances the speed and accuracy of the wasp's sting movements. Functions of muscles and interactions of the structures of the sting apparatus of C. versicolor are discussed.

Comparative morphology of the musculature of the sting apparatus in Ampulex compressa (Hymenoptera, Ampulicidae) and Sceliphron destillatorium (Hymenoptera, Sphecidae)

“…The evolution of the ovipositor into the sting apparatus is evident in the high number of homologous muscles explained below. The homologies between the sting apparatus of Chrysidoidea (Barbosa et al 2021) and the species described herein can be tracked comparing both to the pompilid Cryptocheilus versicolor (Kumpanenko and Gladun 2018). Chrysidoidea is the sister group to the monophyletic taxon containing Pompiloidea and Apoidea, within which Pompiloidea occupies a relatively basal position.…”

“…Comparisons of the stinger and sclerites (Fig. 1B, D) to the illustrations of Kumpanenko and Gladun (2018, fig. 6c) as well as Matushkina (2011, fig.…”

“…1D). A high density of chemo-and mechanoreceptors on the posterior tip of the third valvula suggests that the posterior third remains on the stinger while being extended, presumably to guide the stinger (Matushkina 2011, Kumpanenko andGladun 2018). While an extended stinger is of little consequence for the comparison of muscles by origin and insertion, it does allow for an insight into the process of stinging.…”

“…Barbosa et al (2021) published the latest work on the sting apparatus of Chrysidoidea, which is the most basal taxon of Aculeata. Both recent publications of Kumpanenko and Gladun (2018) and Barbosa et al (2021) do not describe the musculature connecting the sting apparatus to the cuticle, though.…”

“…Apart from older studies (Snodgrass 1933, Trojan 1935, Rietschel 1937, examination of the musculature of the sting apparatus has been largely neglected. More recently, Kumpanenko and Gladun (2018) published a study on the musculature and sclerites of the sting apparatus of Cryptocheilus versicolor (Pompilidae). Barbosa et al (2021) published the latest work on the sting apparatus of Chrysidoidea, which is the most basal taxon of Aculeata.…”