Fig. 2

Oviposition process of Lariophagus distinguendus. a Female wasps search for potential hosts that live in grains of the common wheat Triticum aestivum. b–p Single frames of high-resolution video recordings of a female L. distinguendus parasitizing a larva of Sitophilus granaries in an artificial chamber (cf. Additional file 1). The wasp and the beetle larva were separated by a piece of blotting paper. After the wasp finds a host (b), it brings its terebra into drilling position by a downward bending of the metasoma (c) and then, once the apex of the terebra is engaged in the substrate, it lifts the metasoma and the 3rd valvulae upwards (d). Following penetration of the substrate, the wasp permanently paralyzes the host larva by venom injection and then usually forms a feeding tube for host feeding. During the subsequent assessment of the host and the search for a suitable place for oviposition, the wasp is able to actively bend (e–l) its terebra in various directions and also to rotate it to a certain degree (o). The individual movements of the single valvulae can be observed (m–p). The 1st valvulae is frequently protracted far beyond the apex of the 2nd valvula (marked with an arrowhead in i, k, m, n, o). Finally, an egg is laid (p). Rapid alternating movements of the 1st valvulae can be observed during substrate drilling, host envenomation and egg laying. Abbreviations: 1vv: 1st valvula; 2vv: 2nd valvula; 3vv: 3rd valvula; trb: Terebra