Ampulex compressa (Fabricius, 1781)

Willsch, Maraike, Friedrich, Frank, Baum, Daniel, Jurisch, Ivo & Ohl, Michael, 2020, A comparative description of the mesosomal musculature in Sphecidae and Ampulicidae (Hymenoptera, Apoidea) using 3 D techniques, Deutsche Entomologische Zeitschrift 67 (1), pp. 51-67 : 51

Ampulex compressa (Fabricius, 1781)

Mesothorax.

Second mesopleuro-mesocoxal muscle (pl2-cx2b; Fig. 5C, D, E, G, H ) is slimmer than in Sphex . It arises from the mesopleural spiracle apodeme, fuses with pl2-cx2 (Fig. 5A, C, D, G, H ), and inserts dorsolaterally on the mesocoxa. Lateral mesofurco-mesotrochanteral muscle (fu2l-tr2) is absent. Median mesofurco-mesotrochanteral muscle (fu2m-tr2; Fig. 5B, D, E ) is larger than in Sphecidae , arises from the ventral surface of the mesofurcal arm, and inserts medially on the mesotrochanteral apodeme.

Metathorax.

Anterior metapleuro-metabasalar muscle (pl3a-ba3; Fig. 5C, E ) arises from the metapleuron, posterior to the mesepimeral ridge, and inserts on the metabasalare. This muscle is shorter than in Sceliphron , as it originates farther up. The paracoxal ridge is not very distinct. Posterior mesonoto-metanotal muscle (t2p-t3; Fig. 5A-D, F ) arises from the upper sclerite of the mesoscutellum and inserts on the lower surface of the mesoscutellum; rectangular. There is no filament connecting it to another structure. Anterolateral metapleuro-metanotal muscle (pl3la-t3; Fig. 5B, E, F ) mainly arises anterolaterally from the metafurcal arm (touching pl3-tr3 and partly fu3-tr3, which originate on the posterior surface of the metafurcal arm) and partly from the metapleuron and inserts on the metanotum. Posterolateral metapleuro-metanotal muscle (pl3lp-t3; Fig. 5C, D ) arises from the metapleuron fuses with pl3la-t3, which is covered dorsally by pl3lp-t3, and inserts on the metanotum. It is larger than in Sceliphron and Sphex and fan-shaped. Ventral metapleuro-third axillary sclerite of hind wing muscle (pl3v-3ax3; Fig. 5A, E ) arises from the posterior surface of the mesepimeral ridge. This slim muscle is fused with pl3d-3ax3 and inserts on the third axillary sclerite of the hind wing. Metapleuro-metasubalar muscle (pl3-sa3; Fig. 5C, D ) arises from the metapleuron at the posterior face of the mesepimeral ridge, and inserts on the metasubalare. Lateral metapecto-metafurcal muscle (pc3l-fu3; first description; Fig. 5C, E, G, H ) the slender muscle arises anterior to the metacoxa laterally from the metapectus, and inserts on the posterior surface of the paracoxal ridge. Metafurco-metacoxal muscle (fu3-cx3; first description; Fig. 5C, G, H ) arises medially from the metafurcal arm, fuses with fu3l-cx3, and inserts medially on the metacoxa; it is slender and flattened. The median metafurco-metacoxal muscle (fu3m-cx3; Fig. 5A, F ) arises posteromedially from the metafurca and from the metadiscrimenal lamella and inserts medially on the metacoxa. The lower metafurcal area runs further cranial and offers more posterior space filled by this muscle. Lateral metafurco-metacoxal muscle (fu3l-cx3; Fig. 5B, D ) arises from the metapectus and inserts dorsolateral on the metacoxa. Metasterno-metacoxal muscle (s3-cx3) is absent. Metapleuro-metatrochanteral muscle (pl3-tr3; Fig. 5D, E ) arises posteriorly from the metafurcal arm, which merges into a spiracle at that position. The muscle is positioned laterally of fu3-tr3, fuses with it and inserts on the metatrochanteral apodeme. Metapleural apodeme and paracoxal ridge weakly developed (Fig. 6C, D ); metapleural apodeme fused with lateral metafurcal arms (Fig. 6D ).

Second abdominal segment.

Median mesophragmo-metaphragmal muscle (ph2m-ph3) is absent. The mesophragma in Ampulex is rectangular like the outer cuticle and lacks a posterior notch for the insertion of a muscle. Metaphragmo-second abdominal tergal muscle (ph3-T2; Fig. 5A-C, F ) arises from the metaphragma and propodeum, inserts dorsally on the second abdominal tergite; broad, large muscle extended to the posterior region. Metafurco-second abdominal sternal muscle (fu3-S2; Fig. 5A ) arises posteriorly from the metafurcal arm, positioned posteromedial to fu3-tr3, inserts anteroventrally on the second abdominal sternite. In length and width distinctly more gracile than in Sceliphron . Metasterno-second abdominal sternal muscle (s3-S2; Fig. 5A ) arises from the metadiscrimenal lamella and inserts on the anterolateral margin of the second abdominal sternite. It is noticeably smaller and neither fan-like nor bent, as in Sceliphron .

Figures

Figure 5. The mesosomal musculature of Ampulex compressa divergent to Sphecidae; volume rendering, transparent exoskeleton. A-C anterior to the right; D-H anterior to the left. A. Medial view, all relevant muscles visible from the centre; B. Medial view on submedial muscles; C. Medial view, further lateral located muscles; D. All relevant muscles discernible from lateral view; E. Muscles located sublateral, lateral view; F. Muscles located further medial, lateral view; G. All newly identified muscles (plus pl 2 - cx 2), lateral view; H. Dorsolateral view on all newly identified muscles (plus pl 2 - cx 2). Abbreviations: sp 1 occ - anterior thoracic spiracle occlusor; ism 1,2 - ba 2 - intersegmental membrane-mesobasalar; pl 2 - t 2 b - second mesopleuro-mesonotal; sp 3 occ - posterior thoracic spiracle occlusor; s 2 - cx 2 - mesosterno-mesocoxal; pl 2 - cx 2 - mesopleuro-mesocoxal; pl 2 - cx 2 b - second mesopleuro-mesocoxal; fu 2 - cx 2 - mesofurco-mesocoxal; fu 2 m-tr 2 - median mesofurco-mesotrochanteral; pl 3 a-ba 3 - anterior metapleuro-metabasalar; t 2 p-t 3 - posterior mesonoto-metanotal; pl 3 la-t 3 - anterolateral metapleuro-metanotal; pl 3 lp-t 3 - posterolateral metapleuro-metanotal; pl 3 v- 3 ax 3 - ventral metapleuro-third axillary sclerite of hind wing; pl 3 - sa 3 - metapleuro-metasubalar; pc 3 l-fu 3 - lateral metapecto-metafurcal; fu 3 - cx 3 - metafurco-metacoxal; fu 3 l-cx 3 - lateral metafurco-metacoxal; fu 3 m-cx 3 - median metafurco-metacoxal; pl 3 l-cx 3 - lateral metapleuro-metacoxal; fu 3 - tr 3 - metafurco-metatrochanteral; pl 3 - tr 3 - metapleuro-metatrochanteral; ph 3 - T 2 - metaphragmo-second abdominal tergal; T 1 - S 2 - propodeo-second abdominal sternal; fu 3 - S 2 - metafurco-second abdominal sternal; s 3 - S 2 - metasterno-second abdominal sternal. Scale bars: 0.7 mm (A-C), 0.8 mm (D, E), 0.6 mm (F-H).

Figure 6. Comparison of the paracoxal ridge (pcr) and metapleural apodeme (pl 3 a). A. Sceliphron destillatorium, anterolateral view, head left; B. Sphex lucae, anterolateral view, head left; C. Weakly developed structures in Ampulex compressa, lateral view, head left; D. Ampulex compressa, paracoxal ridge, lateral metafurcal arms (fu 3 a) fused with reduced metapleural apodeme, anterior view. Further abbreviations: pl 3 lp-t 3 - posterolateral metapleuro-metanotal muscle, pl 3 - tr 3 - metapleuro-metatrochanteral muscle, fu 3 - tr 3 - metafurcor-metatrochanteral muscle. Scale bars: 0.4 mm (A-C), 0.3 mm (D).