Microdon myrmicae Schonrogge
Creators: name: Scarparo, Giulia
name: Wolton, Robert
name: Molfini, Marco
name: Pinna, Luigi Cao
name: Ulio, Andrea Di Gi-
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae
Microdon
Microdon myrmicae

description: Immature stages of Microdon myrmicae
Egg
Figs 1, 11
Width = 587.4 ± 36.61 µm; length = 1.08 ± 0.03 mm (n = 10).
First instar larva
Figs 2−6, 11, Supplementary Material 1
Body width = 679.5 ± 55.42 µm; body length = 0.996 ± 0.08 mm (n = 10). Body features. Body with regularly rounded sides. Four longitudinal grooves present dorsally (Fig. 2A) dividing dorsal body surface into five main longitudinal fields: one medial, two lateral and two external fields. Medial field partially divided into two halves by a longitudinal, medial line. Dorsal surface with regularly spaced “flower-like” sensilla (Figs 3A, E): medial field with two longitudinal rows of nine sensilla; each lateral field with 13 sensilla arranged in two rows (seven along lateral groove and six along medial groove); each external field with one row of 10 sensilla. Each sensillum (Fig. 3E) composed of a cylindrical base, with many imbricate, thick sculpticels, apically with a medial flower-like structure with a variable number (5–10) of long lobes, pointed at tip, encircling a medial dome. Ventral surface covered medially by pointed microsculpture, finely pilose on sides. Ventral flower-like sensilla (Figs 3C, G) similar to dorsal ones except for flat, soft, unsculptured base and flat, thin, distinctly pointed lobes. Pseudocephalon. Two pairs of sensorial organs on dorsal surface of pseudocephalon (Figs 4E, G), one anterior (Fig. 4E) and one posterior (Fig. 4G), each composed of clusters of four short and one long trichoid sensilla emerging from bulbous, hollow base. Posterior spiracular tubercle. Impair respiratory structure, elongated in shape; surface of spiracular tubercle with peculiar microsculpture, completely covered by imbricate, sclerotised scales with an irregularly indented apex (Fig. 5A). Apex of tubercle with two circular smooth plates, slightly convex (Fig. 5C). Marginal band. Distinctly long fringe, length of processes regularly varying, showing eight waves on each side (Figs 2A, E, 6A, C, E). Each individual process composed of an elongate stem and an apical fringed brush (Figs 6A, C, E); the stem showing two very different surfaces: dorsal surface apparently articulated with 4–5 imbricated joints, the distal one fringed apically (Figs 6A, E); ventral surface completely smooth (Fig. 6C).
Third instar larva
Figs 7−9, 11
Body width = 4.5 ± 0.7 mm; body length = 6.1 ± 0.8 mm (n = 10). Dorsal reticulation. Dorsal reticulation reduced to a narrow, lateral belt around the perimeter of abdomen (Figs 7A, B). Each reticulation process showing sub circular groups of 5–9 umbrella-like structures with a flattened, circular apex (Figs 7A, B). Posterior spiracular tubercle. Dome shaped with two round holes spaced 1.2 times as long as their diameter; apex divided into two halves (Figs 8A, B) by a narrow furrow showing irregular plates. Marginal band. Processes on the marginal band short and thick, set close to one another, parallel, radially projecting, with suboval basal “joints”, not imbricated, the last one produced into a flat medial brush. Processes on the marginal band of three types (Figs 9A, B): type one basally 4–jointed and apically single and flat, with medial brush 2–lobed; type two basally 3–jointed and apically bifurcate, with medial brush 1–lobed; type three basally 3–jointed and apically produced into a group of three spiniform setae. Type one and type two regularly alternating in sequence, type three irregularly present between two type one processes.
Puparium
Figs 10, 11
Body width = 6.1 ± 0.5 mm; body length = 7.9 ± 0.7 mm (n = 10). Anterior spiracular tubercles. Length of each tubercle about 1.4 times as long as wide, conical, tapering at the apex (Fig. 10A, B), smooth at the base, with the apex furrowed by about 150 respiratory fissures (Figs 10A); each fissure laying on a small papilla (Fig. 10B).
description: Published as part of Scarparo, Giulia, Wolton, Robert, Molfini, Marco, Pinna, Luigi Cao & Ulio, Andrea Di Gi-, 2020, Comparative morphology of myrmecophilous immature stages of European Microdon species (Diptera: Syrphidae): updated identification key and new diagnostic characters, pp. 348-370 in Zootaxa 4789 (2) on pages 354-357, DOI: 10.11646/zootaxa.4789.2.2, http://zenodo.org/record/3990836