Suillia variegata (Loew, 1862)

Rotheray, Graham E., 2012, Morphology of the puparium and breeding sites of eight species of Heleomyzidae (Diptera), Journal of Natural History 46 (33 - 34), pp. 2075-2102 : 2092-2094

Suillia variegata

Puparium. Length 4–5 mm (n = 4), length of second abdominal segment 0.4 mm, red-brown in ground colour; dorsal transverse striae well developed across the middle of abdominal segments 1–7 ( Figure 1C ); locomotory spicules numerous and variable in size and mostly tapered ( Figure 8B ); spicule band circumventing body segments and continuing to the dorsal surface of segments 1–7 but spicule bands wider on segments 5–7 than on segments 1–4; rosette-shaped anterior spiracles with 10 respiratory bulbs ( Figure 3G ); projections bearing posterior spiracular plate orange basally, black above, about as wide at base as at apex and about as long as basally wide; spiracular plates separated by about twice the width of a spiracular plate; spiracular plate ( Figure 5A ), smooth-rimmed, without indentations or a projection between spiracular slits 1 and 2; posterior spiracular slits long, longer than the diameter of the ecdysial scar; head skeleton ( Figure 11A,D ), length 1.3 mm; mandible without a pin-hole window but with small accessory teeth at base of hook; base of mandible subrectangular in profile shape and lower margin parallel with that of the basal sclerite; intermediate sclerite comma-shaped with ventral bridge at the middle ( Figure 11D ); epipharyngeal plate heavily sclerotized; dorsal cornu narrower than ventral cornu with most sclerotization at base; vertical plate sclerotized posteriorly and reaching dorsal apodeme on the ventral cornu; vertical plate long, longer than the intermediate sclerite.

Material examined. Scotland, Perthshire, Tomanbludhe, NN7359, three puparia ex root of marsh thistle, Cirsium palustris , tunnelled by syrphid larvae ( Diptera : Syrphidae ), root collected 13 May 2004, heleomyzid puparia discovered in decaying material, adults emerged 7–9 June 2004, KP Bland; Scotland, Midlothian, Temple, Braidwood, NT3158, one puparium, ex old seedheads of ramsons, Allium ursinum , seedheads collected 10 June 2007, adult emerged in the period 24 June to 15 July 2007, KB Bland.

Additional rearing record. One adult: Berkshire, Farnham Royal, ex nest of a robin, Erithacus rubecula , nest at ground level in a hedge, nest collected 24 May 1931, adult found dead in nest 2 January 1932, EB Basden.

Taxonomic notes

With the addition of the puparium of S. laevifrons ( Figures 3H , 5C , 8C , 11B,E ) described previously by Bland and Rotheray (1996), the puparia of the three suillines are similar and distinguished from other heleomyzids studied here by the intermediate sclerite with a central ventral bridge and rosette-shaped anterior spiracles. The puparium of S. ustulata is easily separated from that of the other suillines by the irregular, not rectangular shaped, base of the mandible, the blunt-tipped locomotory spicules on the ventral surface and the dorsum of abdominal segments 1–4 with wide bands of spicules, covering about half of each segment. Suillia laevifrons is readily distinguished by the yellow not black projections supporting the posterior spiracular plates and the corrugated, not smooth margin to the posterior spiracular plate, the relatively few locomotory spicules on the ventral surface and their absence dorsally. Suillia variegata is distinguished by the presence of wider bands of spicules on the dorsum of abdominal segments 5–7 than on segments 1–4, the reverse of S. ustulata .

Figures

Figure 1. Heleomyzidae, whole puparia, lateral view, anterior end to the left, dorsal margin uppermost, (A) Heteromyza rotundicornis, length 5 mm, (B) Heleomyza borealis, length 6 mm, (C) Suillia variegata, length 4 mm.

Figure 3. Heleomyzidae, anterior spiracles, lateral view, scale bar 0.1 mm, fan shape: (A) Eccoptomera microps, (B) Scoliocentra brachypterna; transverse rosette shape: (C) Heleomyza borealis, (D) Tephrochlamys flavipes, (E) Tephrochlamys tarsalis, (F) Heteromyza rotundicornis; rosette shape: (G) Suillia variegata, (H) Suillia laevifrons, and (I) Suillia ustulata.

Figure 5. Suillinae, posterior spiracles, apical view, scale bar 0.1 mm, (A) Suillia variegata, (B) Suillia ustulata, (C) Suillia laevifrons.

Figure 8. Suillinae, locomotory spicules, across mid-ventral zone of the posterior margin of the second and the anterior half of the third abdominal segment, uppermost vertical line indicates the mid-ventral point, horizontal line indicates approximate segment boundary, (A) Suillia ustulata, (B) Suillia variegata, (C) Suillia laevifrons.

Figure 11. Suillinae, head skeletons, uppermost figures, whole structure, lateral view, mandible to the right, lower figures, dorsal view of intermediate sclerite and mandible in that order, scale bar 0.25 mm, (A, D) Suillia variegata, (B, E) Suillia laevifrons, (C, F) Suillia ustulata.