Austroplebeia australis

Dollin, Anne E., Dollin, Leslie J. & Rasmussen, Claus, 2015, Australian and New Guinean Stingless Bees of the Genus Austroplebeia Moure (Hymenoptera: Apidae) — a revision, Zootaxa 4047 (1), pp. 1-73 : 44-45

Austroplebeia australis –Eastern Colour Morph

Diagnosis. As in general diagnosis of A. australis with the following exceptions:

Worker HBW 0.33–0.39 mm ( Fig. 11 ). Most workers have the following characteristics: thorax markings Grades 2–5 ( Figs 5 , 7 ), ventral scape dark brown, upper edge of pronotal collar maculations limited to two small lateral spots, apical terga brown ( Fig. 9 ), leg maculations limited to a basal spot on tibia I. Male HBW 0.25–0.29 mm, HTW 0.46–0.54 mm ( Fig. 13 ). Distribution QLD and NSW ( Fig. 28 c).

Description. As in general Austroplebeia description, except for the following characters.

Worker. Body 3.4–4.4 mm. Forewing (including tegula) 3.8–4.6 mm. All other measurements are listed in Table 3 .

Structure. Head width 1.67–1.92 mm, 1.2x head length. Interocellar distance 1.5–1.9x ocellorbital distance. Clypeus length 0.5–0.6x width. Malar area 0.2–0.3x basal mandibular width. Mandible preapical teeth more widely spaced than in A. cincta ( Fig. 17 f). Scape length 0.7–0.8x alveolus–lateral ocellus distance.

Scutellum length 0.3–0.5x width. Wing venation similar to that shown in Figs 18 a, d. First transverse cubital vein vestige (up to 75 Μm) present in 35% of wings examined ( Fig. 18 c) and slight trace in 54% (n=138). Vein M of forewing terminates at or before position of anterior end of first recurrent vein in 97% of wings examined (n=138). Cell second Cu of forewing completely indicated by pigmented vein traces (n=137). Hamuli 5 to 7 per wing. HBW moderately broad ( Figs 11 , 19 h), 0.33–0.39 mm.

Sting rudiments. Gonostyli shoulder width broad, 0.13–0.17 mm. Apex of sting stylet usually broadly rounded. Sting lancet length moderately long, 0.25–0.34 mm ( Figs 15 , 16 d).

Colour. Face markings usually Grades 2–3a, ranging 1–3a ( Figs 1 , 3 ). Thorax markings usually Grades 2–4, ranging 0–11 ( Figs 5 , 7 ), Grade 2 maculations: 12% brown, 88% cream.

Other areas with cream or yellow markings: usually pronotal lobe and a basal spot on tibia I; sometimes labrum, upper edge of pronotal collar (usually limited to two small lateral spots) and a spot on tegula.

Labrum ranging red-brown to cream. Scape usually dark brown to red-brown. Flagellum ranging dark brown to yellow-brown. Tegula ranging dark brown to yellow-brown, sometimes with a cream spot. Basal and medial terga usually black to orange-brown. Apical terga usually brown, ranging dark brown to yellow-brown ( Fig. 9 ). Sterna ranging black to yellow-brown. Unmarked areas of tibia I dark brown to brown.

Pilosity. As in A. essingtoni , with the following differences:

Plumose hair on paraocular area and supraantennal area longer than on clypeus, well-branched and dense, hiding most of the surface. Clypeus with finer plumose hair that reveals more of surface and rarely obscures upper margin of clypeus ( Fig. 22 d). Vertex bristles 75–225 Μm.

Scutum longer simple hairs 100 Μm, lateral and anterior fringes 175–225 Μm. Scutellum bristles 100–275 Μm. T6 simple hairs up to 175 Μm.

Penicillum and rastellum bristles golden, sometimes pale gold or slightly brown. Basitarsus III inner surface evenly covered with coarse golden bristles, sometimes pale gold or slightly brown.

Geographic variation. The extent of thorax colour markings in the Eastern Colour Morph was generally 3– 10% ( Fig. 10 ), with most relatively dark populations occurring in southeastern QLD.

Worker bees with mixed characteristics were found between the ranges of the Eastern and Central Colour Morphs ( Fig. 28 c), generally having more extensive thorax markings (10–17%) but with HTW/HBW scores within the Eastern Colour Morph range.

In a few colonies, workers and males had distinctive orange abdomens, similar to those seen in many Central Colour Morph colonies ( Fig. 26 ) e.g. Nest Q35, Eulo, QLD, and NSW15, Kempsey, NSW.

An isolated colony on the tip of Cape York, QLD, (F31) had workers resembling the Eastern Colour Morph in structure and colouration. However, it differed from other Eastern Colour Morph colonies by a relatively high 6 bps in our 16S mDNA molecular analysis (Halcroft and Dollin unpublished data) and may be genetically distinct. This colony was separated from other Eastern Colour Morph colonies by a large population of Central Colour Morph colonies on lower Cape York ( Fig. 28 c).

Male. Body 3.9–4.8 mm. Forewing (including tegula) 4.1–4.5 mm. All other measurements are listed in Table 5 .

Structure. Head width 1.76–1.87 mm. Interocellar distance 2.1–2.6x ocellorbital distance. Clypeus length 0.6– 0.7x width. Mandible preapical tooth weaker than in A. cincta ( Fig. 17 k). Scape length 0.7–0.8x alveolus–lateral ocellus distance. Flagellum relatively longer than in A. cincta , flagellum length 4.2–4.5x scape length. Hamuli per wing 5–6. HBW broad, 0.25–0.29 mm. HTW broad, 0.46–0.54 mm ( Fig. 13 ). HTL long, 1.14–1.32 mm ( Fig. 14 ).

Terminalia and genitalia. Graduli of S3 and S4 gently curved. S5 gradulus transverse and usually very close to or touching antecosta, pregradular area slightly wider in some Eastern Colour Morph males, apical margin smooth or slightly curved. S6 with median body width variable but relatively broad and parallel sided or with slight medial constriction, apically pointed. S7 quadrangular, apical margin transverse ( Figs 20 c, i, m, q). Gonostylus gently curved. Base of penis valve relatively broad and short (similar to Figs 21 c, e).

Colour. Face markings usually Grade 17, sometimes 15–16 ( Figs 2 , 4 ). Thorax markings usually Grade 6 or 11, sometimes 10 or 12 ( Figs 5 , 8 ).

Other areas with cream or yellow markings: ventral scape, labrum, mandible, upper edge of pronotal collar except medially (sometimes just two spots), pronotal lobe, apical terga, usually sterna and basitarsi, and sometimes a spot on tegula. Most femora and all tibiae with cream areas.

Scape red-brown dorsally, yellow-brown to cream ventrally. Flagellum dark brown to brown. Tegula redbrown to yellow brown, sometimes with a cream spot. Metanotum ranging black to yellow-brown. Basal terga usually dark brown to orange-brown. Apical terga yellow-brown or cream ( Fig. 9 ). Sterna ranging dark brown to cream. Unmarked areas of tibiae dark brown to brown.

Pilosity. As in A. essingtoni with the following differences:

Face simple hairs, ca. 100 Μm. Vertex bristles, 100–275 Μm. Scutum with numerous ca. 50 Μm and sparse ca. 100 Μm simple hairs, up to 225 Μm laterally. Scutellum simple hairs, up to 300 Μm. Mesepisternum plumose hairs usually broad and triangular, with long, evenly spaced barbs basally and a long tip ( Fig. 25 e). T7 hairs, up to 325 Μm.

Surface sculpture. As in A. essingtoni .

Queen. Body 5.5–6.9 mm. Forewing (including tegula) 4.0– 4.6 mm.

Structure. HBW 0.23–0.30 mm.

Colour. Face markings up to Grade 7 ( Fig. 24 c). Thorax markings up to Grade 13.

Pilosity. Clypeus with sparse to moderate fine hair, mostly simple. Scutellum bristles gold to slightly brown and up to 500 Μm. T1–T5 with sparse fine short hairs, sparse longer (up to 375 Μm) coarse bristles on lateral and dorsal surfaces of T2–T5. T6 with short dense hair and an apical fringe of long (up to 375 Μm) simple hairs. Basitarsus III inner surface bristles golden.

Figures

FIGURE 1. Face colour marking grades used to classify Austroplebeia workers. In many specimens, these cuticle markings may be obscured by hair on the clypeus and paraocular area. Visualisation of these markings can be improved by tilting the bee's head back and viewing the face obliquely.

FIGURE 2. Face colour marking grades used to classify Austroplebeia males.

FIGURE 3. Variation in worker face colour grades observed within all Austroplebeia taxa except A. cincta. Data show 300 workers from 114 colonies, in addition to 50 workers from 10 flower samples of A. australis – Western Colour Morph. Colour grades are as illustrated in Fig. 1.

FIGURE 4. Variation in male face colour grades observed within all Austroplebeia taxa except A. cincta and A. australis – Western Colour Morph. Data show 186 males from 38 colonies. Colour grades are as illustrated in Fig. 2.

FIGURE 5. Thorax colour marking grades used to classify workers and males of Austroplebeia.

FIGURE 7. Variation in worker thorax colour grades observed within all Austroplebeia taxa except A. cincta. Data show 2503 workers from 158 colonies, in addition to 59 workers from 15 flower samples of A. australis – Western Colour Morph. Colour grades are as illustrated in Fig. 5.

FIGURE 8. Variation in male thorax colour grades observed within all Austroplebeia taxa except A. cincta and A. australis – Western Colour Morph. Data show 196 males from 38 colonies. Colour grades are as illustrated in Fig. 5.

FIGURE 9. Variation in colour of the clypeus, mandible (middle part) and apical terga in workers and males of all Austroplebeia taxa. (No males are known in A. cincta NG and A. australis – Western Colour Morph.) Data are based on 120 workers and 62 males.

FIGURE 10. Ratio of head width and extent of thorax colour marking in workers of all Austroplebeia taxa except A. cincta. Data from 121 colonies are shown, in addition to five flower samples from A. australis – Western Colour Morph and one A. australis flower sample with mixed Western / Central characteristics. Data points are averages from 10 – 49 workers per colony, or 5 – 12 workers per flower sample. Data from eight individual type specimens are also shown. The T. symei and T. ornata types, in which the eyes are collapsed preventing accurate head width measurement, are not shown. The T. essingtoni holotype has a missing head, so data from the paratype are shown. 1. Colony F 31 from the northern tip of Cape York Peninsula, QLD, which has characteristics similar to A. australis – Eastern Colour Morph despite its geographic isolation. Names given in brackets in the legend are groups in our Halcroft et al. (2015) preliminary analysis.

FIGURE 11. Ratio of tibia III width and basitarsus III width in workers of all Austroplebeia taxa. Data from 173 colonies are shown, in addition to 26 flower samples: A. australis – Western Colour Morph (14 x), A. australis with mixed Western / Central characteristics (4 x) and NG A. cincta (8 x). Data points are averages from 2 – 4 workers per colony, or 1 – 12 workers per flower sample. Data from 12 individual type specimens are also shown. 1. Colony F 31 from the northern tip of Cape York Peninsula, QLD, which has characteristics similar to A. australis – Eastern Colour Morph despite its geographic isolation. Names given in brackets in the legend are groups in our Halcroft et al. (2015) preliminary analysis.

FIGURE 13. Ratio of tibia III width and basitarsus III width in males of all Austroplebeia species. Data points are averages from 2 – 3 males per colony. Data from the male paratypes of A. magna sp. nov. are also shown. Names given in brackets in the legend are groups in our Halcroft et al. (2015) preliminary analysis.

FIGURE 14. Ratio of head width and tibia III length in males of all Austroplebeia species. Data points are averages from 2 – 3 males per colony. Data from the male paratypes of A. magna sp. nov. are also shown. Names given in brackets in the legend are groups in our Halcroft et al. (2015) preliminary analysis.

FIGURE 15. Worker sting rudiments metric data: ratio of maximum length of sting lancet (A) and shoulder width of gonostyli (B) in all Austroplebeia taxa. Data points are averages for 1 – 3 workers per nest or flower sample. 1. The geographically isolated colony, F 31, from the northern tip of Cape York Peninsula, QLD, which has colouring and HTW / HBW similar to A. australis – Eastern Colour Morph. 2. Colonies C 58 and D 55 from the ‘ intermediate’ group of Halcroft et al. (2015) which are consistent with A. australis – Eastern Colour Morph in this analysis. 3. CS- 8 workers, with Grade 4 Thorax Colour Markings, collected from flowers in the MacDonnell Ranges, NT. They are consistent with A. australis – Central Colour Morph in this analysis, despite their relatively dark colouration. 4. GS- 10 workers collected from flowers on the far western edge of the A. cassiae range. 5. NS- 7 workers collected from flowers on the far eastern edge of the A. magna sp. nov. range. Names given in brackets in the legend are groups in our Halcroft et al. (2015) preliminary analysis.

FIGURE 16. Austroplebeia worker sting rudiments: a, A. cincta NG; b. A. cincta QLD; c, A. essingtoni; d, A. australis – Eastern Colour Morph; e, A. australis – Central Colour Morph; f, A. australis – Western Colour Morph; g, A. cassiae; h, A. magna sp. nov. All drawn to same scale. Abbreviations: Gon—gonostylus; Sty—sting stylet (bulb); Lan—sting lancet (first valvula or first ramus).

FIGURE 17. Austroplebeia antennae, mandibles and labial palpi. Figs a – c. Antenna (basal part) of A. essingtoni: a, worker; b, male; c, queen. Figs d – h. Left mandible of worker: d, A. cincta QLD; e, A. essingtoni; f, A. australis; g, A. cassiae; h, A. magna sp. nov. Figs i – m. Left mandible of male: i, A. cincta QLD; j, A. essingtoni; k, A. australis; l, A. cassiae; m, A. magna sp. nov. Fig. n. Left mandible of A. australis queen. Figs a – n drawn to same scale. Figs o – q. Labial palpus of worker (mesal margins uppermost, small hairs omitted): o, A. cincta; p, A. cassiae; q, A. magna sp. nov. Figs o – q drawn to same scale. Abbreviations: F 1 — first flagellomere; F 2 — second flagellomere; F 3 — third flagellomere; F 2 L—second flagellomere length (showing how this measurement was made).

FIGURE 18. Austroplebeia wings. Dotted lines indicate pigmented vein traces. Figs a – c. Forewings, showing variation observed in the vestige of the first transverse cubital vein: a, A. magna sp. nov. forewing with a short vein vestige; b, Detail of an A. australis – Eastern Colour Morph forewing with a thickening of vein M at this position; c, Detail of an A. australis – Eastern Colour Morph forewing with a long vein vestige. Fig. d. Hindwing of A. magna sp. nov. Fig. e. Diagram of a forewing showing how the following measurements were made: (1) forewing length without tegula; (2) forewing width; (3) wing diagonal (Sakagami 1978); (4) 1 st abscissa of M length; (5) 1 st abscissa of Cu length. Figs a – d drawn to same scale: scale bar = 0.25 mm. Abbreviations: M—vein M; 1 st R—first recurrent vein; 2 nd Cu—second cubital cell; Ham—hamuli.

FIGURE 19. Austroplebeia legs. Figs a – b. Worker tibia III and basitarsus III of A. australis – Central Colour Morph: a, inner surface; b, outer surface. Fig. c. Cross-sectional view of A. australis worker tibia III, inner surface uppermost. Fig. d. Worker leg II of A. australis – Eastern Colour Morph, showing mesotibial spur near junction of tibia and basitarsus. Figs e – f. Male tibia III and basitarsus III of A. australis – Central Colour Morph: e, inner surface; f, outer surface. Fig. g. Queen tibia III and basitarsus III of A. australis – Central Colour Morph, outer surface. Fig. h. Variation in size of worker basitarsus III (shaded segment), all drawn to same scale: A. cincta QLD is shown on the left, then remaining species are shown in order of increasing basitarsus III width. Abbreviations: Kei—keirotrichia; Pos—posterior corbicular fringe; Ant—anterior corbicular fringe; Rasrastellum; Cor—corbicula; Pen—pencillum.

FIGURE 20. Austroplebeia male sterna and terga, shown in ventral view except for Fig. r. Figs a – f. S 4: a, A. cincta; b, A. essingtoni; c, A. australis; d – e, A. cassiae showing variation in position of gradulus; f, A. magna sp. nov. Figs g – j. S 5: g, A. cincta; h, A. essingtoni, arrow indicates protruding apical lobe; i, A. australis; j, A. cassiae. Figs k – o. S 6: k, A. cincta; l, A. essingtoni; m, A. australis; n, A. cassiae; o, A. magna sp. nov. Figs p – q. S 7: p, A. cincta; q, A. australis. Fig. r. T 7 of A. cassiae, dorsal view. Figs a – f, scale bar = 0.5 mm; figs g – r, scale bar = 0.33 mm. Abbreviations: Gra—gradulus; Med—median body.

FIGURE 21. Austroplebeia male genitalia. Figs a – c. Genitalia, dorsal view on left, ventral view on right: a, A. cincta; b, A. essingtoni; c, A. magna sp. nov. Figs d – e. Apical abdomen and protruding parts of genitalia, viewed laterally, as visible in many pinned male specimens: d, A. essingtoni, showing distinct curve in apical gonostylus; e. A. magna sp. nov., with gently curved apical gonostylus. Figs a – c drawn to same scale. Abbreviations: Pen—penis valve; Gon—gonostylus.

FIGURE 22. Austroplebeia worker faces: a, A. cincta NG; b, A. cincta QLD; c, A. essingtoni, showing a relatively heavily marked specimen within the species range; d, A. australis – Eastern Colour Morph; e, A. cassiae; f, A. magna sp. nov. Scale bars = 0.25 mm.

FIGURE 24. Austroplebeia queen faces: a, A. cincta QLD; b, A. essingtoni; c, A. australis – Eastern Colour Morph; d, A. australis – Central Colour Morph; e, A. cassiae; f, A. magna sp. nov. Scale bars = 0.25 mm.

FIGURE 25. Austroplebeia lateral thoraces: Figs a – b. Worker mesosomal side: a, A. cincta QLD; b, A. cassiae. Figs c – d. Male mesosomal side: c, A. cincta QLD; d, A. cassiae. Figs e – g. Detail of mesepisternum pilosity on male mesosomal side (photographs by K. Walker): e, A. australis; f, A. cassiae; g, A. magna sp. nov. Figs e – g shown at same magnification; all scale bars = 0.25 mm. Abbreviation: Met—metepisternum.

FIGURE 26. An A. australis worker with the distinctive orange abdomen, that is common in western QLD populations (photograph by D. Clarke).

FIGURE 28. Observed distribution of all Austroplebeia species in Australia and the island of New Guinea: a, A. cincta; b, A. essingtoni; c, A. australis; d, A. magna sp. nov. and A. cassiae. In all maps, square symbols represent nest samples and circles represent samples collected from flowers or traps. The type locality for each named species, including those now synonymised, is indicated with arrows. Where the type locality was a general area such as ' Central Australia' or ' Cape York', these areas are indicated with shading.