Julia Skimmer, Orthetrum julia, Julia-skepper
Julia Skimmer, Orthetrum julia, Julia-skepper is fairly large sized and robust with a brownish to bluish, weakly mottled and striped thorax, and a light blue abdomen.
Developments from DNA testing:
- DNA testing has shown inconclusive differences between O. julia falsum and O. julia capicola.
- This has led to a theory of colour variations of the same species.
- Orthetrum julia was previously sub-divided into tow sub-species:
- Orthetrum julia falsum Julia Skimmer ( Northern form) (present in the eastern and northern areas of South Africa). May currently be describes as Julia Skimmer Northern Form
- Orthetrum julia capicola Cape Skimmer (Cape form or Southern form) (present in the southern and eastern Cape areas of South Africa) May currently be describes as Julia Skimmer Southern Form
- This page will discuss Julia Skimmer (Northern form), Orthetrum Julia falsum.
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Key identification features:
- Length 38 - 44 - 46mm, wingspan 60 - 68 - 74mm, pterostigmas. 3 - 3.5mm
- Face light grey. Labium cream with central dark brown spear shape that reaches front margin in the northern form but not in the Cape form. Labrum is light grey with a black edge in the northern form or all cream in the Cape form.
- Eyes dark turquoise.
- Thorax mottled brownish with blue pruinescence, bluish green shoulder stripe present, thorax can become all pruinescent blue in individuals occurring in swamp forests of northern KwaZulu-Natal; thorax lighter in Cape form with two light greyish blue side stripes, which are not pruinescent. Long pruinescent stripe present between wing bases. Metepimeral carina marked with black line
- Wings clear, becoming smoky with age, especially at tips. Small dark brown splashes present at bases of the wings, especially hindwings. Costas greenish (diagnostic) Pterostigmas blackish brown to black in the northern form, reddish brown in Cape form (3.1–3.5 mm long).
- Abdomen of medium build, all pruinecent blue (S 7- 10 may be dark disappearing with age)
- Striped, all light and dark brown, tends to be pinkish in Cape form.
- Foliations strong, black.
- Thorax heavily striped all over in northern form.
- Abdomen segments 1 to 6 alternately striped, segments 7 to 10 almost entirely blackish (may have light brown spots on both sides of dorsal carina.)
- Wings clear to heavily smoky in some old individuals of Cape form.
- Pterostigmas dark brown to blackish
- Northern form occurs in dappled shade in thick bush or forest over pools or still reaches of rivers. The Cape Skimmer or Southern form prefers more open habitats, even large treeless pools, and still reaches of rivers.
- From 0 to 2500 m above sea level, but mostly below 1600.
- It is conspicuous as it perches in woodlands, forests or gardens, darting fast after prey or to chase an intruder.
Compared with other species:
- Pterostigmas: Orthetrum julia falsum, Julia Skimmer is the only Orthetrum with blackish pterostigmas. Much lighter, reddish brown on O. J. capicola
- Thorax stripe: Three species with distinctive thorax stripes Orthetrum Caffrum, Two-stripped Skimmer, has a cream stripe between wings.
Light blue in O. J, Capicola. O. chrysostigma has a single, distinctive creamish stripe on each side of the thorax (at least when young),
whereas O. j. capicola has two, indistinct bluish stripes
- Recorded throughout much of SA. Colour variations are now noted in the northern ECP due to possible interbreeding between the northern and Cape variations.
- Angola; Benin; Botswana; Burkina Faso; Burundi; Côte d'Ivoire; Cameroon; Central African Republic; Congo-Brazzaville; Democratic Republic of the Congo; Equatorial Guinea; Eritrea; Ethiopia; Gabon; Gambia; Ghana; Guinee-Bissau; Kenya; Liberia; Malawi; Mozambique; Namibia; Nigeria; Republic of Guinea; Republic of South Africa; Rwanda; São Tomé & Príncipe; Sierra Leone; Socotra (Yemen); Somalia; South Sudan; Sudan; Swaziland; Tanzania; Togo; Uganda; Zambia; Zimbabwe;