Raoiella
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Fig. 1. Raoiella macfarlanei female dorsum. |
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Fig. 2. Raoiella karri, female dorsal opisthosoma (image: Gary Bauchan, USDA-ARS). |
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Fig. 3 Raoiella macfarlanei female dorsum (type specimen). |
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Fig. 4. Raoiella indica female dorsum. |
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Fig. 5. Raoiella taronga, adult female dorsum. |
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Fig. 6. Raoiella wandoo, female posterior venter. |
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Fig. 7. Raoiella bauchani, female posterior venter, with detail of genital region (image: Gary Bauchan, USDA-ARS). |
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Fig. 8. Raoiella sp. female posterior venter, with detail of genital region. |
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Fig. 9. Raoiella tallerack deutonymph, dorsal setae with frozen droplets (image: Gary Bauchan, USDA-ARS). |
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Fig. 10. Raoiella species - live females; note droplets on tips of setae (R. indica top right). |
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Fig. 11. Raoiella bauchani, live females, male and eggs. |
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Fig. 12. Raoiella spp. male with modified ps1 seta. |
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Fig. 13. Raoiella taronga, live eggs with immatures and moulted skins. |
Key characters
- full complement of dorsal setae (Figs. 1, 2)
- h2 not elongate
- dorsal setae spatulate
- lateral setae often obviously longer than central setae (Figs. 1-5)
- anterior margin of prodorsum smoothly rounded, without notch or projection
- ventral, genital and anal plates membranous, not developed (Figs. 6-8)
- 2 pairs ps setae (Figs. 6-8)
- 2 segmented palp (Fig. 6)
- droplets of liquid present on dorsal setae, when alive or frozen (Figs. 9-11)
- males with modified ps1 setae, usually thickener and/or longer than ps2 (Fig. 12)
Number of species
23
Authority
Hirst
Distribution
Most species occur in Australia (Beard et al. 2018), with others in Greece, India, South Africa.
Raoiella indica has recently spread to the Nearctic, Neotropical and African regions.
Hosts
Most species are recorded from Myrtaceae, with others recorded on Arecaceae, Celastraceae, Musaceae, Oleaceae.
Raoiella indica is a palm specialist (Arecaceae), but is also found on other monocot hosts including Musa spp. (Musaceae).
Colour
- alive = bright red to dark red, often with black patches; often shiny in appearance (Figs. 10, 11)
- eggs red; most species with obvious stipe (Fig. 13)
Remarks
All known species in this genus produce and carry droplets of an unknown liquid at the tips of its dorsal setae (Figs. 9-11).
A droplet usually also occurs on the tip of the stipe on the egg (Fig. 13), and the female is responsible for placing this droplet on the egg stipe. See:
https://www.youtube.com/watch?v=vV8K1EF7ecA
https://www.youtube.com/watch?v=JhKOFVHXXLA )
All known species of Raoiella feed via the stomata of their host plant (Ochoa et al. 2011; Beard et al. 2012).
