Flat Mites of the World


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

5 (+ several new species being described by Beard et al. in prep.)

Raoiella australica, R. eugeniae, R. indica, R. macfarlanei, R. shimpana




Most species occur in Australia (based on Beard et al. in prep.), with others in Greece, India, South Africa.

Raoiella indica has recently spread to the Nearctic, Neotropical and African regions.


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).


  • bright red to dark red, often with black patches, when alive (Figs. 10, 11)
  • eggs red; most species with obvious stipe (Fig. 13)


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).

All known species of Raoiella feed via the stomata of their host plant (Ochoa et al. 2011; Beard et al. 2012).

Several new species are being described by Beard et al. (in prep.).


Fig. 1. Raoiella macfarlanei female dorsum.


Fig. 2. Raoiella species 2A, female dorsal opisthosoma (image: Gary Bauchan, USDA-ARS).


Fig. 3 Raoiella macfarlanei female dorsum (type specimen).


Fig. 4. Raoiella indica female dorsum.


Fig. 5. Raoiella species 8, adult female dorsum.


Fig. 6. Raoiella species 3A, female posterior venter.


Fig. 7. Raoiella species 13, female posterior venter, with detail of genital region (image: Gary Bauchan, USDA-ARS).


Fig. 8. Raoiella sp. female posterior venter, with detail of genital region.


Fig. 9. Raoiella sp. deutonymph, dorsal setae with frozen droplets (image: Gary Bauchan, USDA-ARS).


Fig. 10. Raoiella species - live females; note droplets on tips of setae (R. indica top right).


Fig. 11. Raoiella species 13, live females, male and eggs.


Fig. 12. Raoiella spp. male with modified ps1 seta.


Fig. 13. Raoiella species 8, live eggs with immatures and moulted skins.