Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

• Dorsal shield entire with 12–14 pairs of setae; present = (j1, 3, 4, 5, 6; J5; z2, 4, 5; Z1, 4, 5; s4); j5, S5 present or absent (j1 absent on some individuals in cultures).
• Setae r3 and R1 present in the soft cuticle
• Setae Z1, Z4, Z5 and s4 along margin of dorsal shield very long and barbed
• Sternal shield with 2–3 pairs of setae, st4 +/- st3 on small plates
• Anal opening small, on anal (3 setae) or small ventrianal shield (4–5 setae)
• Movable digit of chelicerae with 3 teeth, fixed digit chelate-serrate with 7–9 teeth or more stubby and chelate-dentate with only 3 teeth and terminal hook
• Spermatheca funnel-like, either broadly tapering or with narrow neck and basal swelling
• Tibia I setation: 2–2/2, 2/1–2

Open Phytoseiulus key

Similar taxa

Ascidae mites usually have dorsal shields with 22 or more pairs of setae. Blattisociidae may have have phytoseioid-like corniculi (e.g., Blattisocius), but usually have much fuller dorsal shield setation (Lasioseius phytoseioides group excepted). Most other species of Amblyseiinae have ventrianal shields.

Ecology and distribution

Species of Phytoseiulus are widely established around the world because of their use as biological control agents. They are specialist predators of spider mites that produce dense webbing, especially species of Tetranychus.

References

• Evans and Till 1966Evans and Till 1966:
  Evans GO, Till WM. 1966. Studies on the British Dermanyssidae (Acari: Mesostigmata). Part II. Classification. Bulletin of the British Museum (Natural History) Zoology 14: 107–370.
• Gilyarov and Bregatova 1977Gilyarov and Bregatova 1977:
  Gilyarov MS, Bregatova NG, eds. 1977. Handbook for the identification of soil-inhabiting mites, Mesostigmata. Zoological Institute of the Academy of Sciences, Petrograd.
• Karg 1993Karg 1993:
  Karg W. 1993. Acari (Acarina), Milben Parasitiformes (Anactinochaeta) Cohors Gamasina Leach, Raubmilben. Die Tierwelt Deutschlands 59: 1–523.
• Schicha 1987Schicha 1987:
  Schicha E. 1987. Phytoseiidae of Australia and neighbouring areas. Indira Publishing House, Oak Park, Michigan.
• Schuster and Pritchard 1963Schuster and Pritchard 1963:
  Schuster RO, Pritchard EA. 1963. Phytoseiid mites of California. Hilgardia 43 (7): 191–285.
• Takahashi and Chant 1993Takahashi and Chant 1993:
  Takahashi F, Chant DA. 1993. Phylogenetic relationships in the genus Phytoseiulus Evans (Acari: Phytoseiidae). II. Taxonomic Review. International Journal of Acarology 19: 23–37.
• Tenorio 1982Tenorio 1982:
  Tenorio JM. 1982. Hypoaspidinae (Acari: Gamasida: Laelapidae) of the Hawaiian Islands. Pacific Insects 24: 259–274.
• Tseng 1976Tseng 1976:
  Tseng YH. 1976. Systematics of the mite family Phytoseiidae from Taiwan, with a revised key to the genera of the world (II). Journal of the Agricultural Association of China 94: 86–128.
• Walter and Campbell 2003Walter and Campbell 2003:
  Walter DE, Campbell NJH. 2003. Exotic vs endemic biocontrol agents: Would the real Stratiolaelaps miles (Berlese) (Acari: Mesostigmata: Laelapidae) please stand up? Biological Control 26: 253–269.
• Womersley 1956Womersley 1956:
  Womersley H. 1956. On some new Acarina-Mesostigmata from Australia, New Zealand and New Guinea. Journal of the Linnean Society of London, Zoology 42: 505–599.
• Wright and Chambers 1994Wright and Chambers 1994:
  Wright EM, Chambers RJ. 1994. The biology of the predatory mite Hypoaspis miles (Acari: Laelapidae), a potential biological control agent of Bradysia paupera (Dipt.: Sciardiae). Entomophaga 39: 225–235.
• Zumpt and Patterson 1951Zumpt and Patterson 1951:
  Zumpt F, Patterson PM. 1951. Further notes on laelaptid mites parasitic on vertebrates. A preliminary study to the Ethiopian fauna. Journal of the Entomological Society of Southern Africa 14: 63–93.