Tenuipalpidae

Pineapple false spider mite Dolichotetranychus floridanus, from here.

Belongs within: Tetranychoidea.
Contains: Tenuipalpus, Brevipalpus, Aegyptobia.

The Tenuipalpidae, false spider mites, are a group of slow-moving phytophagous mites characterised by reduction of the palp and loss of the thumb-claw complex. Some species are economically significant pests. They are most diverse in tropical and subtropical regions though some tropical species have become more widespread in greenhouses (Walter et al. 2009). They have been divided between three subfamilies with the gnathosoma completely covered by the propodosoma and a rostral shield absent in the Tegopalpinae (Smiley & Gerson 1996). Members of the Brevipalpinae have both pairs of intercoxal setae IC3 and IC4 situated on the hysterosoma whereas Tenuipalpinae have IC4 on the hysterosoma and IC3 on the posterior part of the propodosoma (Baker & Tuttle 1987). Within the Tenuipalpinae, members of the genus Ultratenuipalpus possess four-segmented palpi, postanal setae, one pair of anal and two pairs of intercoxal setae (Baker & Tuttle 1987).

False spider mites
Published 26 June 2017

Among the enormous diversity of the world’s mites, some families are particularly notorious for the damage that they inflict on commercial plant crops. Among such Acari non grata are the spider mites of the family Tetranychidae or the gall mites of the Eriophyidae. But a third, equally notorious group is the false spider mites or flat mites of the Tenuipalpidae.

Red and black flat mite Brevipalpus phoenicis, false-colour SEM by Christopher Pooley.

False spider mites include about 800 known species of more or less flattened, slow-moving mites. They are closely related to the true spider mites and both families have the chelicerae modified into a pair of long, whip-like retractable stylets that are used to pierce and suck fluids from plant tissues. In the case of the false spider mites, though, their commercial infamy comes not only from the direct damage caused by the feeding mites themselves but also from the effects of transmitted viruses. Viruses transmitted by false spider mites include the causative agents of diseases such as citrus leprosis and coffee ring spot and may cause significant reductions in the yield and lifespan of infected plants.

Morphologically, false spider mites differ from true spider mites in the absence of what is called the ‘thumb-claw’ process, an arrangement of the tarsus of the pedipalp alongside a claw on the tibia (hence the family name which means ‘slender palp’). The palps are often reduced, with some species having only the barest remnant. Some species also show reduction in the fourth pair of legs, and females of a number of species are six-legged as adults. This merely stands as another example of how mite morphology functions purely to play silly buggers with anything one might learn in basic animal biology.

Hebe stem gall mites Dolichotetranychus ancistrus inside an open gall, copyright Plant and Food Research.

Parthenogenesis is also common in false spider mites. Species found in cooler climes will often overwinter as females, with a new generation of males not appearing until the next spring. In some species, eggs produced parthenogenetically will hatch into males; in others, they will produce females. A few species almost entirely lack functional males. A small group of these species in the genus Brevipalpus is unique among animals in being both parthenogenetic and genetically haploid.

Almost all forms of seed plant seem to be vulnerable to some form of flat mite or another; some mite species are very catholic in their tastes and will latch onto almost anything green and photosynthesising. Others are more discerning. How false spider mites make their way from one host plant to another is little known but they may be passively carried through the air on the wind. Alternatively, they may be inadvertently carried from place to place by feeding herbivores, or by the very human horticulturalists that suffer so much from their presence.

Systematics of Tenuipalpidae

Characters (from Walter et al. 2009): Cheliceral bases fused into movable stylophore, attached to idiosoma by retractable ribbed collar; movable cheliceral digits elongated, whip-like, recurved basally within stylophore. Palp linear, with five or fewer segments and lacking a thumb-claw process. Prodorsum with three pairs of setae (v1 absent), without prodorsal bothridial setae; opisthosoma with at most thirteen pairs of setae dorsally and laterally (c1 usually present, c4 absent, two pairs h setae); anal valves with 1-3 pairs of simple pseudanal setae. Pretarsal claws with tenent hairs.

<==Tenuipalpidae [Phytoptipalpidae, Tenuipalpini]
    |--TenuipalpinaeBT87
    |    |--TenuipalpusBT72
    |    `--Ultratenuipalpus Mitrofanov 1973BT87, H98
    |         |--*U. meekeri (De Leon 1957) [=Tenuipalpus meekeri]BT87
    |         |--U. bunyai Smiley & Gerson 1995H98
    |         `--U. younguisti Baker & Tuttle 1987BT87
    |--TegopalpinaeSG96
    |    |--Tegopalpus Womersley 1940H98
    |    |    `--*T. conicus Womersley 1940SG96
    |    |--Philippipalpus Corpuz-Raros 1978SG96
    |    |    `--*P. agohoi Corpuz-Raros 1978SG96
    |    `--Australopalpus Smiley & Gerson 1995SG96
    |         `--*A. alphitoniae Smiley & Gerson 1995SG96
    `--BrevipalpinaeBT87
         |--BrevipalpusBT72
         |--AegyptobiaBT87
         |--Priscapalpus De Leon 1961BT87, BTA75
         |    |--*P. macropilis De Leon 1961BT87
         |    `--P. cherretti [=*Deleoniella cherretti]BT87
         |--Pseudoleptus Bruyant 1911BT87, BT72
         |    |--*P. arechavaletae Bruyant 1911BT87
         |    |--P. bouteloua Baker & Tuttle 1972BT72
         |    |--P. hilaria Baker & Tuttle 1972BT72
         |    |--P. palustria Pritchard & Baker 1952BTA75
         |    |--P. panicum Baker & Tuttle 1972BT72
         |    |--P. tridens Baker & Tuttle 1972BT72
         |    `--P. zelihaeSG96
         |--Pentamerismus McGregor 1949 [incl. Livshitzia Mitrofanov 1973, Oligomerismus Mitrofanov 1973]BT87
         |    |  i. s.: P. tauricus [=*Livshitzia taurica]BT87
         |    |         ‘Tenuipalpus’ taxi [=*Oligomerismus taxi]BT87
         |    |--P. erythreus groupBT87
         |    |    |--*P. erythreus (Ewing 1917) [=Tenuipalpus erythreus]BT72
         |    |    |--P. abnormis Baker & Tuttle 1987BT87
         |    |    `--P. arbutusae Baker & Tuttle 1987BT87
         |    `--P. oregonensis McGregor 1949BT87
         |--Phytoptipalpus Trägårdh 1904BT87, BP60
         |    |  i. s.: P. aegyptetrapodus [=*Zaheria aegyptetrapodus]BT87
         |    |         P. albizziae Pritchard & Baker 1958BP60 [=*Neophytoptipalpus albizziaeBT87]
         |    |--*P. paradoxus Trägårdh 1904BT87
         |    `--P. cercidium groupBT87
         |         |--P. ceibae (De Leon 1962) [=Aegyptobia ceibae]BT87
         |         |--P. cercidium (Baker, Tuttle & Abbatiello 1975) [=Aegyptobia cercidium]BT87
         |         `--P. conostegiae Baker & Tuttle 1987BT87
         `--Dolichotetranychus Sayed 1938 [incl. Dolichotetranychoides Mitrofanov 1973, Stenotetranychus Mitrofanov 1973]BT87
              |--*D. floridanus (Banks 1900) [=Stigmaeus floridanus, Pseudoleptus floridanus, Trichadenus floridanus]BT87
              |--D. ancistrus Baker & Pritchard 1956BT72
              |--D. apaches Baker & Pritchard 1956BT72
              |--D. australianus (Womersley 1943) [=Trichadenus australianus]H98
              |--‘Siteroptes’ carnea [=*Stenotetranychus carneus]BT87
              |--D. macer Baker & Pritchard 1956BP60
              |--D. muhlenbergia Baker & Tuttle 1972BT72
              |--D. summersi [=D. (*Dolichotetranychoides) summersi]BT87
              `--D. vandergootiWL09
Tenuipalpidae incertae sedis:
  Larvacarus transitansWL09
  Rarosiella cocosaeC-R02
  Obdulia tamaricisWL09
  Obuloides rajamohaniWL09
  Capedulia maritimaWL09
  Raoiellana Baker & Tuttle 1972BT72
    `--*R. allium Baker & Tuttle 1972BT72
  Lisaepalpus Smiley & Gerson 1995H98
    `--L. smileyae Smiley & Gerson 1995H98
  Macfarlaniella Baker & Pritchard 1962H98
    `--M. queenslandica (Womersley 1942) [=Raoiella queenslandica]H98
  Phyllotetranychus Sayed 1938BP60
    |--P. aegyptiacus Sayed 1938 [=P. aegyptium]BP60
    `--P. romaine Pritchard & Baker 1958BP60
  Meyeraepalpus Smiley et al. 1996H98
    |--M. delfinadae Smiley et al. 1996H98
    `--M. strandtmanni Smiley et al. 1996H98
  Raoiella Hirst 1924H98
    |--R. australica Womersley 1940H98
    |--R. indica Hirst 1924BP60
    `--R. macfarlaneiG01
  Crossipalpus Smiley et al. 1996H98
    |--C. creelae Smiley et al. 1996H98
    |--C. muellerianae Smiley et al. 1996H98
    `--C. verticillatae Smiley et al. 1996H98
  TerminalichusSG96
  Tenuilichus Mohanasundaran 1988SG96
  AfronychusSG96
  ColeoacarusSG96
  KrugeriaSG96

*Type species of generic name indicated

References

[BP60] Baker, E. W., & A. E. Pritchard. 1960. The tetranychoid mites of Africa. Hilgardia 29 (11): 455–574.

[BT72] Baker, E. W., & D. M. Tuttle. 1972. New species and further notes on the Tetranychoidea mostly from the southwestern United States (Acarina: Tetranychidae and Tenuipalpidae). Smithsonian Contributions to Zoology 116: 1–37.

[BT87] Baker, E. W., & D. M. Tuttle. 1987. The false spider mites of Mexico (Tenuipalpidae: Acari). United States Department of Agriculture, Technical Bulletin 1706: 1–237.

[BTA75] Baker, E. W., D. M. Tuttle & M. J. Abbatiello. 1975. The false spider mites of northwestern and north central Mexico (Acarina: Tenuipalpidae). Smithsonian Contributions to Zoology 194: 1–23.

[C-R02] Corpuz-Raros, L. A. 2002. Philippine acarine biological control agents: status, bioecology and research prospects. Philippine Agricultural Scientist 85 (2): 137–154.

[G01] Gupta, S. K. 2001. A conspectus of natural enemies of phytophagous mites and mites as potential biocontrol agents of agricultural pests in India. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 484–497. CSIRO Publishing: Melbourne.

[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.

[SG96] Smiley, R. L, & U. Gerson. 1996. Observations on the Tenuipalpidae (Prostigmata) and a new subfamily classification. In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 367–371. Ohio Biological Survey: Columbus (Ohio).

[WL09] Walter, D. E., E. E. Lindquist, I. M. Smith, D. R. Cook & G. W. Krantz. 2009. Order Trombidiformes. In: Krantz, G. W., & D. E. Walter (eds) A Manual of Acarology 3rd ed. pp. 233–420. Texas Tech University Press.

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