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Rediscovery And Redescription Of Tetranychus Gigas (Acari, Prostigmata, Tetranychidae)

Authors:
Denise Navia at French National Institute for Agriculture, Food, and Environment (INRAE)
Denise Navia
Carlos Flechtmann at University of São Paulo
Carlos Flechtmann
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Tetranychus gigas Pritchard & Baker, 1955 is redescribed from paratypes and from Brazilian speci-mens collected from soybean.
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547
Accepted by Z.-Q. Zhang: 9 Jun. 2004; published: 21 Jun. 2004 1
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Copyright © 2004 Magnolia Press
Zootaxa 547: 1–8 (2004)
www.mapress.com/zootaxa/
Rediscovery and redescription of Tetranychus gigas
(Acari, Prostigmata, Tetranychidae)
DENISE NÁVIA1 & CARLOS H.W. FLECHTMANN2
1Embrapa, Recursos Genéticos e Biotecnologia, Caixa Postal 02372, 70.770-900 Brasilia, DF, Brazil.
navia@cenargen.embrapa.br
2CNPq-Brasil Researcher, Universidade de São Paulo – ESALQ, Departamento de Entomologia, Fitopatolo-
gia e Zoologia Agrícola, 13418-900 Piracicaba, SP, Brazil. chwflech@carpa.ciagri.usp.br
Abstract
Tetranychus gigas Pritchard & Baker, 1955 is redescribed from paratypes and from Brazilian speci-
mens collected from soybean.
Key words: Acari, Tetranychidae, Tetranychus gigas, redescription, Brazilian fauna
Introduction
The family Tetranychidae, the spider mites, comprises one of the most specialized groups
of plant feeding mites. Some spider mites infest a wide range of plant hosts while others
appear to be rather host specific. They have a unique ability to disperse and exploit new
feeding sites very quickly. For this reason they can inflict severe effects on agricultural and
horticultural crops, often resulting in economic losses.
In the present paper we report the rediscovery of Tetranychus gigas Pritchard & Baker,
1955 and redescribe the species.
T. gigas was first described from 2 males and 6 females collected from cotton from
Sahuarita, Arizona, USA, and 12 males and 36 females from cotton from Crosby County,
Texas, USA. The only additional report on this species is from Tuttle, Baker & Abbatiello
(1974) who reported T. gigas from Parthenium incanum HBK from Torreon, Mexico.
Baker & Tuttle (1994) provided the botanical name of the host plant of the type material as
Gossypium hirsutum (upland cotton). The occurrence of T. gigas on Cucurbita sp. given in
Bolland et al. (1998) is probably a mistake.
NÁVIA & FLECHTMANN
2 © 2004 Magnolia Press
547
ZOOTAXA Our material is one male from cotton, Sahuarita, Arizona, USA and 8 females from
cotton, Crosby County, Texas, USA, paratypes, located at Departamento de Entomologia,
Fitopatologia e Zoologia Agricola, Universidade de São Paulo/ESALQ, Piracicaba, SP,
Brazil; 6 males and 15 females from soybean, Glycine max L. cultivar 7001, Canguçu, Rio
Grande do Sul, Brazil; 5 males, 15 females from soybean cultivar 8001, from Tronqueiras,
Rio Grande do Sul, Brazil. The Brazilian specimens from soybean did not differ from the
paratypes.
Measurements are given in micrometers.
Tetranychus gigas Pritchard & Baker
Tetranychus gigas Pritchard & Baker, 1955:405.
Redescription
FEMALE (n = 18) — Idiosoma 368–563 long, 555–675 including rostrum, 280–431
wide. Colour in life carmine red.
Prodorsal striation longitudinal; opisthosomal striae longitudinal between setae e1 and
e1and again between setae f1 and f1, forming a diamond shaped pattern. Peritremes dis-
tally hooked. (Fig. 1).
Palp tarsus: terminal eupathidium (spinneret) 6 long and 4.5 in diameter; two lateral
eupathidia 6 and 7 long; solenidion 6 long. (Fig. 7).
Prodorsal setae slender, barbed; length v2 64–79, sc1 124–158, sc2 94–113. Distances
between setal insertions: v2–v2 60–75, sc1–sc1 83–94. Hysterosomal setae long, pubes-
cent. Setal length: c1 116–150, c2 113–143, c3 101–124, d1 113–139, d2 113–139, e1
113–131, e2 113–143, f1 98–128, f2 79–101, h1 38–49. Distances between setal insertions:
c1–c1 56–79, d1–d1 98–109, e1–e1 113–131, f1–f1 34–75.
Legs: tarsus I with proximal duplex setae located at level (Fig. 4) or about level (Fig.
5) with the four proximal tactile setae. Empodia of tarsi I–IV with a small mediodorsal
spur, visible in a perfect lateral view, less than one third the length of the proximoventral
hairs. (Figs. 8–11).
Leg chaetotaxy, from coxae to tarsi (solenidia in parentheses; numbers in brackets rep-
resent an alternative setal count observed in a few specimens)
I — 2-1-9[10]-5-9(1)-13(1) + 2 duplexes
II — 2-1-7[6]-5-7[8]-13(1) + 1 duplex
III — 1-1-4-4[3]-7-9(1)
IV — 1-1-4[3]-4-7-10(1)
Ventral idiosoma transversely striated; area immediately anterior to genitalia with longi-
tudinal broken striae. (Fig. 6).
© 2004 Magnolia Press 3
TETRANYCHUS GIGAS
547
ZOOTAXA
FIGURE 1: Tetranychus gigas Pritchard & Baker, female. Dorsal view.
50 µm
NÁVIA & FLECHTMANN
4 © 2004 Magnolia Press
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ZOOTAXA
FIGURES 2–5: Tetranychus gigas Pritchard & Baker, female. 2. Tibia and tarsus I; 3. Tibia and
tarsus II; 4. Basal part of tarsus I showing proximal duplex seta perfectly in line with four proximal
tactile setae; 5. Basal part of tarsus I with duplex seta lying in a tangent with an immaginary cir-
cumsegmental ring through bases of proximal tactile setae.
10 µm
50 µm
© 2004 Magnolia Press 5
TETRANYCHUS GIGAS
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FIGURES 6–11: Tetranychus gigas Pritchard & Baker, female. 6. Genitoanal region; 7. Palp tibia
and tarsus; 8–11. Tarsal appendages of legs I–IV, in this sequence.
20 µm 20 µm
NÁVIA & FLECHTMANN
6 © 2004 Magnolia Press
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ZOOTAXA
FIGURES 12–19: Tetranychus gigas Pritchard & Baker, male. 12. Tibia and tarsus I; 13. Tibia and
tarsus II; 14–17. Tarsal appendages of legs I–IV, in this sequence; 18. Palp tibia and tarsus; 19.
Aedeagus.
10 µm
20 µm
20 µm
10 µm
© 2004 Magnolia Press 7
TETRANYCHUS GIGAS
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ZOOTAXA
MALE (n = 10) — smaller than female, 366–484 long, including rostrum. Palptarsus
terminal eupathidium (spinneret) 5 long and 2.6 in diameter; two lateral eupathidia 5 and 6
long; solenidion 4.5 long. (Fig. 18).
Leg chaetotaxy, from coxae to tarsi (solenidia in parentheses)
I — 2-1-10-5-9(4)-13(2) + 2 duplexes
II — 2-1-6-5-7-13(1) + 1 duplex
III — 1-1-4-4-6-9(1)
IV — 1-1-4-4-7-10(1)
Empodium I with a strong proximoventral, tapering tooth and, on each side, with a
finer tooth on each side; mediodorsal spur strong and nearly as long as the trifid append-
age. Empodium II with a strongly developed mediodorsal spur; empodia III and IV each
with the mediodorsal spur small but obvious. (Figs. 14–17).
Aedeagus shaft short, gradually narrowing and turning dorsad at a wide (obtuse)
angle, ending in a larger knob. A neck is virtually absent. Aedeagal knob about as long as
dorsal margin of shaft with the anterior angulation acute and caudal angulation acutely
curved ventrad. Dorsum of knob rounded (Fig. 19). Pritchard & Baker (1955) describe and
figure a longer dorsal margin of the aedeagal shaft, however in the paratype specimen as
well as in the Brazilian specimens we examined is much shorter.
We also examined one female and one male of a Tetranychus collected from beans,
Phaseolus vulgaris L., in Piracicaba, São Paulo, Brazil, 5 Nov. 1971, coll. O. Nakano,
which is considered to be very close to T. gigas. The male aedeagus is undistinguishable
from that of T. gigas, but its tibia II has only 6 setae and tarsus IV 9 setae and one solenid-
ion. The female is similar to that of T. gigas in the general aspect, differing in having 6
setae on tibia III and mainly in the much longer dorsal opisthosomal setae: c1 225, c2 210,
c3 195, d1 225, d2 210, e1 206, e2 210, f1 180, f2 105 and in the wider distances between
their bases: c1–c1 113, d1–d1 165, e1–e1 101 and f1–f1 105. Tarsal appendages have also
the same aspect as those of T. gigas.
Acknowledgements
We are grateful to Ronald Ochoa and Debra Creel, United States Department of Agricul-
ture, for information on the type material, and to J.V.C. Guedes, Universidade Federal de
Santa Maria, Rio Grande do Sul, Brazil for collecting and submitting the specimens from
soybean.
References
Baker, E.W. & Tuttle, D.M. (1994) A Guide to the Spider Mites (Tetranychidae) of the United
States. Indira, Michigan, 347 pp.
NÁVIA & FLECHTMANN
8 © 2004 Magnolia Press
547
ZOOTAXA Bolland, H.R., Gutierrez, J. & Flechtmann, C.H.W. (1998) World Catalogue of the Spider Mite
Family (Acari: Tetranychidae). Brill, Leiden, 392 pp.
Pritchard, E. & Baker, E.W. (1955) A revision of the spider mite family Tetranychidae. Pacific
Coast Entomological Society Memoirs, 2, 1–472.
Tuttle, D.M., Baker, E.W. & Abbatiello, M. (1974) Spider mites from northwestern and north cen-
tral Mexico (Acarina: Tetranychidae). Smithsonian Contributions to Zoology, 171, 1–18.
... Records of mites associated with soybean in Brazil were obtained from reports in the literature (Guedes et al. 2007;Leite et al. 2003;Návia & Flechtmann 2004;Neto et al. 2008;Oliveira et al. 2007;Roggia et al. 2008Roggia et al. , 2009Oliveira 2010;Vivan et al. 2011 (Fig. 1, Table 1), and also by new samplings carried out in the Cerrado region ( Fig. 1, Table 2). The new records were obtained by 2 samplings carried out in 10 fields during part of the rainy season in Brazil (Nov andDec/2009, andJan/2010). ...
... Diet: Same as M. planki. Tetranychus gigas Pritchard & Baker, 1955 Previous records in Brazil: Rio Grande do Sul: Canguçu, Santa Maria (Návia & Flechtmann 2004, Guedes et al. 2007), Alegrete, Nonoai, Santa Maria, São Pedro do Sul, Victor Graeff (Roggia et al. 2008). Diet: Same as M. planki. ...
View
... Records of mites associated with soybean in Brazil were obtained from reports in the literature (Guedes et al. 2007;Leite et al. 2003;Návia & Flechtmann 2004;Neto et al. 2008;Oliveira et al. 2007;Roggia et al. 2008Roggia et al. , 2009Oliveira 2010;Vivan et al. 2011 (Fig. 1, Table 1), and also by new samplings carried out in the Cerrado region ( Fig. 1, Table 2). The new records were obtained by 2 samplings carried out in 10 fields during part of the rainy season in Brazil (Nov andDec/2009, andJan/2010). ...
... Diet: Same as M. planki. Tetranychus gigas Pritchard & Baker, 1955 Previous records in Brazil: Rio Grande do Sul: Canguçu, Santa Maria (Návia & Flechtmann 2004, Guedes et al. 2007), Alegrete, Nonoai, Santa Maria, São Pedro do Sul, Victor Graeff (Roggia et al. 2008). Diet: Same as M. planki. ...
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... There are intensely green coloured areas around the base of the dorsal setae, and their translucent eggs are arranged along the leaf veins (Moraes and Flechtmann 2008). In Brazil, it is reported to be associated with common bean (Phaseolus vulgaris L.) (Moraes and Flechtmann 1981), cotton (Gossypium sp.) (Costa and Corrêa 1960) and soybean (Glycine max L,) (Flechtmann 1975; Navia and Flechtmann 2004; Roggia et al. 2008). It is commonly associated with soybeans and weeds in the state of Rio Grande do Sul (Navia and Flechtmann 2004; Johann et al. 2009; Klock et al. 2011). ...
... In Brazil, it is reported to be associated with common bean (Phaseolus vulgaris L.) (Moraes and Flechtmann 1981), cotton (Gossypium sp.) (Costa and Corrêa 1960) and soybean (Glycine max L,) (Flechtmann 1975; Navia and Flechtmann 2004; Roggia et al. 2008). It is commonly associated with soybeans and weeds in the state of Rio Grande do Sul (Navia and Flechtmann 2004; Johann et al. 2009; Klock et al. 2011). Some authors suggest that this mite has no economic importance (Moraes and Flechtmann 2008), and it generally does not require any control by farmers. ...
Life history of Phytoseiulus macropilis (Acari: Phytoseiidae) feeding on Mononychellus planki (Acari: Tetranychidae) on common bean leaves (Phaseoulus vulgaris L.)
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Mononychellus planki (Tetranychidae) is a phytophagous mite present mainly on common bean, soybean and cottonweeds in Central and South America. Phytoseiulus macropilis (Phytoseiidae) is a predatory mite commonly associated with tetranychid populations in South and Southeast Brazil. This study tested the hypothesis that M. planki is an alternative prey enhancing the survival of P. macropilis when Tetranychus urticae is absent in the environment. Initially, we determined the predator’s food preference, and then evaluated the biology of P. macropilis studied on M. planki as prey. In food preference experiments, P. macropilis was given a choice between leaf discs with eggs of T. urticae or M. planki. For biology studies, common bean leaf discs were cut and placed on moistened filter paper in plastic plates. Our results suggest that M. planki is a suitable food for P. macropilis on native vegetation and in soybean crops in Rio Grande do Sul, Brazil.
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The objective of this work was to study the occurrence and geographic distribution of phytophagous mites associated to soybean in Rio Grande do Sul, Brazil. Samplings were performed from January to May 2005 on genetically modified soybean (glyphosate-tolerant) crops, in 27 municipalities of six regions - Alto Vale do Uruguai, Campanha, Depressão Central, Planalto Médio, Missões and Serra do Sudeste. Five phytophagous mite species belonging to the family Tetranychidae - Mononychellus planki, Tetranychus desertorum, T. gigas, T. ludeni and T. urticae - occurred in 21, 12, 5, 3 and 14 municipalities, respectively. A map of Rio Grande do Sul with the geographic distribution of each species is presented, as well as an illustrated dichotomous key to help the identification of the spider mites found.
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In Brazil, soybean Glycine max (L.) Merril crops are subjected to incidence of several pests, which are mainly insect species. However, the occurrences of other pest species are growing. In this context, outbreaks of phytophagous mites are becoming more frequent. Nevertheless, records of mites in such crop are available only for Maranhão, Mato Grosso, Minas Gerais and Rio Grande do Sul states. Thus, this work gathers all information published about the diversity of mites found in soybean in Brazil, and also new records of mite species made on samplings taken from the central Cerrado area. In the whole, occurrence of 44 species of plant mites in soybean has been recorded in Brazil. Data from prior studies and the results of this work present the tetranychid Mononychellus planki (McGregor) as the mite species most frequently occurring in the Brazilian soybean crops. A large portion of Phytoseiidae species has occurred in crops from Rio Grande do Sul state. In addition, spontaneous soybean has hosted almost half of the phytoseiid species sampled in Cerrado region. High diversity of Tarsonemidae has been found in the cultivated soybean. More studies about soybean mites are needed to clarify the damage potential of phytophagous mites and the biological role of predatory mites in this crop.
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During the last growing seasons, high infestations of phytophagous mites were observed in the State of Rio Grande do Sul, Brazil, becoming necessary to apply pesticides for their control. The objective of this study was to identify phytophagous and predatory mite species associated with soybean in ten counties of that state, during the 2002/03 and 2003/04 growing seasons, in five soybean cultivars (A 6001 RG, A 7001 RG, A 8000 RG, A 8100 RG, Anta 82), all genetically modified. In samples of soybean leaves four phytophagous mite species (Mononychellus planki (McGregor), Polyphagotarsonemus latus (Banks), Tetranychus desertorum Banks and Tetranychus gigas Pritchard & Baker) and two predatory mite species (Phytoseiulus fragariae Denmark & Schicha and Typhlodromalus aripo De Leon) were found. T. desertorum was found for the first time associated with soybean in the country. Phytoseiulus fragariae and T. aripo are reported for the first time on soybean. The potential of phytoseid mites as biological control agents in soybean crop was discussed. Among the hypotheses to explain the increasing infestation of soybean fields with phytophagous mites area are the progressively larger cultivated area, the dry spells observed in the last few years in the growing season, changes in soybean cropping system that led to increased use of pesticides and utilization of new soybean cultivars with morphological or biochemicals characteristics that favour the development of these mite populations.
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A Guide to the Spider Mites (Tetranychidae) of the United States
  • Jan 1994
  • pp
  • E W Baker
  • D M Tuttle
Baker, E.W. & Tuttle, D.M. (1994) A Guide to the Spider Mites (Tetranychidae) of the United States. Indira, Michigan, 347 pp.