Stigmaeidae (Acari), the largest family within Raphignathoidea and are well recognized predators against the phytophagous mites and other small soft bodied insects. A survey was conducted to explore the predatory mite fauna from Punjab-Pakistan and a species of the genus Agistemus was collected and described. The drawings and measurements of different body parts were made with the help of an ocular grid and the specimen were compared with the already world described species. Ceremonial description, illustration of main body parts, host range and comparison remarks are also given. Sixteen (16) paratype (females) were collected from different localities of Jhang and Toba Tek Singh (Punjab). All specimens were deposited in the Acarology Research Laboratory, Department of Entomology, University of Agriculture, Faisalabad, Pakistan.

Keywords: acari, new species, predatory mite, agistemus, stigmaeidae

Mites are microscopic organisms which comprise a large group of Arthropod belonging to subclass Acari of the class Aracnida. Mites belonging to family Stigmaeidae constitute a large cosmopolitan cluster of almost 500 species grouped into 32 valid genera including the genus Agistemus considering as the richest one having 85 described species.¹ The genus Agistemus are considered good predators against plant feeding mite families like Tenuipalpidae, Eriophidae and Tetranychiidae and also known to feed on the eggs of white-flies and scale insects.^2-6 The genus Agistemus was erected by Summers ⁷ based on type species Caligonus terminalis Quayle, 1912. Ehara⁸ described Agistemus summersi and Agistemus lobatus from Japan. Gonzales⁹ reviewed the genus Agistemus and prepared a key comprehensively for all species up to (1965) and added 16 new species. Major research contributions in systematics and biology of stigmaeid mites were made by Oudemans,¹⁰ Baker and Wharton,¹¹ Wood,¹² Summers,¹³ Wood,¹⁴ Chaudhri et al.,¹⁵ Yousaf et al.,¹⁶ Chaudhri and Akbar,¹⁷ Gupta,¹⁸ Yue et al.,¹⁹ Siqin et al.,²⁰ Fan and Liu,²¹ Fan et al.,²² Fan & Walter,²³ Devis et al.,²⁴ Faraji & Ueckermann.²⁵ Meyer^26,27 described 3 new species from South Africa and also transferred Zetzellia subreticulata Wood^28,29 to this genus. Chaudhri et al.³⁰ described 4 new species from Pakistan and prepared the Key of these species. Siqin et al.²³ added one new species in the genus Agistemus from China. The goal of this publication was to search the biological control agents for phytophagous mites from Punjab, Pakistan.

Family Stigmaeidae Oudemans¹⁰

Type genus: Stigmaeus Koch³¹

Chelicerae not fused together, Palptibial claw well developed, accessory claw present. Palptarsus with sensillum trifid. Seta vi absent, Eyes 1 pair; Postocular bodies, 1 pair; Dorsal setae, 12 pair; Dorsal shields; 1 propodosomal, 1 median, Intercalary plates obvious, Median shield having 5 pairs of setae. Paragenital setae 1-2 pair, Ventral Idiosoma with 3-4 setae, h3 absent.

Mite of the genus Agistemus (Agistemus layyahensis) Stigmaeidae:³² Acari were collected from the leaves of bitter gourd (Momordica charantia) by adopting sieve collection method. Permanent slides were prepared by using Hoyer’s medium and the identification/ description of species was done with the help of phase contrast microscope. Grandjean’s system of terminology³³ with modifications and additions made by Summer⁷ and Gonzalez⁹ has been used in this work. All the measurements are presented in micrometres (µm) and the measurements of the holotype are followed by ranges of the paratypes in parentheses.

Agistemus layyahensis n.sp.

Adult female Dorsum: (µm)

Body robust 338 long without gnathosoma (335-340), 280 wide (276-283), chelicera 95 long (92-98), stylets 48 (46-50), tibial claw well developed, accessory claw present, palp tarsalpeg equal in length with tibial claw having 2 setae, tip without trifid sensillum (Fig. 1A). Main dorsal shield in completely reticulated. Area immediately behind median propodosomal shield without transverse striations (Figure 1). Metapodal shield not wider as propodosomal shield. Eyes 1 pair, postocular bodies large covers the setal area between sci and sce. Seta c2 is present but without any platelet. Twelve 12 dorsal setae minutely barbed on entire shaft. Seta e2 longer than all dorsal setae; ratio length/distance separating setae of pair ve=1.50 (1.48-1.52); Seta sci equal in length with the distance sci-sce. The ratio c1/c1-c1=1.80 (1.77-1.83); c1-c1 shorter than e1-e1; seta d1 equal with d1-e1. Seta d1 closer to e2 than e1; seta d2 smaller than d2-e2; seta f1 single pair present on very pointed shape intercalary platelets; a band of few striations passing within the intercalary shield and area of seta h1 and h2 without any striations; Seta h2 is shorter than seta h1; ratio h1/h2=1.50 (1.48-1.53). Mesal setae of genu I no longer than its segment length. The respective length of dorsal setae were calculated and given here with their ranges in parenthesis; ve 38 (37-39), sci 75 (72-77), sce 44 (42-46), c2 55 (52-58), c1 52 (51-53), d1 65 (63-67), e 60 (59-61), d2 64 (63-65), e2 72 (70-73), f1 60 (58-62), h1 58 (57-59), h2 40 (38-41).

Figure 1 Dorsal of Agistemus layyahensisn.sp.

Venter

Ventral gnathosomal sub-capitulum with only one pair of seta m and seta n is absent, two pairs of sub terminal adoral setae or1 & or2, seta elcp on subcapitulum not visible, Ventral idiosoma provided with 4 setae (1A-4A) without conspicuous platelets. 2 pairs of paragenital setae and 3 pairs of smooth anogenital setae (Figure 2).

Figure 2 Ventral of Agistemus layyahensis n.sp.

Legs

Legs are slightly vary in their respective length and specialized setae like elcp, ὼ, ῤ, k and Ø not included in the setal numbers. Setae and solenidia are collectively counted on legs I-IV as Figure 3 coxae 0-1-1-1; trochanters 2-2-1-1; femora 2-2-1-0; genua 3-0-0-0; tibiae 3-4-4-4 and tarsi 7-6-6-4 (Figure 4).

Figure 3 Legs I-IV of Agistemus layyahensis n.sp.

Figure 4 Dendrogram of 11 species of the genus Agistemus (Stigmaeidae: Acari) from Punjab, Pakistan.

Etymology

This new species is named on locality name from where it was collected from Punjab, Pakistan.

Adult male

Unknown.

Type

Holotype female collected from bitter gourd crop from the area of 283-Layyah and deposited in acarology research laboratory, Department of Entomology, University of Agriculture, Faisalabad, Pakistan. Sixteen (16) paratype (females) were collected from Jhang & TT Singh on cotton and bitter gourd crop respectively.

Key to genus agistemus form Punjab, Pakistan

1. Main shield reticulated; ventral opisthosoma without platelets; coxa IV with 1 seta………..………………………………………………………….. impavidus Chaudhri
2. Main shield not reticulated, ventral opisthosoma with platelets; coxa IV with 2 setae………………..……………………………………………….…………………….. 2
3. Postocular body small; ratio ve/ve-ve more 3 (3.60); ratio sci/sci-sce = 2.70 ………………………………………….………………………………mirabilis Chaudhri
4. Postocular body large; ratio ve/ve-ve < 3; ratio sci/sci-sce less than 2.00 …………………………………………………………………………………………….3
5. Ratio ve/ve-ve = 2.40; coxa III with 1 seta; mesal seta on genu I shorter than segment length ..……………………………………………………………..……yunusii Chaudhri
6. Ratio ve/ve-ve < 2; coxa III with 2 seta; mesal seta on genu I not shorter than segment length…………...………………………………………………………...……………….4
7. Seta h2 absent; propodosomal shield broader than metapodal shield; genu I & II with 3 and 1 setae respectively..………………………………………...………buntex Chaudhri
8. Seta h2 present; propodosomal shield not broader than metapodal shield; genu I & II not provided with 3 and 1 setae respectively.………………………..……………………… 5
9. Femur I provided with 5 setae; femur II provided with 4 setae; tibia II with 4 setae .………………………....………………………….……………….…..garrulus Chaudhri
10. Femur I not provided with 5 setae; femur II not provided with 4 setae; tibia II less than 4 setae …………….…………………....……………..……………………………………. 6
11. Ventral gnathosoma with more than 3 pairs of setae; ventral idiosoma with complete striations; tibia-III with 6 setae ……………………………………………………...rafiqii
12. Ventral gnathosoma not provided with more than 3 pairs; ventral idiosoma not with complete striations; tibia-III not with 6 setae..……………………………………..……. 7
13. Palp peg with 2 setae; ventral idiosoma with 4 pairs of setae; paragenital setal length not equal; anogental setae with 3 pairs; coxa I without seta ……………………………...………………………..…………………layyahensis (n.sp.)
14. Palp peg not with 2 setae; ventral idiosoma not with more than 3 pairs of setae; paragenital setal length equal; anogental setae not with 3 pairs; coxa I provided with 2 seta ………………………..………………………...………………………………….... 8
15. Palptarsus shorter than main claw; propodosomal shield triangular in shape; dorsal setae comparatively thick; postocular body present ………………… ………………………………….……………………….………………..rawalpindiensis
16. Palptarsus not shorter than main claw; propodosomal shield not triangular in shape; dorsal setae not thick; postocular body absent .……………………………………….…. 9
17. Trifid sensillum present; propodosomal shield provided with pores; palpfemur with 1 seta; seta h1 absent; trochanter II provided with 2 setae…… ……..…………………………………………………………….…. burewalaensis (n.sp.)
18. Trifid sensillum absent; propodosomal shield not provided with pores; palpfemur not with 1 seta; seta h1 present; trochanter II not provided with 2 setae……………….…………………………………………….………………………..10
19. Main dorsal shield with few striations; eyes present; humeral shield dorsally visible; palpgenu provided with more than 1 seta; intercalary shield present; anogenital plate with incomplete striations…….……………………………………………….…. saeedii (n.sp.)
20. Main dorsal shield reticulated; eyes present; humeral shield dorsally absent; palpgenu provided with 1 seta; intercalary shield absent; anogenital plate without striations ………...…………………...……………………….………………..officinarumus (n.sp.)

Remarks: (1)

This new species closely related to Agistemus impavidus Chaudhri and can be separated from it due to following concerns.

1. Seta e2 longer than all other dorsal setae while in impavidus seta sci was the longest.
2. Seta sci equal in length with distance sci-sce in this new species while in Agistemus impavidus 1.30 times length of sci.
3. Mesal seta of genu I no longer than its segment length whereas in impavidus it was longer.
4. Ratio e/le=1.45 in it and in impavidus it was 1.60.
   Ratio h1/h2=1.45 in it and in impavidus it was 1.60.
   Note: e/le must be replaced with h1/h2
5. Three (3) pair of ps setae in this n.sp. while four (4) in A. impavidus.
6. Differences in number of setae on coxae, femora, genua, tibiae, tarsi in both species.
7. Pointed oval shape intercalary shield in this n.sp. while a regular one in A. impavidus.
8. Palp tarsalpeg having 2 setae where as in impavidus it is without seta.
9. Palp tarsalpeg without trifid sensillum in this species whereas in impavidus it was present.

I am thankful to Dr. Eddi Ueckermann, Fan and Salih Dogan for their assistance regarding stigmaeid literature and statistics. The authors are also grateful to Higher Education Commission (HEC) for their partial financial support for the preparation of this manuscript please.

The identification and description of a new predatory mite species (acari) as bio-control agent will play an immense role in integrated pest management program against different pest species from Pakistan.

The author declares no conflict of interest.

1. Stathakis T, Kapaxidi E, Papadoulis G. A new record and a new species of the genus Agistemus Summers (Acari: Stigmaeidae) from Greece. Zootaxa. 2014;3780:153‒170.
2. Hafez SM, Rasmy AH, Elsawi SA. Influence of prey species and stage on predatory efficiency and development of the stigmaeid mite Agistemus exsertus. Acarologia. 1983;24:281‒283.
3. Osman A, AM Zaki. Studies on the predation efficiency of Agistemus exsertus on the eriophyid mite Aculops lycopersici (Massee). Anz Schdlingskd Flanz Umweltschutz. 1986;59:135‒136.
4. Abou Awad BA, Elsawi SA. Biology and life table of the predacious mite, Agistemus exsertus Gonz. (Acari: Stigmaeidae). Anzeiger Fur Schadlingskunde. 1993;66(5):10‒103.
5. Momen FM. Effect of diet on the biology and life tables of the predacious mite Agistemus exsertus (Acari: Stigmaeidae). Acta-Phytopathologica-et-Entomologica Hungarica. 2001;36(1&2):173‒178.
6. Ferla NJ, Moraes GJ. Biologia de Agistemus floridanus Gonzalez (Acari, Stigmaeidae). Revista Brasileira de Zoologia. 2003;20(2):261‒264.
7. Summers FM. Several stigmaeid mites formerly included in Mediolata re-described in Zetzellia Oudemans and Agistemus, new genus. Proc Ent Soc Wash. 1960;62:233‒247.
8. Ehara S. Some mites of the families Phytoseiidae and Blattisociidae from Japan (Acari: Mesostigmata). J Fac Sci Hook Univ (ser 6) Zool. 1946;15:378‒394.
9. Gonzalez RH. A taxonomic study of the genera Mediolata, Zetzellia and Agistemus (Acari: Stigmaeidae ). Univ Calif Publ Ent. 1965;41:64.
10. Oudemans AC. Acarologische Aanteekeningen 108. Ent Ber Nederl. 1931;8:251‒263.
11. Baker EW, GW Wharton. An introduction to acarology. The Macmillan Co New York, USA; 1952.
12. Wood TG. A new species and records of Stigmaeidae (Acari: Prostigmata) from New Zealand. NZJ. 1981;8(3):369‒377.
13. Summers FM. Genera of the mite family Stigmaeidae Oudemans (Acari). Acarologia. 1966;8:230‒250.
14. Wood TG. A new species of Cheylostigmaeus willmann (Acari: Stigmaeidae ) from New Zealand. NZJ Sci. 1968;11:276‒279.
15. Chaudhri WM, S Akbar, A Rasool. Studies on the predatory leaf inhabiting mites of Pakistan. UAF Tech Bull. 1979;1:234.
16. Yousaf AA, MA Zaher, AM A El-Hafiez. Effect of prey on the biology of Amblyseius gossypi Elbadry and Agistemus exertus Gonzales (Acari: Phytoseiidae, Stigmaeidae ). Z Angew Entomol. 1982;93(5):453‒456.
17. Chaudhri WM, Akbar S. Studies on biosystematics and control of mites of field crops, vegetables and fruit plants in Pakistan. UAF Tech Bull. 1985;2:314.
18. Gupta SK. Handbook of plant mites of India. Calcutta, India: Sri Aurobindo Press; 1985. 520 p.
19. Yue B, CC Childers, AH Fouly. A comparison of selected plant pollens for rearing Euseius mesembrinus (Acari: Phytoseiidae). Int J Acarol. 1994;20(2):103‒108.
20. Siqin HU, X Chen, L Huang. A new species and a new record of the genus Agistemusfrom China. (Acari: Stigmaeidae ). Syst Appl Acarol Sco. 1997;1:1‒4.
21. Fan, QH, X Liu. New species of Ledermulleriopsis Willmann and Pseudostigmaeus Wood from China (Acari: Prostigmata: Stigmaeidae ). Syst Appl Acarlogy. 1999;4(1):153‒158.
22. Fan, QH, DE, et al. A review of the genus Ledermuelleriopsis willmann (Acari: Prostigmata: Stigmacidae). Invert Syst. 2003;17(4):551‒574.
23. Fan, QH, DE Walter. Mediostigmaeus genn (Acari: Stigmaeidae) with description of a new species from USA. Zootaxa. 2005;1036:21‒29.
24. Devis RM, JG Demoraes, MR Bellini. Effect of air humidity on the egg viability of predatory mites (Acari: Phytoseiidae, Stigmaediae) common on rubber trees in Brazil. Exp Appl Acarol. 2006;38(1):25‒32.
25. Faraji, Ueckarmann. A new speices of Mediolata Canestrixi from Spain (Acari: Stigmaeidae), redescription of M. chanti and a key to the known species of Mediolata. Zookaxa. 2006;1151:27‒39.
26. Meyer, M K P. Some Stigmaeid mites from South Africa (Acari: Trombidiformes). Acarologia. 1969;11(2):207‒217.
27. Meyer MKP, Ryke PAJ. Mites of the superfamily Raphignathoide (Acari: Prostigmata) associated with South African plants. Ann Mag Nat Hist. 1959;13:209‒234.
28. Wood TG. New Zealand mites of the family Stigmaeidae (Acari: Prostigmata). Trans Roy Soc NZ Zool. 1967;9(9):93‒139.
29. Wood TG. Stigmaeidae (Acari: Prostigmata) from Campbell Island. Acarologia. 1970;12:677‒683.
30. Chaudhri, Wali M. Taxonomic studies of the mites belonging to the families Tenuipalpidae, Tetranychidae, Tuckerellidae, Caligonellidae, Stigmaeidae and Phytoseiidae. Tech Bull. 1974;1:250.
31. Koch, CL, Herrich-Schäffer, Gottlieb August Wilhelm. Deutschlands Crustaceen, Myriapoden und Arachniden. Ein Beitrag zur Deutschen Fauna. Regensburg, F Pustet, German; 1836.
32. Tseng, YH. Mites of the family Stigmaeidae of Taiwan with key to genera of the world (Acari: Prostigmata). Phytopathologist and Entomologist NTU. 1982;9:1‒52.
33. Grandjean F. Observations sur les acariens de la famille des Stigmaeidae. Arch Sci Phys Nat. 1944;26:103‒131.