INTRODUCTION

Phoresy is unique behaviors of wingless arthropod dispersal by attaching winged arthropods. Many species of mites take advantage of long distance dispersal from unfavorable environments utilizing the winged insects such as beetles, flies and even dragonflies. These phoretic mites often show mutualistic interaction with the phoretic hosts or parasitic to the host. In dung beetle and mesostigmatid mites system, beetles serve as a carrier vehicle of predatory mesostigmatid mites while those mites secure food and nest resources for beetles by attacking the eggs and larvae of flies which are one most important competitors of dung. However, in many of dipteran-mite interactions, antagonistic interaction prevails. Arctoseius cetratus (Ascidae) is known to phoretic on the mushroom sciarid fly Lycoriella auripila (Diptera: Sciaridae) (Binns 1972, 1974; Dmoch 1995) and predatory of various dipteran eggs and early larvae resulted in 85% egg hatch failure of L. auripila.

The Ascidae is an important predator group that inhabits various microhabitats such as leaf litter, rotten wood, feeding sites of insects, anthills, and bird’s nests. They are known to be useful biological indicator of microhabitat and potential biological control agents of various soil dwelling arthropod pests (Karg and Freier 1995; Ruf 2000). In Korea, 10 genus and 25 species are reported in the family Ascidae with taxa of Antennoseius (two species), Asca (6), Blattisocius (1), Cheiroseius (3), Euryparasitus (3), Lasioseius (5), Leioseius (2), Protolaelaps (1), Protogamasellus (1), Zerconopsis (1) (NLSK 2013). In the World, there are 39 genus and 558 species in the family Ascidae with dominant taxa of Lasioseius (142), Cheiroseius (76), Asca (61), Protolaelaps (54), Antennoseius (32) (Hallan 2008). During the study of sciard fly control in mushroom culture, mites attached on the fly was further identified as Arctoseius cetratusSellnick 1940, which is new record from Korea. Here we detailed the first description of Arctoseius cetratus in Korea, and provide the identification key within the subfamily Arctoseiinae with some ecological notes.

Materials and Methods

Sciarid flies, Lycoriella mali were collected from the bed of mushroom (Agaricus bisporus) cultures in Yangmok-myeon, Chilgok-gun, Gyeongsangbuk-do (36°02′03.89″N, 128° 23′57.47″E) in Jun, 2014. The mites attached on the ventral part of flies were recovered. All specimens were preserved in 70% ethanol and mounted on slide glass in PVA mounting medium (polyvinyl alcohol-lactic acid) (Downs 1943; BioQuip, Rancho Dominiquez, CA, USA). Species identification was based on Gwiazdowicz (2007) and Halliday et al. (1998). The collected original samples were deposited in the Mite Collection of Andong National University, Insect ecology lab.

Key to subfamilies Arctoseiinae Evans, 1963

Dorsal shield of adults entire, with or without lateral incisions; opisthonotal region usually with maximum of four pairs of lateral S setae, S2 usually not added in change from larva to protonymph. Marginal (r-R) series of setae lacking r6 in podonotal region and often R6 posteriorly; marginal R setae on lateral soft cuticle on female, but variably on dorsal shield margin on male. Submarginal (UR) setae absent. Female sternal shield with third pair of lyrifissures on its posterior margin; fourth pair of sternal setae on soft cuticle. Sternal setae st5 usually on soft cuticle flanking female epigynal shield. Male sternitigenital shield free from, but sometimes abutting ventrianal shield, and often not fully integrated with endopodal strips alongside coxae III-IV. Maximum number of setae on genua I-II-III-IV, respectively, 12-10-8-7; on tibiae, 12-9-7-7; in change from protonymph to deutonymph, seta pd-3 not added to genu and tibia I, pl-2 not added to genu and tibia II, and al-2 not added to genua and tibiae IIIIV. Plesiomorphic attributes of the Arctoseiinae include the following: Gnathotectum basically bi- or tri-ramous, each process simple or denticulate; cheli- ceral movable digit bidentate in female, unidentate in male, without pointed process on mid-ventral surface, and with fringed arthrodial envelope basally; cheliceral fixed digit with small, setiform pilus dentilis, with usually few teeth restricted to apical half of masticatory surface, and without hyaline serrate rim near base on paraxial surface. Tarsus I usually with a conspicuously lanceolate-tipped seta dorsodistally. In change from protonymph to deutonymph, seta ad-3 added to genua I-II and tibia I, ad-2 added to tibia II, and al-2 added to tibia II .... .............................................................................. Arctoseiinae

Key to genera

1. Two shields on body dorsum ........................................ 2

- One shield on body dorsum .......................................... 5

2. Leg Ⅰwith claws ............................................................. 3

2. Leg Ⅰwithout claws ..................................... Antennoseius

3. None of the opisthonotal setae on tubercles, but directly on shield ........................................................................ 4

4. Line extending across podonotal shield in region of z6 setae and cross opisthonotal shield in region of J1 setae.... ............................................................... Protogamasellus

5. Dorsum withous spatulate setae .................................... 6

6. Schizodorsal shield on body dorsum ............................ 7

7. Ventri-anal shield on body venter .................... Leioseius

- Anal shield on body venter ............................ Arctoseius

Family Ascidae

Genus Arctoseius Thor, 1930

Synonyms: TristomusHughes, 1948; ArctoseiulusWillmann, 1949, ArctotarseiusWillmann, 1949; ArctoseiopsisEvans, 1954.

Morphology

Dorsal: Dorsal idiosoma with schizodorsal shield, with well-defined medial incisions. Shield with 31 to 33 pairs of setae, 14 of them in the posterior region. Marginal setae on lateral integument. Dorsal setae smooth, simple none paddle- shaped. Ornamentation usually poorly defined and most frequently alveolate, areolate or colliculate.

Ventral: Sternal shield with three pairs of setae, seven denticulate rows. Epistome bi-or tri-ramous, margins smooth but with tips of processes denticulate in some species. Movable digit of chelicera usually bi-dentate bue dentition of fixed digit variable, three well-separated teeth to row of small closely-set teeth. Palp without macroseta on tarsus.Fig .1

Arctoseius cetratus (Sellnick, 1940)

Synonyms: Arctoseius cetratus (Sellnick)

Lasioseius cetratusSellnick, 1940: 99.

Arctoseius bispinatus Weis-Fogh, 1948: 255. Synonymy by Evans (1955).

Arctoseius halophilusWillmann, 1949: 354. Synonymy by Karg (1971).

Arctoseius erlangensisSellnick, 1958: 23. Validation of a manuscript name from unpublished dissertation of a name from unpublished dissertation of Hirschmann (1951).

Synonymy by Karg (1971).

Iphidozercon erlangensis.-Hirschmann, 1962: 30. Synonymy by Karg (1971).

Arctoseius cetratus.-Evans, 1958: 186; Karg, 1993: 264; Walter and Lidquist, 1995: 430.

Diagnosis: Dorsal shield with lateral incisions and 31 pairs of setae, posterior dorsal-shield setae short, not reaching insertions of following setae; posterior half of dorsal shield with longitudinal garland of puncta between J and Z setae; peritremes extending anteriorly to mid-level of coxae II; epistome 2-tined; fixed chela with a row of 6-8 teeth; male leg II with tarsal seta al-2 modified, swollen basally and trichoid distally.Fig .2

Habits and world distribution: North America (Chant 1963); Europe (Bregetova 1977; Karg 1993; Salmane and Heldt 2001; Kaluz and Fenda 2005); Western Europe (Bregetova 1977); Russia: soil (Petrova 1982; Makarova 2000); Western Siberia (Davydova and Nikolsky 1986); Middle Ural (Russia): fallow land (Khomjakov 1988); Australia: dung-baited, pitfall trap, New South Wales: cow dung, Victoria: compost (Halliday et al. 1998); Poland: nest of Greater spotted Eagle (Aquila clanga) (Gwiazdowicz et al. 2000), soil (Seniczak et al. 2000), rotten wood, leaf litter and other microhabitats (Gwiazdowicz and Klemt 2004), sod, stuffing from nests of (Larus ridibundas) (Gwiazdowicz and Kmita 2004), litter, rot wood, moss (Gwiazdowicz and Matysiak 2004), litter, rotting wood, sod, meadow, bark beetles galleries (Gwiazdowicz 2004), Nests of formicidae (Formica polyctena), (Lasius niger) (Gwiazdowicz 2008a), associated with Scolytidae (Gwiazdowicz 2008b), soil (Gabrys et al. 2008); Sakhalin and Kuril Islands: manure (Marchenko and Mapyehko 2002); Slovakia: various habitats (Kaluz and Fenda 2005), nests of mound-building mouse (Musspicilegus) (Masan and Stanko 2005), birds’ nests (Fenda and Schniererova 2010); Central Argentina: Soil (Bedano and Ruf 2007); Saudi Arabia: fruit and timber trees (Al-Atawi 2011); Austria: roots and soil of plants (Wissuwa et al. 2012); Iran: Soil (Montazeri et al. 2011; Nemati 2011, 2012a).

Food: Gamsid mites in Mesostigmata in general and mites of the genus Arctoseius specially are predatory, feeding on the immature forms of Astigmata, Oribatida, Collembola and Nematoda, as well as the eggs and larvae of Diptera (Weis- Fogh 1947; Kargi 1961; Hussey 1968; Binns 1972, 1973 (II), 1974) for biological control of sciard pests in mushroom production, species in genus of Hypoaspis such as H. aculeifer and H. miles are often preferred (Jess and Bingham 2004) but also, Arctoseius has a great potential (Binns 1974; Dmoch 1995; Jess and Bingham 2004).

Dispersal: In the soil habitats, ambulatory movement is the main dispersal mechanism of Arctoseius cetratus in relatively shorter distance, while it exhibits phoretic dispersal on sciarid flies as carrier mostly in mushroom farms (Binns 1972, 1974; Rudzinska 1998).

Deposition: Andong National University, Insect Ecology Lab.

Identifier: Eunsun Keum.