Research Article |
Corresponding author: Wayne Knee ( whknee@gmail.com ) Academic editor: Vladimir Pesic
© 2017 Wayne Knee.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Knee W (2017) A new Paraleius species (Acari, Oribatida, Scheloribatidae) associated with bark beetles (Curculionidae, Scolytinae) in Canada. ZooKeys 667: 51-65. https://doi.org/10.3897/zookeys.667.12104
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Bark beetles (Scolytinae) are hosts to a broad diversity of mites (Acari), including several genera of Oribatida (Sarcoptiformes). Of these, Paraleius (Scheloribatidae) species are the most frequently collected oribatid mites associated with bark beetles. A new species was discovered while surveying the acarofauna of bark beetles in Eastern Canada and is described as Paraleius leahae sp. n. (Oribatida, Scheloribatidae). This species was collected from two host beetle species, Hylastes porculus Erickson and Dendroctonus valens LeConte, in Ontario, New Brunswick and Nova Scotia. The genus Paraleius is rediagnosed, Metaleius is considered a synonym of Paraleius, and the proposed synonymy of Paraleius with Siculobata is rejected. The three known species are Paraleius leontonycha (Berlese), P. leahae sp. n., and P. strenzkei (Travé), comb. n. The barcode region of cytochrome oxidase subunit I (COI) was amplified from P. leahae sp. n.
Mite, Acari , phoresy, COI, forest entomology, ecology
A broad assemblage of wood-burrowing beetles (Cerambycidae, Buprestidae, Scolytinae), and associated mites, nematodes, and fungi reside under the bark of dead, dying or living trees. Bark beetles (Curculionidae, Scolytinae) are a diverse group of wood-borers that feed and mate in the cambium or xylem of numerous tree species worldwide (
Oribatid mites (Acari, Oribatida) dwell primarily in soil or forest litter, though many are found in arboreal habitats and a few occur in aquatic systems (
Bark beetle specimens collected with Lindgren funnel traps in eastern Ontario by
Oribatid collections at the Canadian National Collection of Insects, Arachnids, and Nematodes (
Slide-mounted specimens were examined using a Leica DM2500 compound microscope and Leica ICC550 HD camera, with differential interference contrast illumination (DIC). Initial drawings of mites were made with pencil on paper using a camera lucida. These were later merged in Adobe Photoshop CS5 and redrawn in Adobe Illustrator CS5 using an Intuos 3 Graphics Tablet from WACOM Co., Ltd. (Saitama, Japan).
Morphological terminology used in this study follows that developed by F. Grandjean (see
Genomic DNA was extracted from whole specimens for 24 hours using a DNeasy Tissue kit (Qiagen, Inc., Santa Clara, California, United States of America). Following extraction, mites were removed from the extraction buffer, vouchers were-slide mounted, and genomic DNA was purified following the DNeasy Tissue kit protocol. PCR amplifications were performed in a total volume of 25 µl, with 14.7 µl ddH2O, 2.5 µl 10× ExTaq buffer, 0.65 µl 25 mM MgCl2, 1.0 µl of each 10 µM primer, 2.0 µl 10 mM dNTPs, 0.15 µl ExTaq DNA polymerase, and 3 µl genomic DNA template. Primer pairs PHF1 (5’–CWACAAAYCAYAAAGATATTGG–3’) and PHR1 (5’–TAHACYTCHGGRTGVCCRAAAAAYCA–3’) were used to amplify a 641 bp fragment of the 5’–end of COI. PCR amplification was performed on an Eppendorf ep Gradient S Mastercycler (Eppendorf AG, Hamburg, Germany), using the following protocol: initial denaturation cycle at 94 °C for 3 min, followed by 45 cycles of 94 °C for 45 s, primer annealing at 40 °C for 45 s, 72 °C for 1 min, and a final extension at 72 °C for 5 min. Amplified products and negative controls were visualized on 1% agarose electrophoresis gels, and purified using pre-cast E-Gel CloneWell 0.8% SYBR Safe agarose gels (Invitrogen, Carlsbad, California, United States of America). Sequencing reactions followed the protocol of
Paraleius (=Oribella) leontonycha (Berlese, 1910)
Rostrum extended medially, forming narrow point; anterior border of notogaster convex; prodorsal setae long, thickened, attenuate, barbed; bothridium inserted dorsolaterally, close to lamella; bothridial seta capitate or fusiform; bothridium covered with numerous spicules; prolamella present; sublamella and translamella absent; pteromorphs absent; exobothridial seta (ex) medium sized and barbed; humeral porose organ (Ah) expressed as saccule; four pairs of saccules on notogaster; Ten pairs of medium sized notogastral setae; shallow sternal groove on ventral surface; solenidia of tibiae III and IV microcephalic (rounded vesicle) or not; eupathidia p of tarsus I smooth, seta p of tarsus II–IV with small bristles along one side; seta s of tarsus I with large barbs along ventral side, not eupathidial; leg pretarsi monodactylous or hetero-tridactylous with large curved median claw, lateral claws (if present) long and thin, resembling setae.
While
In his checklist of the world oribatid mite fauna,
Type material. Holotype: adult female (vial CNC649357) on Hylastes porculus (female) collected in Westfield, Nova Scotia, Canada (44.40316, -64.97473), 28.v.2009, coll: W. Knee.
Paratypes (20): one female (vial CNC649359) with the same collection information as the holotype; female (vial CNC649361) on H. porculus (male), St. Stephen, Highway 1, New Brunswick (45.22321, -67.15371), 15.vi.2009, coll: W. Knee; female (vial CNC649362) on H. porculus (male), Bayside, Route 127, New Brunswick (45.20539, -67.14034), 15.vi.2009, coll: W. Knee; male (vial CNC649363) on H. porculus (female), Turner and Turner Mill, West Northfield, Nova Scotia, 1.vi.2009, coll: W. Knee; two females and two males (slides CNC649365–649368) on H. porculus, Algonquin Provincial Park (PP), Ontario (45.902, -77.605), 17.vi.2008, coll: W. Knee; one female and three males (slides CNC649371–649374) on H. porculus, Algonquin PP, Ontario (45.902, -77.605), 3.vi.2008, coll: W. Knee; two females (slides CNC649375, CNC649376) on Dendroctonus valens, Algonquin PP, Ontario (45.895, -78.071), 3.vi.2008, coll: W. Knee; three females and three males (slides CNC649378–649383) on D. valens, Algonquin PP, Ontario (45.895, -78.071), 28.v.2008, coll: W. Knee.
67 slide mounted specimens from D. valens, and 22 from H. porculus collected in Algonquin PP, Ontario (45.895, -78.071), 2008–2009, coll: W. Knee; one slide mounted specimen from D. valens, and 70 from H. porculus collected in Algonquin PP, Ontario (45.902, -77.605), 2008–2009, coll: W. Knee.
As for Paraleius (see above). Bothridial seta long and fusiform, covered with numerous spicules; carina kf present; tarsi monodactylous with prominent sickle shaped strongly hooked claw; solenidia of tibiae III and IV not microcephalic. Immatures unknown.
Measurements. Total length female (n = 4) 453 (432–464), male (n = 7) 430 (423–440). Total width female (n = 4) 277 (255–296), male (n = 7) 274 (258–295).
Integument. Body cuticle red-brown. Notogastral surface and venter appear smooth, but with fine granulate structure at higher magnification (100x). Small microtubercles on epimeral surface (Fig.
Prodorsum (Figs
Lateral aspect of podosoma (Figs
Notogaster (Figs
Venter (Figs
Gnathosoma (Fig.
Legs (Fig.
Leg setation and solenidia of adult Paraleius leahae sp. n., single prime (’) indicates setae on anterior and double prime (”) setae on posterior, seta in parenthesis indicates the presence of both setae.
Leg | Trochanter | Femur | Genu | Tibia | Tarsus |
---|---|---|---|---|---|
I | v’ | d, (l), v’, bv” | (l), v’, σ | (l), (v), φ1, φ2 | (ft), pl’, (tc), (it), (p), (u), (a), s, (pv), (v), ε, ω1, ω2 |
II | v’ | d, (l), v”, bv” | (l), σ | (l), (v), φ | (ft), (tc), (it), (p), (u), (a), s, (pv), ω1, ω2 |
III | d, l’ | d, l’, ev’ | l’, σ | l’, (v), φ | (ft), (tc), (it), (p), (u), (a), s, (pv) |
IV | v’ | d, ev’ | d, l’ | l’, (v), φ | ft”, (tc), (p), (u), (a), s, (pv) |
Gender differences. No sexual dimorphism exists in external morphology, except for males being slightly smaller than females, their genital plates being slightly smaller proportionally than in females, and in the typical genitalic differences.
Genetics. There are no other sequences of Paraleius or Metaleius on GenBank; however, GenBank blast searches of the COI sequence (KY402259) of P. leahae sp. n. generally matches that of other poronotic brachypyline oribatid mites. Further analysis was not performed.
This species is named after my wife and tireless supporter Leah Harper.
Paraleius leahae sp. n. is most similar to P. leontonycha (
Paraleius leahae sp. n. differs from P. (=Metaleius) strenzkei in having a long fusiform bothridial seta; monodactylous tarsi, medial claw large and strongly hooked; carina kf present; total length (432–464) of P. leahae females greater than P. strenzkei (310–360) (
According to
Paraleius leontonycha and P. leahae are quite similar morphologically, and it is possible that the latter has been misidentified as the former in the past. These two species are also ecologically similar in being corticolous and phoretic on bark beetles. The feeding biology of P. leahae and P. leontonycha is poorly understood, but fungal hyphae have been observed in the gut of slide mounted specimens of both species.
Paraleius leontonycha is the most commonly collected and widely distributed oribatid phoretic on bark beetles, however this species occurs infrequently and in low abundance (
Typically the association between oribatid mites and their scolytine hosts is considered to be passive and with low host specificity (
1 | Tarsi monodactylous, central claw large sickle shaped and strongly hooked, hair-like lateral claws absent. Carina kf present. Long fusiform bothridial seta | Paraleius leahae sp. n. |
– | Tarsi hetero-tridactylous, large curved central claw, lateral claws hair-like. Carina kf absent. Capitate bothridial seta | 2 |
2 | Central claw sickle shaped and strongly hooked. Solenidia of tibiae III and IV microcephalic. Total length approximately 435–480 µm | Paraleius leontonycha (Berlese, 1910) |
– | Central claw evenly curved, c-shaped. Solenidia of tibiae III and IV not microcephalic. Total length approximately 310–360 µm | Paraleius strenzkei (Travé, 1960) |
I am grateful to V. Behan-Pelletier and R.A. Norton for their advice and assistance throughout this project. I also thank T. Hartzenberg, H.W. Knee, and R. Shewchuk for their help in the field and the lab, as well as the private land owners who permitted sampling on their property. I thank S.G. Ermilov for his thoughtful review of the manuscript. This research was conducted with a permit to collect in Provincial Parks issued by Ontario Parks and coordinated by B. Steinberg.