Summaries of taxonomic knowledge are provided for all acarine groups in Canada, accompanied by references to relevant publications, changes in classification at the family level since 1979, and notes on biology relevant to estimating their diversity. Nearly 3000 described species from 269 families are recorded in the country, representing a 56% increase from the 1917 species reported by Lindquist et al. (1979). An additional 42 families are known from Canada only from material identified to family- or genus-level. Of the total 311 families known in Canada, 69 are newly recorded since 1979, excluding apparent new records due solely to classification changes. This substantial progress is most evident in Oribatida and Hydrachnidia, for which many regional checklists and family-level revisions have been published. Except for recent taxonomic leaps in a few other groups, particularly of symbiotic mites (Astigmata: feather mites; Mesostigmata: Rhinonyssidae), knowledge remains limited for most other taxa, for which most species records are unpublished and may require verification. Taxonomic revisions are greatly needed for a large majority of families in Canada. Based in part on species recorded in adjacent areas of the USA and on hosts known to be present here, we conservatively estimate that nearly 10,000 species of mites occur in Canada, but the actual number could be 15,000 or more. This means that at least 70% of Canada’s mite fauna is yet unrecorded. Much work also remains to match existing molecular data with species names, as less than 10% of the ~7500 Barcode Index Numbers for Canadian mites in the Barcode of Life Database are associated with named species. Understudied hosts and terrestrial and aquatic habitats require investigation across Canada to uncover new species and to clarify geographic and ecological distributions of known species.

The Acari (mites) is currently interpreted to consist of two superorders. In contrast to the relatively rich history of the mite superorder Acariformes, fossils of the Parasitiformes are extremely rare. This is especially true of the most diverse order, Mesostigmata, with only nine families recorded, including four named species, having been described so far. As part of a wider effort to clarify the diversity of Baltic amber Mesostigmata the historically oldest fossil, Sejus bdelloides Koch and Berendt, 1854, is re-examined. While clearly a mite, it is not a mesostigmatan, but a member of the Prostigmata (Acariformes), referable to the Anystina. Thus of the three main mesostigmatan lineages currently recognised both Sejida and Trigynaspida lack a fossil record. Monogynaspida can be traced with confidence back to the Eocene (ca. 44 - 49 Ma).

Three experiments were set up to determine whether two of the pesticides that are widely used in the sugarcane industry are detrimental to soil microarthropods. A particular focus was the effect of the pesticides on mesostigmatid mites, as they are nematophagous and help regulate populations of the nematode pests that cause damage to sugarcane. An experiment with liquid formulations of imidacloprid and bifenthrin was established at one site, while the effects of a controlled release formulation of imidacloprid were examined at two other sites. In the experiments where sugarcane was planted, the pesticides were applied to the planting furrow in a band 20 cm wide that was located 2-4 cm above recently-planted setts. Microarthropods were extracted from soil samples collected 9 weeks after the liquid formulations were applied and about 15 months after the experiments with a controlled release formulation of imidacloprid were established. In all cases, the number and diversity of the microarthropods recovered from the samples was similar in pesticide-treated and untreated plots. Also, populations of mesostigmatid mites and their nematode prey were not affected by either bifenthrin or imidacloprid. These results indicate that the non-target effects of imidacloprid and bifenthrin on soil microarthropods are negligible, possibly because the pesticides are applied in a band in the centre of the row and much of the profile (vertically and horizontally) remains as an untreated reservoir that can be used by the organisms as a safe refuge.

Soil biological health is a topic of great interest to sugarcane growers, although there is confusion as to what constitutes soil health. Many growers and consultants are unaware that beneficial organisms, rather than pathogens and pests, dominate the biological community in a healthy soil. Considering the vast diversity of soil organisms and their complex interactions, it is unsurprising that there is limited knowledge about how farming practices precisely impact on soil biological health, and how biological health can be achieved. The former Sugar Yield Decline Joint Venture (SYDJV) and subsequent activities have demonstrated that soil biological health represents a significant production constraint. The modern farming system (MFS), with controlled traffic, permanent beds, minimum tillage, legume break crops and crop residue retention, aims to overcome soil constraints, including soil biological health, by minimising problems arising from soil compaction, continuous monoculture and low levels of soil organic matter. In this paper we discuss key organisms that inhabit soils under sugarcane production and how soil biology responds to management practices. We highlight biological indicators of soil health, and their usefulness to growers for quantifying soil responses to changed farming practices. We outline research needs to advance the industry's ability to manipulate soil biological health.

Protogamasellus mica was extracted from a sugarcane field in Australia and cultured on bacterial-feeding nematodes. Studies with various nematodes in laboratory arenas showed that one mite and its progeny reduced nematode numbers by between 26 and 50 nematodes/day. A bacterivore (Mesorhabditis sp.), a fungivore (Aphelenchus avenae), and two plant parasites (root-knot nematode, Meloidogyne javanica and root-lesion nematode, Pratylenchus zeae) were all reduced at much the same rate despite the fact that the nematodes are quite different in size and motility and belong to different trophic groups. When sugarcane was grown in the greenhouse for 8 wk, stunt nematode (Tylenchorhynchus annulatus), a plant parasite that feeds ectoparasitically on roots, was almost eliminated from pots inoculated with the mite, and numbers of microbivores and root-lesion nematode were markedly reduced. Huge reductions in nematode populations were also observed when mites were added to microcosms containing small quantities of defaunated soil. These results show that P. mica multiplies rapidly when nematodes are available as a food source and has the capacity to play a role in regulating populations of both plant-parasitic and free-living nematodes. Future research should focus on understanding the crop and soil management practices required to enable this mite and other predatory species to thrive.

Fossil mesostigmatid mites (Acari: Parasitiformes: Mesostigmata) are extremely rare, and specimens from only nine families, including four named species, have been described so far. A new record ofMyrmozerconsp. described here from Eocene (ca44–49 Myr) Baltic amber represents the first—and so far only—fossil example of the derived, extant family Laelapidae. Significantly, modern species of this genus are habitually myrmecophilous and the fossil mite described here is preserved attached to the head of the dolichoderine antCtenobethylus goepperti(Mayr, 1868). It thus offers the oldest unequivocal evidence for an ecological association between mesostigmatid mites and social insects in the order Hymenoptera.

Volume 32(2) Winter 2013 Return to front page The Status of Systematic Knowledge of the Acari of Canada: Tickin’ Away with Some Mitey Progress Lisa Lumley1, Frédéric Beaulieu2, Valerie Behan-Pelletier2, Wayne Knee2, Evert E. Lindquist2, Michelle Mark1, Heather Proctor3, and David Walter4 1Royal Alberta Museum, Edmonton, Alberta, Canada; 2Agriculture and Agri-Food Canada, Canadian National Collection of Insects, Arachnids and Nematodes, Ottawa, Ontario, Canada; 3University of Alberta, Edmonton, Alberta, Canada; 4University of the Sunshine Coast, Queensland, Australia

Species in the oribatid mite genus Tectoribates are primarily Palaearctic and Neotropical, with scattered, unidentified records from North America. Herein, we describe 3 new Tectoribates species from dry forest and prairie habitats in North America: T. alcecampestris sp. nov., from Alberta, T. borealis sp. nov., from southern Alberta and Ontario, both on the basis of adults and nymphs, and T. campestris sp. nov., from dry grassland habitats in Ontario and Kansas, on the basis of adults. We provide a revised and expanded diagnosis for adults of Tectoribates. We assess relationships of Tectoribates, using characters of adults and newly discovered apheredermous, plicate immatures. We include observations on Pseudotectoribates which is closely related to Tectoribates. The closest relatives of these genera are hypothesised to be among the Tegoribatidae (Achipterioidea) rather than among the Achipteriidae (Achipterioidea), Oribatellidae (Oribatelloidea), or Ceratozetoidea, as suggested in previous classifications. Finally, we give a key to adults of the world fauna of Tectoribates.

The oribatid mite genus Oribatella (Oribatellidae) includes 18 species known previously from North America. Herein, we describe 11 new Oribatella species from montane, subarctic, forest and prairie habitats in western North America: O. abmi sp. nov., O. banksi sp. nov., O. ewingi sp. nov., O. heatherae sp. nov., O. manningensis sp. nov., O. maryae sp. nov., O. oregonensis sp. nov., O. parallelus sp. nov., O. pawnee sp. nov., O. sintranslamella and O. yukonensis sp. nov. Descriptions of two species (O. heatherae and O. pawnee) include some developmental instars. That of O. yukonensis includes all instars; nymphs retain dorsocentral setae dm and dp, but the setal morphology changes between larva and nymphs. These immatures bear sclerotized areas on the hysterosoma. Adults of Oribatella oregonensis show distinct sexual dimorphism, with three notogastral setae arising from fused porose areas in the male. We provide new distribution records for Oribatella species previously known from North America, including O. arctica Thor, 1930, O. canadensis Behan- Pelletier and Eamer, 2010, O. jacoti Behan- Pelletier, 2011 and O. reticulatoides Hammer, 1955, and remark on O. anomola Grabowski, 1970. We clarify description of the octotaxic system and the interlamellar region in species of Oribatella and discuss variability in hysterosomal sclerotization and setation in immatures. Finally, we give a key to adults of the 29 species of Oribatella now known from North America.

Currently, six genera are known in the family Camerobiidae (Acari: Prostigmata). Herein we propose a new genus, Acamerobia, based on a new species, Acamerobia inflatus, from bark of Jacaranda mimosifolia in Brisbane, Australia, and redefine the family and provide a key to genera. We also give comments on the idiosomal chaetotaxy for the family.

We identified species of mites phoretically associated with mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), collected from bolts of lodgepole pine, Pinus contorta Douglas ex Louden (Pinaceae), and pheromone-baited traps in northwestern Alberta, Canada. Mite load and species composition were compared between beetle sexes and with beetle emergence time and estimated body size. The vast majority of mites associated with D. ponderosae in Alberta belonged to three species: Proctolaelaps subcorticalis Lindquist (Acari: Mesostigmata: Melicharidae), Histiogaster arborsignis Woodring (Acari: Astigmatina: Acaridae), and Tarsonemus ips Lindquist (Acari: Prostigmata: Tarsonemidae). There was no difference in mite loads on male and female beetles recovered from bolts in the laboratory and those from pheromone-baited traps in the field. More mites were found on larger beetles in the laboratory, but only T ips showed this pattern on field-trapped beetles. There was no relationship between total mite load or load by mite species and beetle emergence time in the laboratory, but total mite load on field-trapped beetles decreased over the collecting season (10 June 3 September 2009) at five collection locations (Grovedale, Blueberry Mountain, Hythe, Evergreen Park, and Glenleslie). This study is the first to document the assemblage of phoretic mites on D. ponderosae in Alberta and will help to direct future research on their interactions.

ABSTRACTSuspended soils in forest canopies are thought to harbor a substantial fraction of canopy biomass and many arboreal specialists, but do forest floor generalist predators with high vagility also use this habitat? We tested the hypothesis of no difference between forest floor and suspended‐soil predatory mite faunas (Acari: Mesostigmata) in an Australian rain forest. Our results show that instead of being habitat generalists, many predatory mites partition soil into two main strata: soil suspended aboveground irrespective of height (0.5–20 m) and soil on the ground. Of 53 species of Mesostigmata in suspended soil, 53 percent (28 species) were absent from or rarely found on the ground. This increased to 60 percent (15/25 species) if only common species are considered. Among these 15 ‘suspended‐soil specialists’, all but the three least abundant were found throughout the arboreal strata. Moreover, ten species also occurred in litter accumulated on the surface of decaying logs or boulders close to the forest floor. Thus, although the arboreal predatory mite fauna is distinct from that on the forest floor, it is not restricted to the high canopy: even slightly elevated substrate appears acceptable as habitat for these suspended‐soil specialists. Our data suggest that a substantial portion of a rain forest's soil and litter fauna is held above the forest floor.

We propose a new species of oribatid mite, Unduloribates dianae sp. nov., based on material collected from a variety of boreal habitats in the Canadian Provinces Newfoundland, Nova Scotia, Québec, Alberta and British Columbia, and in New York State in the USA. This is the first species in this genus from the Nearctic. Description is based on adults and all immature stages. We present an expanded generic diagnosis and a key to world species of Unduloribates, and argue for the retention of Unduloribatidae as a monogeneric family in Phenopelopoidea.

The mite genus Antennoseius is composed of free-living species in soil and litter, as well as species that are phoretic on carabid beetles as adult females. Among approximately 60 described Antennoseius species, one North American species, A. janus, was found in laboratory cultures to have two female morphs: one granular, free-living morph, and one smooth, putatively phoretic morph. We here describe the adult females of A. perseus n. sp. and A. pyrophilus n. sp. collected from under the elytra of carabid beetles (Sericoda quadripunctata and S. bembidioides) associated with recently burned forests in Alberta, Canada. We also describe the female and male of a distinct, granular, non-phoretic morph of A. perseus, obtained from soil and by rearing the offspring of phoretic females. A key to the females of Antennoseius species having an ambulacrum on leg I (i.e. subgenus Vitzthumia) is provided.

Eight previously unreported domatia-inhabiting mites are reported from Coffea arabica L. and C. eugenioides S. Moore (Rubiaceae) accessions planted in Costa Rica. One of these, an Asca sp., was found to be carrying fungal spores on its cuticle. A review of the literature on mites in coffee domatia is presented.

We propose a new genus of licneremaeoid oribatid mite, Phylleremus, based on two new species collected from leaves of woody dicots in Queensland, New South Wales, Victoria and Tasmania, Australia. Description of the type species, Phylleremus leei n. sp., is based on adults and all active immature stages; that of Phylleremus hunti n. sp. is based on adults and tritonymphs. Phylleremus adults have the notogastral octotaxic system of dermal glands developed either as 1 or 4 pairs of saccules, and nymphs are bideficient and plicate. We discuss the characteristics and relationships of this genus to others in Licneremaeoidea and argue for an affiliation with Adhaesozetidae.

Fusacarus australis sp. n. (Acari: Glycyphagidae) is described from specimens from tree holes and rainforest litter in Lamington National Park, Queensland. This is the first record of Fusacarus Michael from the Southern Hemisphere, and the first Australian native species of Glycyphagidae. A key to the world fauna of Fusacarus is provided.

Predatory mites (Acari: Mesostigmata) on tree trunks without significant epiphytic growth in a subtropical rainforest in Eastern Australia were assessed for habitat specificity (i.e. whether they are tree trunk specialists or occupying other habitats) and the influence of host tree and bark structure on their abundance, species richness and species composition. The trunks of nine tree species from eight plant families representing smooth, intermediate and rough bark textures were sampled using a knockdown insecticide spray. In total, 12 species or morphospecies of Mesostigmata (excluding Uropodina sensu stricto) were collected, most of which are undescribed. Comparison with collections from other habitats indicates that epicorticolous Mesostigmata are mainly represented by suspended soil dwellers (six species), secondarily by generalists (four species) and a bark specialist (one species). A typical ground-dwelling species was also found but was represented only by a single individual. In terms of abundance, 50.5% of individuals were suspended soil dwellers, 40.7% bark specialists, and 8.3% generalists. Host species and bark roughness had no significant effect on abundance or species richness. Furthermore, there was no clear effect on species composition. The distribution of the most frequently encountered species suggests that most mesostigmatid mites living on bark use many or most rainforest tree species, independent of bark roughness. These findings support the hypothesis that some epicorticolous Mesostigmata use tree trunks as ‘highways’ for dispersing between habitat patches, while others use it as a permanent habitat.