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Copyright of Naturaliste Canadien is the property of La Societe Provancher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Effects of Beauveria bassiana on non-target arthropods were assessed following field application on rangeland and alfalfa agroecosystems in Canada. Densities and prevalence of B. bassiana within non-target arthropods were measured by two methods, surface sanitation of non-target cadavers followed by homogenisation and plating on selective medium, or incubation in a high humidity environment. From rangeland, numbers of B. bassiana colony-forming units (cfu) in spiders, and carabid and tenebrionid beetles were low (≤2.0 × 103 cfu/ individual) and none of the 2500 arthropods incubated in high humidity were colonised. In alfalfa, increases in numbers of B. bassiana cfu in homogenised specimens were observed only in the first four days in coccinellid beetles (Coccinellidae) while high cfu numbers persisted in some harvestmen (Phalangidae). Laboratory assays with coccinellids indicated that recovered B. bassiana emanated from ingested conidia within the alimentary tracts rather than from hyphal bodies within hemocoels. A relatively low prevalence of non-target arthropods from which B. bassiana was isolated in rangeland and alfalfa coupled with the decrease in numbers of internal cfu as a function of time indicated that the fungus imparted a minor and short-lived impact on non-target arthropods. Although B. bassiana did not affect leafcutting bee larvae, prepupae or adult emergence following overwintering diapause, a small number of foraging bees were infected under field conditions. Measuring internal fungal populations on selective medium or incubation of cadavers in a high humidity environment were found to be convenient and efficient methods for safety assessment to non-target arthropods of a mycopesticide applied under field conditions. [ABSTRACT FROM AUTHOR]

Amber preserves an exceptional record of tiny, soft-bodied organisms and chemical environmental signatures, elucidating the evolution of arthropod lineages and the diversity, ecology, and biogeochemistry of ancient ecosystems. However, globally, fossiliferous amber deposits are rare in the latest Cretaceous and surrounding the Cretaceous-Paleogene (K-Pg) mass extinction. 1,2,3,4,5 This faunal gap limits our understanding of arthropod diversity and survival across the extinction boundary. 2,6 Contrasting hypotheses propose that arthropods were either relatively unaffected by the K-Pg extinction or experienced a steady decline in diversity before the extinction event followed by rapid diversification in the Cenozoic. 2,6 These hypotheses are primarily based on arthropod feeding traces on fossil leaves and time-calibrated molecular phylogenies, not direct observation of the fossil record. 2,7 Here, we report a diverse amber assemblage from the Late Cretaceous (67.04 ± 0.16 Ma) of the Big Muddy Badlands, Canada. The new deposit fills a critical 16-million-year gap in the arthropod fossil record spanning the K-Pg mass extinction. Seven arthropod orders and at least 11 insect families have been recovered, making the Big Muddy amber deposit the most diverse arthropod assemblage near the K-Pg extinction. Amber chemistry and stable isotopes suggest the amber was produced by coniferous (Cupressaceae) trees in a subtropical swamp near remnants of the Western Interior Seaway. The unexpected abundance of ants from extant families and the virtual absence of arthropods from common, exclusively Cretaceous families suggests that Big Muddy amber may represent a yet unsampled Late Cretaceous environment and provides evidence of a faunal transition before the end of the Cretaceous. • Big Muddy amber is the most diverse amber fauna close to the K-Pg mass extinction • The deposit was produced in an ancient subtropical swamp near remnants of a marine seaway • Two partial crown ants are preserved, filling a 16-million-year gap in the ant fossil record • The assemblage suggests a faunal turnover among insects prior to the K-Pg mass extinction Loewen et al. describe the most diverse amber deposit near the end-Cretaceous mass extinction. This newly discovered deposit, formed 1 million years before the extinction event, supports a faunal turnover among insects prior to the impact. Common Cretaceous insect families and genera appear to be replaced by modern taxa for lineages such as ants. [ABSTRACT FROM AUTHOR]

Flies (Diptera) are the dominant animal in the North yet are underrepresented in ecological studies. Our study aimed to examine the diversity patterns of the poorly documented acalyptrate flies across the Canadian North. Our main objective was to determine large- and small-scale drivers of species richness, abundance and community composition of acalyptrate fly assemblages. We collected flies at 12 Canadian sites in three ecoclimatic zones (Northern Boreal, Sub-Arctic and High Arctic), from two habitats (wet and mesic). We tested the effect of climatic variables and habitat on species richness and abundance using a generalized linear mixed-effects model, and on community composition using permutational multivariate analysis of variance. Species turnover between sites and ecoclimatic zones was examined by testing for multivariate homogeneity of group dispersions and visualised using non-metric multidimensional scaling. We identified 3631 acalyptrate flies, belonging to 333 species. Diversity measures and community composition were associated with seasonal and limiting temperature variables, consistent with the latitudinal diversity gradient seen in other animal groups. However, habitat only explained a small portion of the variation in our data, and only for observed species richness and species composition. Turnover patterns showed slight, statistically non-significant variation across zones. The High Arctic ecoclimatic zone was as spatially heterogenous in composition as the Northern Boreal and Sub-Arctic ecoclimatic zones but hinted at complex interplays between geographical and glacial legacies. Our results contradict the historical view of Arctic arthropod diversity as simple and uniform, and may serve as a baseline for future biodiversity monitoring. [ABSTRACT FROM AUTHOR]

Lyme disease, the most commonly reported vector-borne disease in North America, is caused by the spirochete Borrelia burgdorferi sensu stricto, which is transmitted by Ixodes scapularis in eastern Canada and Ixodes pacificus in western Canada. Recently, the northward range expansion of I. scapularis ticks, in south-eastern Canada, has resulted in a dramatic increase in the incidence of human Lyme disease. Detecting emerging areas of Lyme disease risk allows public health to target disease prevention efforts. We analysed passive tick surveillance data from Ontario and Manitoba to i) assess the relationship between the total numbers of I. scapularis submissions in passive surveillance from humans, and the number of human Lyme disease cases, and ii) develop province-specific acarological indicators of risk that can be used to generate surveillance-based risk maps. We also assessed associations between numbers of nymphal I. scapularis tick submissions only and Lyme disease case incidence. Using General Estimating Equation regression, the relationship between I. scapularis submissions (total numbers and numbers of nymphs only) in each census sub-division (CSD) and the number of reported Lyme disease cases was positively correlated and highly significant in the two provinces (P ≤ 0.001). The numbers of I. scapularis submissions over five years discriminated CSDs with ≥ 3 Lyme disease cases from those with < 3 cases with high accuracy when using total numbers of tick submission (Receiver Operating Characteristics area under the curve [AUC] = 0.89) and moderate accuracy (AUC = 0.78) when using nymphal tick submissions only. In Ontario the optimal cut-off point was a total 12 tick submissions from a CSD over five years (Sensitivity = 0.82, Specificity = 0.84), while in Manitoba the cut-off point was five ticks (Sensitivity = 0.71, Specificity = 0.79) suggesting regional variability of the risk of acquiring Lyme disease from an I. scapularis bite. The performances of the acarological indicators developed in this study for Ontario and Manitoba support the ability of passive tick surveillance to provide an early signal of the existence Lyme disease risk areas in regions where ticks and the pathogens they transmit are expanding their range. [ABSTRACT FROM AUTHOR]

Based on data presented in 29 papers published in the Biota of Canada Special Issue of ZooKeys and data provided herein about Zygentoma, more than 44,100 described species of terrestrial arthropods (Arachnida, Myriapoda, Insecta, Entognatha) are now known from Canada. This represents more than a 34% increase in the number of described species reported 40 years ago (Danks 1979a). The most speciose groups are Diptera (9620 spp.), Hymenoptera (8757), and Coleoptera (8302). Less than 5% of the fauna has a natural Holarctic distribution and an additional 5.1% are non-native species. A conservatively estimated 27,000-42,600 additional species are expected to be eventually discovered in Canada, meaning that the total national species richness is ca. 71,100-86,700 and that currently 51-62% of the fauna is known. Of the most diverse groups, those that are least known, in terms of percent of the Canadian fauna that is documented, are Acari (31%), Thysanoptera (37%), Hymenoptera (46%), and Diptera (32-65%). All groups but Pauropoda have DNA barcodes based on Canadian material. More than 75,600 Barcode Index Numbers have been assigned to Canadian terrestrial arthropods, 63.5% of which are Diptera and Hymenoptera. Much work remains before the Canadian fauna is fully documented, and this will require decades to achieve. In particular, greater and more strategic investment in surveys and taxonomy (including DNA barcoding) is needed to adequately document the fauna. [ABSTRACT FROM AUTHOR]

The emergence of the vector Ixodes scapularis in Ontario, Canada poses a significant public health risk. Both passive and active surveillance approaches have been employed by public health professionals (i.e., government employees) to monitor for the range expansion of this tick. Field surveillance using drag sampling for questing ticks is a recognized and effective method to identify reproducing tick populations. The degree of effort (i.e., number of visits per site) can enhance the sensitivity and specificity of surveillance, but increased effort conflicts with the cost to public health for field surveillance. Here we developed an indicator to determine the likelihood of I. scapularis establishment based on field sampling results. Field data from two established populations of I. scapularis in Ontario were incorporated with previous analyses of surveillance data to create the indicator, which is in the form of a scoring system. The life stage(s) collected, overall abundance and past surveillance findings from a site are all considered and a level is assigned for the likelihood of I. scapularis establishment based on current field sampling results. The likelihood levels are non-zero (i.e., no I. scapularis detected, but risk still present due to adventitious ticks), low, medium or high, and recommendations for future surveillance and public health measures are provided. The indicator was validated against field sampling results from five other established sites in the province and correctly categorized all five areas as high likelihood of establishment. The indicator was also applied to field sampling results from 36 sites of unknown status that were visited twice during the period of 2014–2016. There was substantial agreement of levels between measurements, as calculated using a weighted kappa. The indicator can assist public health professionals with the interpretation of field sampling results and direct their efforts for ongoing surveillance and public health interventions for I. scapularis-borne diseases, including Lyme disease. [ABSTRACT FROM AUTHOR]

Preventing the introduction and establishment of forest invasive alien species (FIAS) such as the Asian gypsy moth (AGM) is a high-priority goal for countries with extensive forest resources such as Canada. The name AGM designates a group of closely related Lymantria species (Lepidoptera: Erebidae: Lymantriinae) comprising two L. dispar subspecies (L. dispar asiatica, L. dispar japonica) and three closely related Lymantria species (L. umbrosa, L. albescens, L. postalba), all considered potential FIAS in North America. Ships entering Canadian ports are inspected for the presence of suspicious gypsy moth eggs, but those of AGM are impossible to distinguish from eggs of innocuous Lymantria species. To assist regulatory agencies in their identification of these insects, we designed a suite of TaqMan® assays that provide significant improvements over existing molecular assays targeting AGM. The assays presented here can identify all three L. dispar subspecies (including the European gypsy moth, L. dispar dispar), the three other Lymantria species comprising the AGM complex, plus five additional Lymantria species that pose a threat to forests in North America. The suite of assays is built as a “molecular key” (analogous to a taxonomic key) and involves several parallel singleplex and multiplex qPCR reactions. Each reaction uses a combination of primers and probes designed to separate taxa through discriminatory annealing. The success of these assays is based on the presence of single nucleotide polymorphisms (SNPs) in the 5’ region of mitochondrial cytochrome c oxidase I (COI) or in its longer, 3’ region, as well as on the presence of an indel in the “FS1” nuclear marker, generating North American and Asian alleles, used here to assess Asian introgression into L. dispar dispar. These assays have the advantage of providing rapid and accurate identification of ten Lymantria species and subspecies considered potential FIAS. [ABSTRACT FROM AUTHOR]

Powassan virus (POWV) is a tick-borne flavivirus that can result in a severe neuroinvasive disease with 50% of survivors displaying long-term neurological sequelae. Human POWV cases have been documented in Canada, the United States, and Russia. Although the number of reported POWV human cases has increased in the past fifteen years, POWV remains one of the less studied human pathogenic flaviviruses. Ixodes ticks are the vectors for POWV, and the virus is transmitted to a host’s skin very early during the tick feeding process. Central to the successful transmission of a tick-borne pathogen are complex interactions between the host immune response and early tick-mediated immunomodulation, all of which initially occur at the skin interface. In our prior work, we examined the cutaneous immune gene expression during the early stages of POWV-infected Ixodes scapularis feeding. The present study serves to further investigate the skin interface by identifying early cell targets of infection at the POWV-infected tick feeding site. An in vivo infection model consisting of POWV-infected ticks feeding on mice for short durations was used in this study. Skin biopsies from the tick feeding sites were harvested at various early time points, enabling us to examine the skin histopathology and detect POWV viral antigen in immune cells present at the tick feeding site. The histopathology from the present study demonstrates that neutrophil and mononuclear cell infiltrates are recruited earlier to the feeding site of a POWV-infected tick versus an uninfected tick. This is the first report demonstrating that macrophages and fibroblasts contain POWV antigens, which suggests that they are early cellular targets of infection at the tick feeding site. These data provide key insights towards defining the complex interactions between the host immune response and early tick-mediated immunomodulation. [ABSTRACT FROM AUTHOR]

The Canadian Forest Invasive Alien Species (CanFIAS) database provides point records of alien arthropod (insects and mites) and pathogen (fungi) species found on trees in Canada extracted from more than 100 years of national surveys. Each record includes a species identification, location, year of observation, and host association and is linked electronically to its original source. More than 175 000 records of 329 alien arthropod species and 11 plant pathogens are available. Historical rates of detection, as indicated by first records, were greatest in the decades following the two world wars. The overall rate has been approximately three species per year since 1900. Richness of alien species is greatest in the Coastal and Great Lakes-St. Lawrence forest ecozones and lowest in the Subalpine and Tundra ecozones. The alien species most significant in terms of extent of invasion and damage to trees are tree-host specialists, feeding on or infecting mostly one or two genera in a single plant family. Important commercial trees including pine, spruce, poplar, and birch and amenity genera including willow, cherry, and maple host the greatest diversity of alien species. Sap-feeding insects are the most speciose feeding group, but foliage-feeding and wood-boring insects and plant pathogens cause the most damage. [ABSTRACT FROM AUTHOR]

Circum-Laurentian middle Cambrian (Cambrian Series 3) deposits in Greenland and British Columbia yield a new hipponicharionid bradoriid arthropod, Flumenoglacies n. gen., characterized by a comarginal, ramp-like structure which is crested by a continuous lobe. The narrow lobe is the result of the medial fusion of anterior and posterior lobes, seemingly a recurrent theme in hipponicharionid evolution. The type species, F. groenlandica n. sp., is described from the Ekspedition Brae Formation (Drumian Stage) of Peary Land but the description of two unnamed species from slightly older middle Cambrian strata of the Stephen Formation of British Columbia provides additional evidence for the wide distribution of Small Shelly Faunas during the Cambrian. [ABSTRACT FROM AUTHOR]

We identified ticks submitted by the public from 2008 through 2012 in Ontario, Canada, and tested blacklegged ticks Ixodes scapularis for Borrelia burgdorferi and Anaplasma phagocytophilum. Among the 18 species of ticks identified, I. scapularis, Dermacentor variabilis, Ixodes cookei and Amblyomma americanum represented 98.1% of the 14,369 ticks submitted. Rates of blacklegged tick submission per 100,000 population were highest in Ontario's Eastern region; D. variabilis in Central West and Eastern regions; I. cookei in Eastern and South West regions; and A. americanum had a scattered distribution. Rates of blacklegged tick submission per 100,000 population were highest from children (0–9 years old) and older adults (55–74 years old). In two health units in the Eastern region (i.e., Leeds, Grenville & Lanark District and Kingston-Frontenac and Lennox & Addington), the rate of submission for engorged and B. burgdorferi-positive blacklegged ticks was 47× higher than the rest of Ontario. Rate of spread for blacklegged ticks was relatively faster and across a larger geographic area along the northern shore of Lake Ontario/St. Lawrence River, compared with slower spread from isolated populations along the northern shore of Lake Erie. The infection prevalence of B. burgdorferi in blacklegged ticks increased in Ontario over the study period from 8.4% in 2008 to 19.1% in 2012. The prevalence of B. burgdorferi-positive blacklegged ticks increased yearly during the surveillance period and, while increases were not uniform across all regions, increases were greatest in the Central West region, followed by Eastern and South West regions. The overall infection prevalence of A. phagocytophilum in blacklegged ticks was 0.3%. This study provides essential information on ticks of medical importance in Ontario, and identifies demographic and geographic areas for focused public education on the prevention of tick bites and tick-borne diseases. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new arthropod, Kootenichela deppi n. gen. n. sp., is described from the Stanley Glacier exposure of the middle Cambrian (Series 3, Stage 5) Stephen Formation in Kootenay National Park (British Columbia, Canada). This taxon possesses a number of primitive arthropod features such as an elongate, homonomous trunk (consisting of at least 29 segments), poorly sclerotised trunk appendages, and large pedunculate eyes associated with an anterior (ocular) sclerite. The cephalon encompasses a possible antenna-like appendage and enlarged raptorial appendages with a bipartite peduncle and three spinose distal podomeres, indicative of megacheiran ("great-appendage" arthropod) affinities. The relationships of megacheirans are controversial, with them generally considered as either stem-euarthropods or a paraphyletic stem-lineage of chelicerates. An extensive cladistic analysis resolved Kootenichela as sister-taxon to the enigmatic Worthenella cambria from the middle Cambrian (Series 3, Stage 5), Burgess Shale Formation in Yoho National Park (British Columbia), which is herein reinterpreted as a megacheiran arthropod. Based on their sister-group relationship, both taxa were placed in the new family Kootenichelidae, to which Pseudoiulia from the Chengjiang biota is also tentatively assigned. All of these taxa possess an elongate, multi-segmented body and subtriangular exopods. This family occupies a basal position within a paraphyletic Megacheira, the immediate outgroup of Euarthropoda (crown-group arthropods). The resultant topology indicates that analyses that have resolved megacheirans as stem-chelicerates have done so because they have rooted on inappropriate taxa, e.g., trilobitomorphs and marrellomorphs. [ABSTRACT FROM AUTHOR]

Spotted fever group rickettsioses (SFGR) are infections caused by established and emerging human pathogens worldwide. These rickettsial agents are transmitted to humans via arthropods and may result in mild to severe and potentially fatal diseases. Spotted fever group rickettsioses are characterized by similar clinical features, including fever, rash, headache and myalgias, with the development of an inoculation eschar in many, but not all cases. Endemic rickettsial infections do occur but are infrequent in Canada, in contrast to the United States, where these infections are far more prevalent. Travel-associated rickettsioses, however, are being diagnosed with increasing frequency in Canadian travellers returning from international trips abroad, in particular in travellers returning from Africa. The diagnosis of rickettsial infections can be challenging owing to the non-specific nature of the clinical symptoms and the requirement for specialized testing. Serology cannot distinguish between the approximately 20 spotted fever group rickettsial species currently known or suspected to be capable of causing human infection. Molecular testing is required to determine the rickettsial species responsible for infection, but requires greater effort on the part of the clinician to collect appropriate samples, including cutaneous skin swabs from under the eschar or skin punch biopsies of the eschar or rash. Infections with spotted fever group rickettsiae likely occur more commonly than currently recognized and should be considered in patients with appropriate symptoms and exposure histories. [ABSTRACT FROM AUTHOR]

Optimal foraging theory predicts organisms will forage in habitats providing the most profitable prey. Human alterations to ecosystems may affect predators' foraging activity by changing landscape features, prey types, and prey availability. Assessing the selection of foraging habitats in a heterogeneous landscape can provide data to improve land management and conservation policies. In Canada, the pallid bat ( (LeConte, 1856); Vespertilionidae) is listed as threatened partly because of loss or modification of shrub-steppe habitat. Our purpose was to determine if vineyards provide a suitable surrogate for foraging habitat relative to native habitat. We used pitfall traps to compare prey abundance in each habitat and analyzed faeces to assess diet composition. Over 24 nights, we surveyed both habitats for foraging bats. Bats foraged over vineyards, but we recorded significantly more foraging activity over native habitat. We collected over 2000 arthropods in pitfall traps and found significantly more in native habitat compared with vineyards. Species eaten by pallid bats were present in both habitats. Scarab beetles (Coleoptera: Scarabidae) and Jerusalem crickets (Orthopthera: Stenopelmatidae) represented the principal prey. The use of vineyards by pallid bats for foraging suggests that while they are adapting to a changing landscape, reduced prey abundance in vineyards may negatively affect them over the long term. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent genome size estimates for Arctic amphipods have revealed the largest genomes known in the Crustacea. Here we provide additional data for 7 species of caridean shrimp collected from the Canadian Arctic and the Gulf of St. Lawrence. Genome sizes were estimated by flow cytometry and haploid C-values ranged from 8.53 ± 0.30 pg in Pandalus montagui (Pandalidae) to 40.89 ± 1.23 pg in Sclerocrangon ferox (Crangonidae). The value for S. ferox represents the largest decapod genome yet recorded and indicates a 38-fold variation in genome size within this order. These data suggest that large genomes may be relatively common in Arctic crustaceans, and underline the need for further comparative studies. [ABSTRACT FROM AUTHOR]

The middle Silurian Eramosa Lagerstätte of Ontario, Canada, preserves taxonomically and taphonomically diverse biotas including articulated conodont skeletons and hetero stracan fish, annelids and arthropods with soft body parts, and a diverse marine flora. Soft tissues are preserved as calcium phosphate and carbon films, the latter possibly stabilized by early diagenetic sulfurization. It is significant that the biotas also include a decalcified, autochthonous shelly marine fauna, and trace fossils. This association of exceptionally preserved and more typical fossils distinguishes the Eramosa from other Silurian shallow-marine Lagerstätten, such as the Waukesha Lagerstätte, and suggests that the Eramosa is not the product of exceptional preservation in an atypical environment, a bias claimed for many post-Cambrian Lagerstätten. The Eramosa Lagerstätte may provide a more reliable, balanced measure of what has been lost from the Silurian fossil record. [ABSTRACT FROM AUTHOR]

Fungi from approximately 1700 individual arthropods that had been captured in traps set in aspen-dominated woodland in western Canada and baited with coyote dung, moose dung, white-rotted wood, brown-rotted wood and fiberglass were isolated in pure culture and identified. These data were analysed with principal components analysis (PCA) to determine whether different types of substrate attracted specific arthropods and whether these animals carried unique assemblages of fungi with known proclivities for the new habitat. Mycobiotic agar was used to restrict the numbers of fungi isolated and resulted in the recovery of 1687 isolates representing 65 species across 12 orders. Isolates of cosmopolitan fungal taxa such as species of Cladosporium, Penicillium, and Beauveria were the most numerous. Taxa with predilections for specific substrates, such as Myxotrichum and Cryptendoxyla that are known inhabitants of cellulose-rich materials (i.e. rotted wood), and various representatives of the keratinophilic Onygenales were recovered from arthropods attracted respectively to baits rich in cellulose and keratin. When traps were analysed according to the identity and numbers of arthropods captured, there was considerable overlap among clusters representing specific bait types, with traps baited with coyote dung being the most divergent partly because they captured significantly more arthropods than those baited with moose dung or rotted wood. When bait type was examined according to the identity and numbers of fungi on trapped arthropods the degree of overlap was also high although a few trends could be discerned. In particular traps baited with brown-rotted wood and coyote dung diverged slightly indicating that arthropods visiting these bait types were carrying somewhat different suites of fungi. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The discovery of a new naraoiid nektaspid in the Upper Silurian (Pridolian) of southeastern Ontario significantly extends the range of this unusual group. Nektaspids are nonmineralized arthropods typical of Early and Middle Cambrian soft-bottom communities, but were thought to have become extinct in the Late Ordovician. The unique holotype specimen of Naraoia bertiensis n. sp. comes from a Konservat-Lagerstätte deposit renowned for its eurypterid fauna (the Williamsville Member of the Bertie Formation). Naraoia bertiensis lacks thoracic segments and is morphologically similar to Naraoia compacta from the Middle Cambrian Burgess Shale, save for the presence of a long ventral cephalic doublure and a subtly pointed posterior shield. To examine the phylogenetic relationships of the new naraoiid, we coded characters of the holotype specimen and of nine previously described nektaspids. The results confirm a sister taxon relationship between Naraoia compacta and Naraoia bertiensis and the monophyly of nektaspid forms lacking thoracic segments (family Naraoiidae). This latter group may have arisen from an ancestral segment-bearing form through heterochronic loss of thoracic segments early in the Cambrian. The disjunct occurrence of a naraoiid nektaspid in the Late Silurian resembles the reappearance of other "Lazarus taxa" that were thought to have been eliminated during mass extinction events. The naraoiid lineage survived the Late Ordovician biotic crisis, but in this case the "Lazarus effect" seems likely to be taphonomic in origin. [ABSTRACT FROM AUTHOR]

The bradoriids Hipponicharion aff. hispanicum and Wimanicharion aff. matthewi are reported from the lower and middle Cambrian strata of the Cadenas Ibe´ricas, Spain. The genus Hipponicharion seems to be restricted to the Acadobaltic Province. Wimanicharion has been recorded from Sweden and Canada (Nova Scotia). The new discovery of Wimanicharion in Spain indicates its similar palaeobiogeographical distribution to Hipponicharion. [Copyright &y& Elsevier]

West of the Fossil Gully Fault Zone on Mount Stephen, the three lowest members only of the Burgess Shale Formation are preserved: the Kicking Horse Shale, the Yoho River Limestone, and the Campsite Cliff Shale. The formation rests unconformably upon the Takakkaw Tongue Formation, whose dark basinal limestones conformably overlie paler shelf-like limestones of the Mount Whyte Formation. Mapping has resolved a long-standing problem and shown that the stratigraphical position of the famous Mount Stephen Trilobite Beds lies within the Campsite Cliff Shale. It has also revealed some of the complexities of the Fossil Gully Fault Zone, among which different periods and directions of component fault movements are indicated. Faunal evidence shows that the Plagiura–Kochaspis to Albertella and Albertella to Glossopleura zonal boundaries lie within the Takakkaw Tongue sequence. Within the Burgess Shale, three distinct soft-bodied communities occur at different stratigraphical levels on this mountain slope. The oldest, characterized by the arthropod Alalcomenaeus and chelicerate Sanctacaris, occurs low in the Kicking Horse Shale Member and is best known from Collins Quarry. The others lie within the Campsite Cliff Shale Member. The Trilobite Beds, characterized by claws of the dinocarid Anomalocaris and moults of the trilobite Ogygopsis klotzi, onlap the sloping top of a proximal bench facies of the Yoho River Limestone Member close to the Cathedral Escarpment. Slightly older and farther out in the basin are beds characterized by the dinocarid Laggania and a tulip-like animal related to Dinomischus, excavated about 12 m above the top of a thin distal wedge facies of the Yoho River Limestone at the S7 site. Among the illustrated trilobites, a new corynexochine from the Campsite Cliff Shale Member is figured. [ABSTRACT FROM AUTHOR]

Deals with a study which demonstrated that the phytophagous arthropod pest fauna in two commercial vineyards in southwestern Quebec was qualitatively and quantitatively different than that of Ontario and New York state. Background to the study; Materials and methods; Results and discussion.

The largest known trilobite fossil, a virtually complete articulated dorsal shield of the asaphid Isotelus rex new species, has been recovered from Upper Ordovician (Cincinnatian, Richmondian) nearshore carbonates of the Churchill River Group in northern Manitoba. At over 700 mm in length, it is almost 70 percent longer than the largest previously documented complete trilobite, and provides the first unequivocal evidence of maximum trilobite length in excess of one-half metre. Comparisons with other fossil and extant members of the phylum suggest that in terms of maximum linear dimensions it was among the biggest arthropods ever to have lived. Sediments of the Churchill River Group were deposited in an equatorial epeiric setting and the extremely large size of I. rex n. sp. thus marks a striking example of low-latitude gigantism, in sharp contrast to the widespread phenomenon of "polar gigantism" in many modern marine benthic arthropods. Lack of extensive epibiontic colonization of the exoskeletal surface and the presence of large distinctive trace fossils in the same unit suggest that I. rex n. sp. may have been a semi-infaunal predator and scavenger that employed a shallow furrowing and probing mode of benthic feeding. The extinction of the isotelines (and virtually the entire asaphide lineage) at the end of the Ordovician cannot be related to the near contemporaneous achievement of exceptionally large adult size in some representatives. Failure to survive the terminal Ordovician extinction event was most likely a consequence of a pelagic larval life-style that proved ill-adapted to the rapid onset of global climatic cooling and loss of tropical shelf habitats. [ABSTRACT FROM AUTHOR]

Investigation of a small number of samples with representatives of the genus Diaphanosoma from the cladoceran collection of the National Museum of Natural History, Smithsonian Institution (Washington, D.C., U.S.A.) has revealed two new species, D. freyi and D. heberti, from Louisiana-Missouri and Newfoundland, respectively. The former looks like one of the most primitive species of the genus. Two other species, D. fluviatile and D. brevireine, are recorded from the southern United States for the first time. Members of the D. brachyuruin and D. birgei species groups, which are morphologic ally variable and need further detailed investigations, were represented in the bulk of the material studied. The species richness of the genus in North America appears to be high and its composition is obviously complex but remains little studied. [ABSTRACT FROM AUTHOR]

Examines the presence of arthropod-produced fossil trackways extending the record of the first arthropod landfall at the basal terrestrial deposits in Kingston, Ontario. Colonization of land during prehistoric era; Traces of the fossils; Occurrence of trackways in an inactive quarry.

Ecological theory suggests that along productivity gradients, abundances of organisms within trophic levels will increase in a stepwise pattern from producers to consumers. To test this theory I investigated changes in abundance of soil arthropods at three trophic levels: microphytophages, represented by Collembola, predacious mites (Acari) that feed on Collembola, and three groups of macroarthropods (spiders, ants, and centipedes) that were observed to feed on mites. Changes in abundance were monitored along a gradient in vegetation structure from grass to shrub to forest in the Canadian prairies. I controlled for temporal variation in abundance among years and surveys within a year. As predicted, (i) numbers of Collembola did not change with increases in productivity; (ii) mite numbers were greatest in the shrublands; and (iii) numbers of macroarthropod predators increased from grassland to shrubland, and there was a nonsignificant increase in numbers of spiders and centipedes in forest habitat. Contrary to predictions, macroarthropod numbers were not significantly greater in forest habitat, and ant numbers actually declined. Possible explanations for the lack of increase in macroarthropod predator abundance in the forest habitat with the greatest productivity include decreased ground-level humidity and greater abundance of macroarthropod predators and parasites in forest environments.La théorie écologique veut que, le long de gradients de productivité, l'abondance des organismes des différents niveaux trophiques augmente en escalier, des producteurs aux consommateurs. Pour éprouver cette hypothèse, j'ai suivi les changements dans l'abondance des arthropodes du sol à trois niveaux trophiques : les microphytophages, représentés par les collemboles, les acariens prédateurs (Acari) qui se nourrissent de collemboles et trois groupes de macroarthrhopodes (araignées, fourmis, centipèdes) qui consomment des acariens. Les variations de l'abondance ont été enregistrées le long d'un gradient dans la structure de la végétation, des herbes aux buissons aux forêts dans les Prairies canadiennes. J'ai tenu compte de la variation temporelle de l'abondance d'une année à l'autre et d'un inventaire à un autre au cours d'une même année. Tel que prévu, (i) le nombre de collemboles n'a pas varié malgré l'augmentation de la productivité; (ii) le nombre d'acariens était maximal dans les zones buissonneuses; (iii) le nombre de macroarthropodes prédateurs était plus élevé dans la zone buissonneuse que dans la zone herbeuse et le nombre d'araignées et de centipèdes était plus élevé, mais pas de façon significative, dans la forêt. Contrairement aux prédictions, le nombre de macroarthropodes n'était pas significativement plus élevé en forêt et le nombre de fourmis était même inférieur. Parmi les raisons qui peuvent expliquer pourquoi l'abondance des macroarthropodes prédateurs n'augmente pas en milieu forestier où la productivité est maximale, il faut penser à la diminution de l'humidité au niveau du sol et à l'augmentation des macroarthropodes prédateurs et parasites en milieu forestier.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Leptodiaptomus sicilis (S. A. Forbes 1882) in Pyramid Lake, Alberta, Canada, has only one main generation per year. A small summer generation probably does not survive. Adults may persist for 7 to 12 months, and individual copepods may live for up to 17 months. Retardation of the development of copepodid C 4 and C 5 seems lo be food linked. The high percentage of survivors (up to 97%) from the first egg pulse of the main generation, and the low percentage of survivors (as low as 3%) from the second egg pulse, is likely due to the absence of cyclopoid adults and copepodids in spring, and to both cyclopoid predation and a poor food regime in summer. Production estimates by several methods gave closely comparable results. Mean daily production by L. sicilis is 0.29 mg dry weight m-3, and the annual P/B ratio is 2.63. [ABSTRACT FROM AUTHOR]

Information about the topics at the symposium entitled "Maintaining Arthropods in Northern Forest Ecosystem" on November 24, 2005 in Canada is presented. The event reviewed and synthesized information about the structure and dynamics of arthropod assemblages from North American forest. The symposium featured several contributors from across the country and compared the results of their study on terrestrial arthropods.

1. van Duinen et al. ( Freshwater Biol., 2006) raise an interesting point regarding Mazerolle et al.’s ( Freshwater Biol., 2006, 51, p. 333) conclusion on the ability of invertebrates, especially sedentary species, to colonise newly created bogs pools. We wish to clarify that Mazerolle et al. (2006) targeted large arthropods and the absence of smaller sedentary species was purely a result of sampling design. 2. van Duinen et al. (2006) postulate that colonisation rates by bog specialists should be higher in Canada than in the Netherlands, given the extensive amount of intact peatlands in Canada. Here, we emphasise the importance of taking the regional context into account when assessing restoration success as our study site occurs in a landscape where most bog pools have been drained. 3. An evaluation of restoration efforts should focus on both sedentary and vagile invertebrates, to resolve the importance of persistence and colonisation. Such patterns are difficult to interpret, however, when sampling designs and analyses do not account for the probability of detection: an absence may be due to non-detection or true absence. We strongly urge investigators to directly estimate detection probability in addition to the parameters of interest (e.g. presence, abundance) to provide the best information possible regarding restoration success. [ABSTRACT FROM AUTHOR]

An introduction is presented which discusses the contents within the issue including articles on topics such as the success of the Biological Survey of Canada (BSC), the Arthropods of Canadian Grasslands project of the BSC, and the use of old species lists to know about faunistic patterns.

Reports on the discovery of fossils of large land-dwelling arthropods in Canada. Evidence of the oldest large animals living on land in North America; Proof leading scientists to confirm as land dwellers.