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Simulioidea are extremely rare in the fossil record of the Mesozoic, when members of Culicomorpha originated. Based on numerous compressions from the Cretaceous of Asia (Khasurty and Baissa, Wester...

The Canadian Diptera fauna is updated. Numbers of species currently known from Canada, total Barcode Index Numbers (BINs), and estimated numbers of undescribed or unrecorded species are provided for each family. An overview of recent changes in the systematics and Canadian faunistics of major groups is provided as well as some general information on biology and life history. A total of 116 families and 9620 described species of Canadian Diptera are reported, representing more than a 36% increase in species numbers since the last comparable assessment by JF McAlpine et al. (1979). Almost 30,000 BINs have so far been obtained from flies in Canada. Estimates of additional number of species remaining to be documented in the country range from 5200 to 20,400.

Coalescent-based analyses have been recommended for species delimitation and tree reconstruction. Yet, despite recent advances in molecular methods, acquiring sufficient genetic data often precludes coalescent-based analyses in nonmodel organisms. We show that these methods are accessible to questions in nonmodel systems. Specifically, we use coalescent-based analyses to investigate evolutionary independence and relationships among chromosomally distinct members (sibling species) of a black fly (Diptera: Simuliidae) species complex. Our dataset consists of nuclear DNA (nuDNA) and mitochondrial DNA (mtDNA) markers – the former developed using the black fly transcriptome and available genomes from model relatives. We show that individual gene trees exhibit considerable discordance among one another and reveal little about potential species limits. Consistent species tree topologies are obtained from analyses of nuDNA, both with and without the inclusion of mtDNA data. Nodes on the tree receive robust support with the addition of mtDNA. Coalescent-based species validation approaches recognize all sibling species. However, unlike species tree analyses, the addition of mtDNA data does not improve or alter the results. Thus, analyses of nuDNA alone can validate sibling species. Contrary to these results, population genetic patterns of neutral diversity, within-locus recombination, and linkage disequilibrium suggest that sibling species represent a single species with high levels of nucleotide polymorphism, large effective population sizes, and extensive gene flow. Demographic patterns inferred from neutrality tests integrate seemingly disparate results by showing signatures of gene flow among structured populations that are expanding in size. Thus, admixture associated with geographic range expansions may be assimilating sibling species into a single genetic lineage.

Indirect impacts of climate change, mediated by new species interactions (including pathogens or parasites) will likely be key drivers of biodiversity reorganization. In addition, direct effects of extreme weather events remain understudied. Simultaneous investigation of the significance of ectoparasites on host populations and extreme weather events is lacking, especially in the Arctic. Here we document the consequences of recent black fly outbreaks and extreme precipitation events on the reproductive output of an arctic top predator, the peregrine falcon (Falco peregrinus tundrius) nesting at the northern range limit of ornithophilic black flies in Nunavut, Canada. Overall, black fly outbreaks and heavy rain reduced annual nestling survival by up to 30% and 50% respectively. High mortality caused by ectoparasites followed record-breaking spring snow precipitation, which likely increased stream discharge and nutrient runoff, two key parameters involved in growth and survival of black fly larvae. Using the RCP4.5 intermediate climate scenario run under the Canadian Global Climate Model, we anticipate a northward expansion of black fly distribution in Arctic regions. Our case study demonstrates that, in the context of climate change, extreme weather events can have substantial direct and indirect effects on reproductive output of an arctic top-predator population.

Two species of Australian Simuliidae known only from adult females and currently assigned to "Paracnephia" are re-described, as are their now-known males and immature stages. Morphological character states of "Paracnephia" fergusoni (Tonnoir) and "P." fergusoni var. (Mackerras & Mackerras) reveal that they are markedly distinct from all other Australian species, and are here assigned to the new genus—Nothogreniera—the most plesiomorphic Gondwanan Australian simuliid. Structural variation among populations of N. fergusoni suggests that this entity comprises a species complex.

Moulton, John K., Currie, Douglas C., Craig, Douglas A. (2018): A New Genus, Ectemnoides, for Seven Species of Australian Gondwanan Simuliidae (Diptera) With Description of a Novel Form of Larval Attachment. Insect Systematics and Diversity 2 (4), No. 4: 1-54, DOI: 10.1093/isd/ixy009, URL: http://dx.doi.org/10.1093/isd/ixy009

Chromosome inversions may be involved in adaptation and speciation. We investigate ecological diversification among members of the Simulium arcticum species complex at different stages of chromosome divergence. Our analyses focus on two geographical scales. First, we assess ecological divergence of sibling species throughout North America using niche modelling methods. Then, using canonical correspondence analysis, we investigate habitat associations of sibling species and cytotypes in the northern Rocky Mountains ecoregion, where cytotypes tend to occur. Despite significant overlap in predicted distributions, all sibling species are ecologically unique. On the other hand, we discover various degrees of ecological divergence for cytotypes. Some cytotypes are ecologically distinct and perhaps are in their initial stages of incipient speciation. Other cytotypes are ecologically associated with one another or with particular sibling species. Thus, for members of the S. arcticum complex, ecological and chromosomal differences tend to develop early in lineage formation. Ecological distinctiveness of sibling species and cytotypes suggests that local adaptation may be involved in diversification of these chromosomal forms. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115, 13‐27.

With new material available of most stages of many known Australian Paracnephia, including new species, it is now clear that certain segregates warrant assignment to new genera. This applies to Paracnephia gladiator Moulton & Adler, a Western Australia simuliid with numerous unique character states. The species is fully redescribed and assigned to Bunyipellum nov. gen. A diagnosis is provided and relationships discussed, as is historical biogeography. Bunyipellum appears to be more closely related to elements of the South American simuliid fauna than to any other Gondwanan Australian species.

The hitherto monotypic South American genus Paraustrosimulium Wygodzinsky & Coscarón is revised to accommodate two Australian species: Austrosimulium colboi Davies & Györkös and Paraustrosimulium obcidens n. sp. The generic diagnosis is updated and the eastern Australian species Paraustrosimulium colboi (Davies & Györkös) n. stat. is re-described, including the male for the first time. The Western, Australian sister species of P. colbo, namely P. obcidens Craig, Moulton Currie n. sp. is also fully described. The relationship of Paraustrosimulium to other simuliid genera is discussed, as are aspects of historical biogeography.

Arctic and subarctic environments are among the most inaccessible regions in the world, making biological surveys difficult to conduct. Thus, the insect fauna of these regions has remained inadequately surveyed. The aquatic insect orders Ephemeroptera, Plecoptera, and Trichoptera (EPTs) are particularly abundant and diverse at high latitudes, playing key roles in trophic chains where nutrients are scarce. However, particular aspects of their life cycle make them difficult to study. Specifically, species-level identification requires last-instar larvae or adults which, because they are short lived, are typically not available for all taxa during a particular collecting event. With the initial goal of surveying the biodiversity of these insect groups, we sampled ca.10,000 EPT specimens from 12 locations across northern Canada over two years. Approximately 800 of these were subsequently selected for COI DNA barcoding. Overall, we identified 155 EPT species (58 Ephemeroptera, 41 Plecoptera, 56 Trichoptera) based on a 2% divergence criterion. Compared to other similar studies on EPTs we found higher (particularly among the Plecoptera and Ephemeroptera) and more even diversity, potentially reflecting environmental differences in sampling localities. We further assessed phylogeographic divergence patterns among seven species, finding that eastern and western populations diverged during the Pleistocene Epoch (

Arctic and subarctic environments are among the most inaccessible regions in the world, making biological surveys difficult to conduct. Thus, the insect fauna of these regions has remained inadequately surveyed. The aquatic insect orders Ephemeroptera, Plecoptera, and Trichoptera (EPTs) are particularly abundant and diverse at high latitudes, playing key roles in trophic chains where nutrients are scarce. However, particular aspects of their life cycle make them difficult to study. Specifically, species-level identification requires last-instar larvae or adults which, because they are short lived, are typically not available for all taxa during a particular collecting event. With the initial goal of surveying the biodiversity of these insect groups, we sampled ca.10,000 EPT specimens from 12 locations across northern Canada over two years. Approximately 800 of these were subsequently selected for COI DNA barcoding. Overall, we identified 155 EPT species (58 Ephemeroptera, 41 Plecoptera, 56 Trichoptera) based on a 2% divergence criterion. Compared to other similar studies on EPTs we found higher (particularly among the Plecoptera and Ephemeroptera) and more even diversity, potentially reflecting environmental differences in sampling localities. We further assessed phylogeographic divergence patterns among seven species, finding that eastern and western populations diverged during the Pleistocene Epoch (

Comparative analyses of populations at different stages of divergence can yield insights into the process of speciation. We assess population structure, gene flow, and maternal ancestry at five locations containing sympatric members of the Simulium arcticum complex at different stages of chromosome divergence. We analyze both nuclear and mitochondrial DNA markers, including 11 microsatellite loci, as well as COI, COII, cytb, and ND4 gene sequences. Simulium negativum, representing the later stages of divergence, shows both nuclear and mitochondrial differentiation when compared with allopatric and sympatric chromosomal forms, as well as both low contemporary and historical gene flow in sympatry. At intermediate stages of chromosome divergence, populations differ at nuclear, but not mitochondrial, loci in allopatry and sympatry. In one comparison of intermediate stage chromosomal forms (S. arcticum sensu stricto and S. apricarium), populations demonstrate low contemporary, but higher historical, gene flow in sympatry. In a second sympatric comparison (S. arcticum s. s. and S. brevicercum), both contemporary and historical gene flow are high. All analyses of sympatric populations at the earliest stages of chromosome divergence demonstrate panmixia; yet, some nuclear differentiation in allopatry is apparent. These findings suggest that molecular divergence is tracking chromosome divergence along a chromosomally-defined continuum of speciation in black flies.

Mitochondrial based phylogenetic reconstructions often show deviations from species-level monophyly. We used the Simulium arcticum species complex (Diptera: Simuliidae) as a model system for interpreting non-monophyly in light of chromosomal data supporting species status of siblings. For cytogenetic identification of morphologically indistinguishable black fly sibling species, larvae must be preserved in Carnoy's solution, a fixative known to degrade DNA. Consequently, we reconstructed phylogenetic relationships based on 12S, COII, cyt b, and ITS-1 gene sequences obtained from larvae sampled from presumed taxon-pure localities. As species composition at 'taxon-pure' sites may have changed at the time of sampling, we performed a second study that aimed to: (1) assess phylogenetic relationships among cytologically verified members of the S. arcticum species complex using COI and COII gene sequences; (2) determine whether useable genetic information could be gleaned from Carnoy's fixed specimens; and (3) determine the extent to which Carnoy's fixative degrades DNA over time. We consistently obtained genetic data from material stored in Carnoy's solution for two to three months. Genetic analysis of samples fixed in Carnoy's solution for up to six years indicates that larvae preserved for a maximum of five years can provide useable information for molecular analysis. Our preliminary and cytologically confirmed phylogenetic analyses demonstrate that mitochondrial DNA fails to resolve species-level monophyly of chromosomally distinct S. arcticum taxa. As results of analyses based on cytologically verified larvae mirror those of our preliminary study, we rule out imperfect taxonomy as the reason for species-level non-monophyly. Although we cannot confidently reject either inadequate phylogenetic information or incomplete lineage sorting as the cause of non-monophyly, the sharing of alleles between sympatric siblings suggests introgressive hybridization between taxa. We conclude that the patterns present in the S. arcticum phylogeny likely represent the initial stages of chromosome based sibling speciation.