Douglas C. Currie

Global diversity of black flies (Diptera: Simuliidae) in freshwater

Black flies are a worldwide family of nematocerous Diptera whose immature stages are confined to running waters. They are key organisms in both aquatic and terrestrial ecosystems, but are perhaps best known for the bloodsucking habits of adult females. Attacks by black flies are responsible for reduced tourism, deaths in wild and domestic birds and mammals, and transmission of parasitic diseases to hosts, including humans. About 2,000 nominal species are currently recognized; however, certain geographical regions remain inadequately surveyed. Furthermore, studies of the giant polytene chromosomes of larvae reveal that many morphologically recognized species actually consist of two or more structurally indistinguishable (yet reproductively isolated) sibling species. Calculations derived from the best-known regional fauna—the Nearctic Region—reveal that the actual number of World black fly species exceeds 3,000.

Phylogeny of the water strider genus Rheumatobates (Heteroptera: Gerridae)

The genus Rheumatobates comprises thirty‐seven species and subspecies of New World water striders belonging to subfamily Rhagadotarsinae. Among species, males vary dramatically in the degree and nature of modifications of the antennae, three pairs of legs and abdominal and genital segments. Characters describing this modification have traditionally been used to differentiate and group species. The general assumption has been that modified species belong to one group and unmodified species to another. These two ‘species groups’ are subdivided into ‘subgroups’, but little effort has been made to resolve relationships among them. We conduct the first numerical cladistic analysis of Rheumatobates using a data set comprised of 102 characters, primarily describing modification of male external morphology. To address concerns about the inclusion of characters to be optimized on the phylogeny, characters describing modification of antennae and hind legs were included and then excluded in separate analyses. A preferred phylogeny was chosen from the four equally parsimonious cladograms found after successive reweighting of characters. There was good resolution at all levels of the phylogeny. Most of the major clades and terminal relationships were moderately to strongly supported, whereas the basal relationships were less well supported. The general assumption that unmodified and modified species form two monophyletic groups was not supported. However, traditionally recognized ‘subgroups’ within the modified species group were largely upheld. The analysis also suggested several major clades and relationships among these clades that were not previously recognized. The exclusion of characters describing modification of antennae and hind legs did not change the resolved major clades of the reconstructed phylogeny.

Simulium (Inaequalium) marins, a new species of black fly (Diptera: Simuliidae) from inselbergs in Brazil

A new species of black fly, Simulium (Inaequalium) marins (Diptera: Simuliidae), is described based on the male, female, pupa and larva. This new species was collected from two localities: a small stream on the Pico dos Marins, a high mountain with granite outcrops in Piquete County, state of São Paulo, and in a small stream in the Serra dos Orgãos National Park, state of Rio de Janeiro, Brazil.

Reassignment of Western Australia Paracnephia gladiator Moulton & Adler to a new genus, Bunyipellum (Diptera: Simuliidae)

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.

Taxonomic revision of Paraustrosimulium Wygodzinsky & Coscarón: reassignment of Austrosimulium colboi and description of P. obcidens n. sp. from Western Australia

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.

Precipitation and ectoparasitism reduce reproductive success in an arctic-nesting top-predator

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.