A preliminary assessment of
Subarctic black fly diversity (Diptera: Simuliidae) in Norman Wells and
environs, Northwest Territories
Douglas C. Currie
Department of Natural History, Royal Ontario Museum, 100 Queen’s Park,
Toronto, ON M5S 2C6 — firstname.lastname@example.org
The Biological Survey of Canada’s current Insects of the Arctic project was
initiated in 2000 to document entomological diversity in the vast and sparsely
surveyed territory between the Mackenzie River and Hudson Bay. Led by Donna
Giberson (University of Prince Edward Island) and Doug Currie (Royal Ontario
Museum), a total of 4 expeditions have been conducted at strategic localities
throughout the Canadian Central Barrens (Currie and Adler 2000, Currie et al.
2000, Currie et al. 2002, Giberson and Currie 2004, Giberson 2005). Although
emphasis has been placed on particular target groups of insects — in
particular the Ephemeroptera, Plecoptera, Trichoptera, aquatic Coleoptera, and
Diptera: Simuliidae — a common pattern has emerged: that current knowledge
about the diversity and distribution of Arctic insects is woefully inadequate.
For example, the 43 species of black flies (Simuliidae) collected during just
three expeditions nearly doubled the previous estimate for that family (22
species) for all of Arctic Canada east of the Mackenzie River. The current
database of Arctic black flies provides a much sounder base from which to
interpret biogeographical patterns.
A number of black fly species encountered during our Arctic
surveys are exceedingly rare, being represented in North America by just a
handful of collections. And one species in particular — Simulium (Schoenbauria)
giganteum — is currently known in North America from just a single
specimen collected near Arviat, Nunavut (Adler et al. 2004). Whether such
"Arctic" species are truly rare, or are more abundantly represented in
the Subarctic Ecoclimatic Region, is currently not known. Unfortunately, the
Subarctic zone of Canada remains largely unsurveyed due to lack of roads and
communities – the same problems that have traditionally plagued collecting
efforts in Arctic Canada. In this respect, the Subarctic Ecoclimatic Region
remains among the last frontiers of Canadian entomology. In this article I
reveal what insights can be gained from just a single, brief, collecting trip to
the Subarctic zone of the westernmost Northwest Territories.
Norman Wells and Logistics
Situated on the east bank of the Mackenzie River between the Mackenzie and
Franklin Mountains, the town of Norman Wells is a hub for oil drilling and
exploration in the western Northwest Territories. There is no road access except
for a winter road that that connects the community with Wrigley to the south.
For most visitors, access is available year-round by regularly scheduled flights
from Edmonton. Accommodations are rather limited with only 3 hotels and a Bed
and Breakfast listed for Norman Wells. It is recommended that you make your
reservations well in advance as rooms can become scarce during the summer. The
community has a small road network that extends for a short distance north and
south along the bank of the Mackenzie River; and a longer road that extends some
10 kilometers east to Jackfish Lake in the Franklin Mountains. A rudimentary
campground is situated at the terminus of the road, but its distance from Norman
Wells perhaps renders this option untenable for the long run. To explore the
region fully one must be prepared for backcountry travel, which requires either
the assistance of a licensed outfitter, or the support of local government
officials. I was fortunate enough to receive the latter through the generous
support of Alastair Veitch, a wildlife biologist with the Northwest Territories
Department of Environment and Natural Resources, Sahtu Region. In fact, it was
Alastair who contacted me after having found a previous Arctic Corner article by
me on the web. Although his main responsibility is to monitor wildlife
populations and health in the Sahtu Region, he maintains a keen interest in all
aspects of the ecology of the region. In fact, he has already started
collaborations with other entomologists including Ross Layberry (Lepidoptera)
and Paul Catling (Odonata). At his invitation I visited Norman Wells twice in
2005 to survey black flies: once in late May to set up a Malaise trap and to
collect immatures, and once again in late September to retrieve Malaise-trap
samples and to give a series of presentations to students at the Mackenzie
The Ecoclimatic Regions of Canada, with an inset map
of Norman Wells and environs. Abbreviations: A = Arctic; SA = Subarctic; B =
Boreal; B = Grassland; CT = Cool Temperate; MT = Moderate Temperate; C =
Cordilleran; IC = Interior Cordilleran; and PC = Pacific Cordilleran
Although my Spring visit to Norman Wells was relatively short (3 days), I was
able to maximize my collecting efforts by using various means of transportation.
I easily surveyed most of the local streams — the breeding sites of black
flies — by using a truck to navigate the drivable portions of the road
network. Equally effective was the use of a boat to ply the Mackenzie River. The
main channel was far too deep and swiftly flowing to make collections from the
river itself, but the boat made it possible to visit a variety of smaller-sized
tributaries at their confluence with the Mackenzie. Getting helicopter time was
fortuitous as I was able to take advantage of an empty seat on a
government-sponsored flight to the site of a fuel spill. The helicopter stopped
at several sites along the affected waterway, and I was able to make collections
of immature black flies at each stop. In addition to making collections of
immature black flies, I set a Malaise trap along the margin of the Mackenzie
River to capture adults of species that were inaccessible as larvae. A local
student was hired to monitor the trap and to change the head once a week from
late May until late September.
Sampling black fly larvae at the
outlet of Jackfish Lake. (D.C. Currie)
Results presented here pertain only to the Spring collections as the May -
September Malaise trap samples have yet to be analyzed. Eighteen collections of
immature black flies were taken over a 3-day period in Norman Wells and
vicinity. Morphological examination yielded 19 species or species-complexes
divided among 6 genera as follows: Helodon (1), Prosimulium (1), Greniera
(1), Stegopterna (1), Metacnephia (1), Simulium s.l. (14).
Although most of the species or species-complexes could reasonably be expected
in the Norman Wells area based on current knowledge of black fly distributions,
at least two records stand out. Simulium (Nevermannia) fionae
was previously known from New Brunswick to eastern Saskatchewan, south to
Michigan, Pennsylvania and New Jersey. Its presence in Norman Wells indicates
that S. fionae is much more widely distributed than previously supposed.
Equally remarkable was the discovery of Simulium (Psilozia)
argus, a species that was previously known to occur abundantly in western
North America from southern British Columbia to southern Mexico. That such a
widely distributed species could escape detection in the intensively surveyed
area between southern British Columbia and northern Northwest Territories seems
The Canadian Subarctic zone is so sparsely surveyed that even a short, 3-day,
collecting trip can provide dramatic new insights into the distribution and
diversity of northern black flies. It is intriguing to ponder what might be
revealed by a more intensive collecting effort, or by subjecting the known
sibling-species complexes to cytological scrutiny. It is clear that much work
remains to be done — not only in Norman Wells, but across the entire Subarctic
zone of Canada. The unsorted Malaise-trap samples will no doubt hold additional
surprises, and they will also provide valuable new insights about the phenology
and succession of large-river species of black flies. But the available
collections represent only a fraction of the potential simuliid fauna from the
western Northwest Territories. The Mackenzie Mountains, which rise directly
across the river from Norman Wells, have never been subjected to a rigorous
collecting program. This chain represents the easternmost boundary of Beringia,
and unquestionably supports Beringian endemics that have yet to be recorded from
the Northwest Territories. This fact alone is sufficient inducement to plan a
return visit to Norman Wells in the near future.
Thick layers of ice persist along
the banks of the Mackenzie River after spring break-up. (D.C. Currie)
Recent studies confirm that the rate of warming in the Arctic is twice the
global average. Profound, and perhaps irreversible, changes are beginning to be
documented as a change from arctic to subarctic conditions is underway, with a
concomitant shift of more temperate-adapted organisms to the north (e.g.,
Grebmeier et al. 2006; Sturm et al. 2001). Insects have unparalleled potential
to track ecological changes due to their reproductive capacity and sensitivity
to changes in temperature; however, the current state of knowledge is so
inadequate that it is difficult to assess what represents a ‘change’ and
what represents the status quo. Additional baseline data on the Subarctic
entomofauna are needed in order to track the changes that will inevitably
influence the Arctic landscape. Anyone interested in conducting entomological
research in the Norman Wells area is encouraged to contact Alasdair Veitch and
his colleagues in the Department of Environment and Natural Resources. Their
hospitality and generous assistance make any visit to the region worthwhile.
biologist Richard Popko checks the Malaise Trap that was set on east bank of the
Mackenzie River from late May through late September.
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