What’s in a name? A previously unrecognized species of North American black fly from Baffin Island

Biting flies are a scourge at northern latitudes. Nearly every early explorer made reference to the tenacity and voracity of these tiny insects. Not surprisingly, biting flies reach their peak abundances in northern environments, with mosquito densities reaching a staggering 12.5 million individuals per hectare in the Hudson Bay Lowlands. Similarly, black fly larvae can reach densities of 1.2 million per square meter of stream substrate under optimal conditions. Given their abundances, and economic importance (through blood feeding and transmission of parasitic diseases), it is not surprising that biting flies are among the best known insects in North America.

Black flies are an especially well known as they were the subject of a monumental revision of the North American simuliid fauna by Adler et al. (2004).  In fact, no new North American species have been described since that book was published 9 years ago. Consequently, I was amazed to discover a hitherto unknown species near Iqaluit, NU on southern Baffin Island (Figure 1). It is a member of the circumpolar genus Stegopterna (Enderlein 1930) which includes 8 North American species.  However, only one species — St. emergens (Stone 1952) — is known to be distributed widely at northern latitudes.

This previously unknown species was overlooked during initial sorting and counting. However, subsequent DNA barcoding, revealed >10% sequence divergence between this species and Stegopterna emergens, the species it was initially mistaken for. This prompted a closer examination of the morphology of the Iqaluit population, which differed from St. emergens in 2 important ways. The first relates to the length of the pupal gill trunk (Figure 2). Pupal gills are often used for species level identification of black flies, and this difference was consistent in all specimens examined. However, a more striking and ecologically significant difference is that the Iqaluit species has mouthparts adapted for blood feeding. Distributional records reveal that, of the 9 black fly species previously recorded from the Canadian Arctic Archipelago, only 2 had biting mouthparts. The other species were arctic-adapted (i.e., non-bloodsucking) species that use nutrients from their larval stages to develop their eggs. Interestingly, the two biting species were both found only on southernmost Baffin Island.

The discovery of this previously unknown species of bloodsucking black fly raises important ecological and evolutionary questions. Historical records suggest that St. emergens was present on southern Baffin Island during the 1950s; however, contemporary collections yielded only this previously unrecognized one. Were historically collected specimens simply mistaken for this undescribed species, or was St. emergens supplanted by this new one on southern Baffin Island? Reexamination of historically collected material in the Canadian National Collection of Insects is needed to select from these alternative hypotheses. DNA barcoding may again prove useful should the diagnostic life stages (i.e., adult females, pupae) prove unavailable for study.

Another important question is why southern Baffin Island was the only region in the Canadian Arctic Archipelago to historically support bloodsucking black flies. The recent discovery of yet another blood feeding species on the Island (Schaefer 2011) further reinforces the suitability of conditions for this feeding habit. A more favorable climatic regime seems a likely explanation; however, further analyses are required.

Finally, this undescribed species was not present at any other Arctic or Boreal site sampled by the NBP. This raises the question of how widely distributed this species is. There have been no records of morphological or chromosomal differences between mainland and continental island populations, nor have any continental island endemic black flies have ever been found in North America. This makes it extremely unlikely that this new species is restricted to Baffin Island and suggests its distribution likely extends southward into northern Quebec or westward across Nunavut (albeit in potentially low numbers).

The process of assigning a name to this previously unrecognized species is not particularly straightforward. While it’s possible that the southern Baffin Island Stegopterna is an undescribed (i.e., is a new to science) species, we can’t rule out the possibility that it’s actually a Holarctic species that already carries a valid scientific name.  Unfortunately, Stegopterna species are notoriously difficult to identify morphologically, and there are at least 7 candidate names to consider from the northern Palearctic Region (all members of the St. trigonium species complex). We must now begin the process of poring over species descriptions to determine whether any of the available names could reasonably be applied to the southern Baffin Island population. But however this exercise turns out, it’s gratifying to know that there are still new and exciting discoveries to be made in northern Canada.

References

Adler, P.H., D.C. Currie and D.M. Wood. 2004. The Black Flies (Simuliidae) of North America. Cornell University Press. Ithaca, NY.

Schaefer, P. 2011. Update on the biting fly component (Diptera: Simuliidae, Culicidae and Tabanidae) of the Northern Biodiversity Program. Newsletter of the Biological Society of Canada 30: 41-49.

“Mastering” northern flies: another student crosses the finish line

By Terry Wheeler (originally posted at http://lymanmuseum.wordpress.com/2013/06/08/mastering-northern-flies-another-student-crosses-the-finish-line/)

I’ve written previously about our work on the flies from the Northern Biodiversity Program (the joys of collecting them, and the challenge of processing them). Three years, tons of travel, a mind-boggling number of hours in the lab, and more than a hundred thousand specimens into the project, we are starting to see the first wave of student projects wrapped up. And it’s a great feeling.

I’m delighted to report that my M.Sc. student Meagan Blair has joined the list of NBP grad students who have finished their thesis. Meagan’s thesis on spatial patterns and long-term change in northern scathophagid flies has been awarded a Pass. So, huge congratulations to Meagan for successfully steering an ambitious project on a large and difficult group of flies through to completion. Meagan was part of the first wave of students who joined the NBP in the first year of sampling in 2010 and she was one of the few students who was in the field from start to finish in both the 2010 and 2011 field seasons. That’s a lot of northern time! Meagan was also one of the stalwarts in the NBP “sorting room” in the Lyman Museum, cleaning, sorting and processing vast amounts of material before she could start in on the long hours of microscope time needed to identify her flies.

Scathophagids, also known by the unflattering common name of “dung flies” are probably most familiar to many people through the big fuzzy yellow dung fly Scathophaga stercoraria, which seems to be fond of sitting on fresh piles of cow manure (hence the name). They don’t eat the manure though; they eat the insects that feed on the manure. But that yellow dung fly is only one member of this morphologically and ecologically diverse family of flies, a family that has some very sleek, colourful and, yes, very attractive species. Many scathophagids are predators, others are scavengers and many feed on live plants. They are also interesting from the perspective of our NBP project because they are one of the few families of flies (and indeed one of the few families of insects) that becomes more diverse as you move north into the arctic.

Meagan found high species richness and high abundance of scathophagids at our NBP sampling sites from the northern edge of the boreal forest right up to the high arctic islands. And there is a significant change in the species found from site to site. Our late colleague Dick Vockeroth had a great interest in northern Scathophagidae and in 1958 Dick proposed what some of us informally call “Vockeroth’s Rule”. Dick hypothesized that tree line is a strong filter for scathophagid distributions, with species found either north of, or south of, tree line, but not both. Meagan’s work added several species to Vockeroth’s initial data set from his 1958 paper and in most cases confirmed that strong split at tree line (although what it is about tree line that actually limits the distribution of generalist scavengers and predators is another question).

Meagan’s work on documenting the current patterns of distribution of northern scathophagids will provide a valuable starting point for tracking change in distributions in the future as climate change causes the north to warm up. Will these flies track tree line north, or will a more complex set of interactions drive future patterns? Will the species that are dominant now remain dominant at the same sites into the future?

Meagan also reached back into time to compare our NBP specimens to specimens of the same species collected at the same sites in the early 1950′s. Her question was simple: “have northern flies themselves changed over the past half-century?”. The answer was “yes”, and in an interesting way. It’s not just the composition of the insect communities that are being affected by a changing north, there are evolutionary changes in the species themselves.

I won’t give away any more details of Meagan’s results here. A finished thesis is a very satisfying milestone along the academic journey, but it’s the published papers that matter most — those are the products that are read by the broader scientific community. We’re working on those now and you’ll be hearing more about Meagan’s results in the future.

The joys of arctic fieldwork: Meagan hunting flies on Ellesmere Island (photo: Donna Giberson)

The joys of arctic fieldwork: Meagan hunting flies on Ellesmere Island (photo: Donna Giberson)

 

It’s a wrap! How about a thesis on Arctic spiders? How about two of them…?

By Dr. Christopher Buddle

This week I am thrilled to report that two of my MSc students have successfully completed their degrees! Both the projects are part of the collaborative Northern Biodiversity Program – a project aimed to quantify and understand ecological change with Arthropods from Canada’s north.

A BIG congratulations to Sarah Loboda and Katie Sim  – they are both tremendously talented students, excellent Arachnologists, and wonderful people to know.  Last night we had our annual Lab BBQ – and at that event, I was pleased to give Sarah and Katie a small token of appreciation.  Here’s a photo showing them both with their wolf spider photographs (photos by the incredible Thomas Shahan):

Katie Sim (l) and Sarah Loboda (r) - successful MSc students!

Katie Sim (left) and Sarah Loboda (right) – successful (& happy) MSc students!

Sarah Loboda’s thesis is titled Multi-scale patterns of ground-dwelling spider (Araneae) diversity in northern Canada. Her research focused on broad diversity patterns of ground-dwelling spiders collected from our 12 study sites, spread across Canada’s north. Our project spanned 30 degrees of latitude and 80 degrees of longitude –> yes that is a lot of land area! Sarah identified over 300 spider species from 14 families, and over 23,000 individuals.  Publications are forthcoming so I won’t give details here, except to say that we can learn a lot about diversity patterns over broad spatial scales using a study taxon such as spiders.

Here's where the Northern Biodiversity Program took our field teams!

Here’s where the Northern Biodiversity Program took our field teams.

Katie’s work (co-supervised by Prof. Terry Wheeler) had a different slant, but was still on Arctic spiders. Her thesis is titled:  Genetic analysis of Pardosa wolf spiders (Araneae: Lycosidae) across the northern Nearctic. The first part of Katie’s thesis was about understanding the phylogeographic history of the Arctic spider Pardosa glacialis, with particular attention to post-glacial dispersal patterns, as inferred by population genetics. The second part of her thesis was focused on whether or not there is enough evidence to suggest two northern Pardosa species should remain as separate species, or be merged into one – based on both molecular and morphological characters.  Let’s just say that Katie had to be a ‘field genius‘, ‘lab genius‘ and ‘spider genitalia genius‘.  Here’s an example of what she looked at, a lot:

The epigynum of a wolf spider species, (part of) the topic of Katie's research.

The epigynum of a wolf spider species, (part of) the topic of Katie’s research.

In sum, I am thrilled to see Sarah and Katie finish up their work, although their success also comes with a touch of sadness, as I will miss their daily presence in the laboratory.  Stay tuned… we shall soon report all the details from their research.

Assessing five decades of change in a high Arctic parasitoid community

By Christopher Buddle

As my colleague Terry Wheeler mentioned on his blog, our Northern Biodiversity Program team is thrilled to see post-doc Laura Timms‘s paper about Arctic parasitoid wasps published in Ecography!  Our team worked on Ellesmere Island, Nunavut, in 2010, and compared parasitoid wasps to historical collections from the same site that were made in 1961-65, 1980-82, and 1989-92. Parasitoid wasps are at the top of the insect food chain: they lay eggs inside or on top of other arthropods and the wasp larvae emerge after consuming their hosts – a gruesome but very common lifestyle for many types of wasps.  Species at higher trophic levels, such as these parasitoid wasps, are often the first to respond to new environmental pressures, including the climate change that is occurring rapidly in Arctic systems.

Some members of the Northern Biodiversity Program working in the Yukon in 2012. (l-r, Chris Buddle, Laura Timms, Crystal Ernst and Katie Sim)

Some members of the Northern Biodiversity Program working in the Yukon in 2012. (l-r, Chris Buddle, Laura Timms, Crystal Ernst and Katie Sim)

Laura identified a LOT of wasps, recorded the type of host attacked (e.g. plant-feeding hosts versus hosts that are predators), and the body size of two species of wasps that were commonly collected in all time periods.  We found no clear pattern of change in most aspects of the parasitoid wasp community on Ellesmere Island over past 50 years, even though temperature and precipitation have increased significantly during the same period. However, there were some signs that parasitoids of plant-feeding insects may be more affected more than other groups: one common parasitoid species that was abundant in 1960s hasn’t been collected since then, and the community in the 2010 study contained fewer parasitoids of plant-feeding insects than previous studies.

Laura takes it as a good sign that no major changes in the ecology of the high Arctic parasitoid community have been observed, but isn’t taking it for granted that the community will remain unaffected for long.  At 82°N, Ellesmere Island is relatively isolated, but other research has found that parasitoid communities further south are changing dramatically (Fernandez-Triana et al 2011).

Laura has the following comment about our work: “We hope that our findings will be used as baseline data for ongoing monitoring on Ellesmere Island”, said Timms.  “We know so little about these high Arctic insect communities, we should learn as much as possible about them while they are still intact.

References

Timms, L., Bennett, A., Buddle, C., & Wheeler, T. (2013). Assessing five decades of change in a high Arctic parasitoid community Ecography DOI: 10.1111/j.1600-0587.2012.00278.x

Fernandez-Triana, J., Smith, M., Boudreault, C., Goulet, H., Hebert, P., Smith, A., & Roughley, R. (2011). A Poorly Known High-Latitude Parasitoid Wasp Community: Unexpected Diversity and Dramatic Changes through Time PLoS ONE, 6 (8) DOI:10.1371/journal.pone.0023719

The NBP “YouTubes its entomology”

Every year, the Entomological Society of America holds a YouTube Your Entomology contest in association with its annual meeting. This year, NBP team member Sarah Loboda submitted a video that she created after her 2010 field season in Schefferville, QC. It’s been featured on this blog before, but it warrants another viewing (it’s just that awesome!) We may be biased, but we’re pretty sure this is a winning entry. Good luck, Sarah!

Successful pseudoscorpion hunting in the Yukon

By Chris Buddle, McGill University

The Arctic Pseudoscorpion Wyochernes asiaticus

I am heading back home after a simply amazing field trip to the Yukon Territory. As mentioned in a previous post, one of the goals of the trip was to collect more specimens of an Arctic pseudoscorpion Wyochernes asiaticus (Family Chernetidae) – a Beringian species known from Siberia, Tibet, and the Yukon. This species survived the last great glaciation event in North America by living in unglaciated regions of the northwest, including parts of the Yukon. In 2008 I had collected this species under rocks beside high elevation and high latitude creeks and rivers in a few locations in the Yukon. On this trip, my goal was to collect more specimens to further assess the distribution of this Beringian species, and to gather more life-history information including estimates of size and fecundity. Because of the relative rarity of pseudoscorpions, few data exist that describe life-history parameters of these arachnids.

Despite some rather wet and cold weather for a lot of the trip, the pseudoscorpion collecting was completely successful – we were able to collect hundreds of specimens, from the south end of the Dempster Highway (approximate latitude 64.3 degrees N) all the way up into the Northwest Territories (>67 degrees N). We collected specimens under rocks in more boreal regions, as well as the upper headwaters of high elevation creeks – some of these less than a metre wide. Here is an example of one of these northern, high elevation creeks in the Northwest Territories, just beyond the Yukon-NWT border:

An Arctic, high-elevation stream in the Northwest Territories: pseudoscorprion country!

To give you some idea of the ease of collecting, here is an example of what you might find when flipping over rocks beside the creeks:

Several Wyochernes asiaticus (Pseudoscorpiones) females (with yellow eggs visible)

I was also able to capture some video of these pseudoscorpions – as far as I am aware, Wyochernes has never before been videotaped, so this is the FIRST EVER movie of this species!

Our larger research goals included more than pseudoscorpion colleting, and I was in the Yukon with a wonderful team of scientists, including my graduate students Crystal Ernst, Katie Sim, a post-doctoral researcher Dr. Laura Timms, and an entomology professor from the University of Manitoba, Dr. Barb Sharanowski. We all had different objectives and goals for the Yukon trip, and over the next couple of weeks. I will post some more research stories from this field-work to give a sense of the scope of our research efforts in the Yukon.

The research team at the Arctic circle (Laura, Katie, Crystal, Barb & Chris)

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Originally posted at Dr. Buddle’s Arthropod Ecology blog, here: http://arthropodecology.com/2012/07/19/successful-pseudoscorpion-hunting-in-the-yukon/

Help Build an Arctic Food Web

Posted on behalf of Dr. Chris Buddle (the original post can be found here, at the Arthropod Ecology blog)
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A couple of weeks ago I was fortunate to be able to attend a workshop about monitoring terrestrial arthropod biodiversity in the Arctic. In advance of that workshop, I offered to prepare a draft of a food-web that was ‘Arthropod-centric’.  There are many ways to build a food-web, and my first draft was focused on who eats whom.  In other words, an arrow depicting interactions would indicate predation (loosely defined).  An alternative would be to focus on energy moving through the system (i.e., the arrow would move ‘up’ from trophic level to trophic level, to indicate a transfer of energy).

Putting this together is a challenging, yet rewarding process.   I consulted with many of my colleagues with expertise in Arctic systems (including the folks involved with our Northern Biodiversity Program), and I am struggling to find the right balance between generality and specificity.  Here’s a portion of the (draft) food-web, showing some of the interactions:

Part of an Arctic Food Web, with an Arthropod Focus

When working on this food web, some interesting generalities are emerging: First, the overall dominance of Diptera (flies).  This is certainly because they do everything (e.g., decomposers, pollinators, blood-feeders) and they are very diverse.   Second,  arthropods are integrators - meaning they connect different processes, and they bridge different systems (aquatic/terrestrial).  Third,  highly valued vertebrates  (and humans!) depend on arthropods (and/or are affected by them).

Does all of this pique your interest?  Want to help? Together with colleagues, I am seeking help as this food-web develops.  Send me an e-mail (chris.buddle@mcgill.ca) or drop a comment on this post and think about some of these questions and provide some feedback if you are so inclined:

….what interactions do you think are important in the Arctic, from an arthropod perspective?

….how can the interactions between vertebrates and invertebrates best be depicted?

….what interactions between humans and arthropods need to be included? (other than biting flies – that one is pretty obvious!)

….what ecological processes should be included in an Arctic food-web? 

There are other Arctic food-webs out there.   The Bear Island food-web is probably the best one that focuses on Arctic arthropods.  If you’ve not seen it, the paper by Ian Hodkinson and Stephen Coulson (2004) is worth a look.   That food-web is more specific than the one I am working on (it should be since it’s focused on a specific location and it can be because a lot of research has occurred there!).   I really like one of the last sentences in their paper: ...the Svalbard high Arctic terrestrial food web is far more complex than has previously been appreciated but further sections remain to be resolved.  Indeed!  I would argue that we need to develop these kind of specific food-webs from other locations in the Arctic, but to get there, we also need a general, broad overview that encapsulates the overall role and importance of Arthropods to the Arctic.  Hence the development of a general food web.

I’ll finish with some thoughts about using this blog as a platform for generating and refining ideas about this food web.  Last year I had a long discussion with my PhD student Crystal Ernst (aka the Bug Geek) about the use of social media in the creative thinking process.   Some parts of the discussion we had showed up in one of her posts about the role of social media in science.  There’s a nice quote in that post that really hits the nail on the head:

Social media is just another kind of “hallway talk…in a really, really, long hallway”. (Crystal attributes part of that quote to another fine blogger, Bug Girl)

Social media can be used effectively as a platform for soliciting feedback and generating ideas about science, including specific projects such as building a food-web diagram.   At this stage, I admit that I’m not ready to put the entire draft food-web in this post – it’s far too incomplete.  However, it is the perfect time to ask for help, and solicit ideas.

….I welcome your feedback.