What makes a good collecting trip good?

“Have a good trip! How’s the trip going? How was the trip?” These are things people say to me before, during, and after fieldwork trips. I go into the field to collect insects. I do this because that’s where a lot of my research data comes from. So, over the past couple of days, as I wind up my sixth summer of arctic fieldwork, I’ve been thinking that all my answers to all those questions are always “good” (or some superlative flavour of good, usually something along the lines of “great” or “11 out of 10” or “I’m not coming home”).

But yesterday as I was driving south from Dawson City bound for Whitehorse, I was thinking about what does make a good collecting trip good, and I realized that, for me at least, it’s the conjunction of many little pieces. So here, without further preamble or disclaimer, and in no particular order except for the first one, is my list of some of the things that make a good collecting trip good for me.

• We collect surprising insects in places I didn’t expect to find them (good collecting is, after all, the main purpose of doing this fieldwork in the first place!)

• Replicated samples are successfully gathered in numbers suitable for the appropriate analyses.

• None of the collecting nets or traps are destroyed by bears, muskox, dogs, ravens, rose bushes, falling trees, off-road vehicles, or other non-demonic intrusions (except where we have brought extras of the low-cost ones, thereby making me seem like a brilliant planner).

• Neither the first-aid kit nor the bear spray are used.

• On the Opening Grocery Expedition, we buy enough food, but not too much food. And everybody has a say in, and agrees on, what food we buy.

• The food is good and healthy and fresh and never so repetitive that rumours of mutiny are heard.

• The music we bring is good and varied and never so repetitive that rumours of mutiny are heard.

• Everybody works hard, but not so hard that we miss out on chances to explore natural history, cultural history and the sheer joy of being in a special place.

• All the field guides we bring are used, but we don’t regret not having any that we didn’t bring.

• I learn some new things about the natural history or cultural history of the place that I didn’t know before the trip.

• We meet interesting people along the road. All sorts of people. Some are curious about our work and want to know more.

• Nobody bickers with anybody else. But if we do, it is defused quickly, then we’re all OK again.

• Nobody is the Big Boss, and nobody is an underling. We’re a Team.

• There is ice cream.

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Lines on a map. Dots on a map.

I’m crossing some lines in the Yukon. I’m searching for dots.

Several lines drawn on maps define the Yukon for me. There’s a straight line across the bottom of the Territory that marks 60° north latitude. To many Canadians, “north” is what’s beyond that line. It’s a line mostly drawn by politicians and mapmakers, but it’s also a line that defines the way people view part of this giant country. In Canada, “North” is a thing.

Farther north, up at latitude 66°33’ there’s another straight line – the Arctic Circle. That one goes right around the planet. It’s a line drawn by astronomy. At that line, the sun doesn’t set on the longest day of the year, and it doesn’t rise on the shortest.

Between those two, there’s a squiggly, fuzzy line running more or less east and west. It’s the tree line. It’s a line drawn by biology and geology and climate. South of tree line there’s forest; north of tree line there’s tundra. But like most things biological, it’s not quite that simple. When you zoom in far beyond the level of that giant map of Canada on the wall, things get messy because tree line is spotty and broken and moving, depending on the interactions of living and non-living things. Patches of trees come and go up here. It’s like they didn’t even bother to look at the map at all.

Windy Pass, Yukon. Up on the edge of Beringia.

Windy Pass, Yukon. Up on the edge of Beringia (photo: T.A. Wheeler).

The fourth line, the one I’m tracing instead of crossing, is the Dempster Highway – a 732 kilometer, two-lane (more or less) ribbon of gravel running north (more or less) from near Dawson City, up through forests and tundra and then some more forest and then tundra, across the Arctic Circle, across northern rivers, to Inuvik, up on the huge Mackenzie Delta near the Arctic Ocean. It’s a line drawn by road-building crews and the native guides who showed them the best route. It follows old winding paths and carves new straight lines. In some of the straight stretches, the road is also an airstrip (don’t stop there). It winds along rivers, over low mountain passes, and rides on top of a thick bed of rock and gravel laid down over the permafrost. I drive up and down this road looking for dots to add to a map.

Dempster Highway, near North Fork Pass. The road to discovery (photo: T.A. Wheeler).

Dempster Highway, near North Fork Pass. The road to discovery (photo: T.A. Wheeler).

I’ve been collecting insects along the Dempster almost every year since 2011. Each year our research questions are a little different, our field crews are a little different, our focus is a little different. This year I’m mostly focused on collecting data for a long-standing project in taxonomy (where the root question is “what is this thing?”) and faunistics (where the root question is “what things are here?”). My main group of interest is the fly family Chloropidae. It’s a diverse and abundant group of little flies that live everywhere from tropical rainforest canopies to deserts to urban backyards to the high arctic tundra. And they play a huge range of ecological roles, from herbivores to scavengers to predators to parasites to pollinators. On my first visit to the southern Yukon in 1997 I started collecting chloropids and I soon noticed how many species there were, how widespread they were, and how many seemed to be undescribed species, or species unrecorded in North America.

That last part – unrecorded in North America – is especially relevant to research in the Yukon, because this part of the continent is a crossroads for species. Many widespread North American species range all the way up through Yukon and Alaska, but this place is also special because when most of Canada was covered with ice for much of the past two million years, a big chunk of Yukon and Alaska were ice-free, part of the great Beringian refugium. Beringia was a gateway for many species to walk or crawl or swim or be carried by wind or animals or water from eastern Russia into North America. And many of them stayed up here. So we know of several species that are widespread through Eurasia but only found in North America way up here in the northwest corner. Because of the glaciers. But, the species we know are only a small fraction of the species that are probably up here, especially in poorly studied groups like insects and other small invertebrates.

So I’ve been travelling the Yukon, stopping along the accessible routes to put out insect traps and sweep the vegetation for flies. And in most places I collect, there are chloropid flies. When I get back to the lab and prepare the specimens, I can identify the species, find out whether they are named or not, and I can put another little dot on a big map that says “this species lives here”. My dots come from my own collecting in the field, but also from samples collected by colleagues, and also from the rich holdings of older specimens housed in natural history museums. All the dots together give us a picture of the diversity of this one family of small flies up here, and when I’m done I’ll have produced a piece of work called The Chloropidae of The Yukon (or something like that; still a working title), that will help us understand a little piece of the biodiversity of this place a little better. And my dots can be combined with other dots of other groups drawn by other researchers, to help draw a very detailed pattern of dots.

So who cares? What’s the use of those dots? Well, those dots drawn by taxonomy and faunistic work are the basis for a whole suite of questions in ecology and biodiversity and conservation. With enough dots, we can define the structure of ecological communities, we can map them onto biotic and abiotic gradients, we can monitor the change in what, and where, those dots are over short time periods (as habitats change) or over long time periods (as the biota of the north has changed during and after ice ages).

And who doesn’t like connecting the dots?

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Why the Yukon? My love of northern entomology

I’m north of 60° again. Back in Whitehorse, Yukon for the fourth time in five years, and getting ready to head north. Beyond Dawson City, beyond the trees, up the Dempster Highway to the tundra. I’m going to collect insects. Again. Many of my entomological colleagues and friends head for the tropics when they want to collect insects, especially unknown new species. I can see the appeal — I’ve collected in Jamaica, in Costa Rica, in the Australian tropics. I’ve found wonderful new things in all those places. So why do I keep coming back to places with more mosquitoes than trees? to places with permanently frozen ground? to places where predictions of latitudinal species diversity gradients say “meh, why bother?”

You are here. And great things await around the bend (photo: T.A. Wheeler)

You are here. And great things await around the bend (photo: T.A. Wheeler)

Because this is a magical place to do entomology. There are tons of discoveries to be made here whether you’re a taxonomist (which I am), an ecologist (which I am), or if you have an interest in the long-term history of the continent (which I do).

A big chunk of the Yukon Territory was part of what’s now known as Beringia — a vast swath of northeastern Russia, Alaska, Yukon, and dry seabed connecting them — that was mostly ice-free when the rest of Canada was covered by Pleistocene glaciers through long spans of the past two million years. Beringia was named by Eric Hultén, a Swedish botanist who recognized the unique composition of the plants of the region. But there’s much more that’s unique about Beringia than just plants. This region supported enormous populations of giant ice age mammals: mammoths and mastodons, ground sloths and giant beavers, short-faced bears, scimitar cats, horses, camels, saiga antelopes, and more. The bones of these creatures wash out of riverbanks all through the region. And they help us reconstruct the history of this place. Other evidence from the past tells us that the first Americans walked into North America through Beringia, and there are signs of their hunting on the old bones, and their stories talk about the giant mammals of the past.

There were insects in Beringia, just as there are insects everywhere, but there has been surprisingly little research done on many groups of Beringian insects. But they’re just as much part of the story of this place as mammoths and sedges and shrubs. And unlike the Pleistocene megafauna, many of the Beringian insects are probably still alive. That means that the footprint of glaciation is still there in their genes, in the distribution of species in this part of the continent, and in the structure of their communities. There’s a rich source of taxonomic, ecological, and genetic questions up here.

Taxonomic questions: Some groups of Beringian insects have been well-documented. There’s been a long interest in fossil beetles here, for example. And some excellent work has been done on butterflies and moths over the years. The Biological Survey of Canada published “Insects of The Yukon” in 1997, with chapters covering many families of Yukon insects and arachnids. But that 1000-page book still only scratched the surface. In our ongoing research on Yukon flies since 1997 we’ve discovered many new species up here. People are often surprised at how few of Canada’s insects are known or named, but it’s simple math: this is a huge and diverse country, with many thousands of insect species, and not nearly enough people describing our own native fauna. I don’t need to go to the tropical rainforest to discover new species; I just have to drive up the Klondike Highway or Dempster Highway and pull off the side of the road. One of the main objectives of my fieldwork here in the Yukon this summer is to collect specimens of some fly families in which we know there are several undescribed species. The additional material I hope to collect will help us document size and colour variation in these species, as well as filling out our knowledge of their geographic distribution. It’s important to put names on these new species because this species diversity is the foundation for other questions about northern biodiversity.

Ecological questions. Beringia was not only ice-free, there was also a surprsing range of habitat types here, from dry tundra to wetlands to shrubland to extensive grasslands. We know this from ancient plant remains — pollen and plant fossils from ice age deposits. And a wide variety of habitats means that more insect species can be supported because they often have a strong preference for particular habitats. In our fieldwork here the past few years we’ve been surprised to see how many more species in a range of fly families live in Beringia, compared to other northern regions that were glaciated. Research by several students in our lab: Stéphanie Boucher, Meagan Blair, Sabrina Rochefort, Élodie Vajda, and Anna Solecki, has identified much higher numbers of species than we would have expected. So some of the questions we’re now addressing are focused on how these rich communities of species co-exist in what otherwise looks like a harsh place. Of course, climate change continues to leave a mark on the north, so we’re also interested in the ongoing impacts of a warmer, wetter north on insect populations and communities.

Genetic questions. Beringia is a crossroads for insect species. Many of the native northern species probably survived the Pleistocene ice ages right here. But during peak periods of glaciation, insects from eastern Russia could fly or walk or crawl across the exposed bottom of the Bering Strait. This is why there are some species of widespread Eurasian species that also occur in Alaska and the Yukon. But since the end of glaciation, other southern species have moved northward, following suitable habitats northward into Beringia. So the communities of insects in some of these habitats are an interesting blend of insects from many places. The challenge is that we can’t always reconstruct that history just by identifying the species, because many are geographically widespread. So we have to delve into their DNA, where small changes and differences can be more obvious, and can tell us about recent movements and connections and divisions over the past several thousand years. This “phylogeographic” approach can give us a clearer picture of which species survived where, and how and when they’ve moved since the end of glaciation. Recently graduated student Anna Solecki has been exploring some of these patterns in northern flies and we’re hoping to keep exploring similar questions over the next few years.

From a distance, the north may look two-dimensional and uniform. To an entomologist, getting down to a fly-level view of things, this world is anything but! There are mysteries and questions here to keep me busy and excited for years to come.

So much still to discover. Tombstone Mountains, Yukon (photo: T.A. Wheeler)

So much still to discover. Tombstone Mountains, Yukon (photo: T.A. Wheeler)

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Taxonomy matters. Here’s why.

March 19th is Taxonomist Appreciation Day. I don’t think any government has made official pronouncements on that. That’s OK, we’ve got something better — social media. Taxonomist Appreciation Day was the brainchild of Terry McGlynn, an ecologist who understands the critical role that good taxonomy plays in, for example, understanding the ecology of tropical ants. In fact, taxonomy matters in many ways. The problem is that a lot of people, both inside and outside biology, don’t always realize how fundamental taxonomy is to the rest of biology.

Taxonomist Appreciation Day is a chance for people who don’t necessarily interact with taxonomists on a daily basis to say “hey, thanks”. But what are people thanking taxonomists for? What do taxonomists DO?

We discover new species and give them names. When we do that, we’re describing a little tiny piece of the diversity of life on earth, and taking a tiny step closer to understanding the planet.

We build the classifications that are the filing system to organize the diversity of life on earth. That filing system of genera and families and orders and the rest is the big information retrieval system that connects scientists and non-scientists to all the information about species.

We construct keys and field guides and other identification tools to allow non-taxonomists to identify species. These identification tools are the most direct way that we translate and transmit taxonomic knowledge to non-specialists. So, when you identify species using a key or a molecular library, although you’re not actually doing taxonomy, you’re using tools created by taxonomists (you’re welcome. It was our pleasure). And when those keys are really good and clear and smooth, it’s sometimes easy to forget the enormous amount of training, experience and hard work that went into producing that key.

We reconstruct phylogenetic relationships of species and higher taxa to produce hypotheses about shared evolutionary history. And those patterns of relationships form the basis for all sorts of other hypotheses in evolution and ecology. That’s because everything about species evolves. When we build a phylogenetic tree based on characteristics of the species, we’re building a picture of history, not just the history of those characters, but of their ecology, species associations, behavior, physiology, geographic distribution and other traits as well. That’s a powerful framework for interpreting patterns.

We build, organize and maintain the collections in natural history museums. We maintain the irreplaceable libraries of life, the place you can go to verify the identity of species, or to access other information about those specimens. We make the enormous resources represented by specimens available and accessible to other researchers.

That’s what taxonomists do. That’s why our work matters.

So, when we say “Thanks” to a taxonomist, it can be for any of a number of things:

“Thanks for putting a name on that new species so I can Google it”

“Thanks for publishing some photos and drawings so I know what that species looks like”

“Thanks for writing a decent key so I can identify these species from my research project”

“Thanks for identifying those mystery specimens that didn’t key out at all”

“Thanks for building that phylogenetic tree, so I know what this species is related to, and so I can plug in these functional traits and get some predictive power”

“Thanks for those natural history observations about habitat, behavior and food that you put in your taxonomic paper”

“Thanks for putting those specimens you collected in the museum. I’ll be able to [measure them/extract their DNA/look for chemical signatures/check their geographic range] soon for this other thing I’m working on”


Taxonomy is not “done”. There are millions of species still to describe and many more still to slot into their place on the tree of life. And not just in the wild places of the tropics. Here, in our back yards, in our parks, in our cities.

Taxonomy is not “old-fashioned”. Our tools and techniques evolve just as quickly as the tools of physics and medicine and molecular biology (heck, they’re some of the same tools), and allow us to explore new levels of complexity in the organisms we study. Some of our methods are timeless, and some are at the cutting edge of science. They all work. Really well.

Taxonomy is not the occasional new species of bug named after a celebrity. For every celebrity species name that makes a splash in the media, hundreds more appear in the primary scientific literature. Those names, derived from characteristics of the species, or the place they live, or their habits, or the person who collected the specimen,  may not be as entertaining, but they’re just as meaningful and the species are just as important. Taxonomists describe thousands of species every year. We’re busy.

Taxonomy is not an isolated pursuit. At least it shouldn’t be. Given the connections between taxonomy and the rest of biology, we have tons of opportunities to collaborate, to interact, to advise, to contribute.

I became a taxonomist because of my interactions with some great professors in my undergrad courses who did taxonomy; people like Dave Larson, who liked water beetles, and Bill Threlfall, who worked on parasites (and birds). I did both my graduate degrees in taxonomy: a M.Sc. with Mary Beverley-Burton, who taught me a lot about parasitic flatworms; and a PhD with Steve Marshall, whose infectious excitement about flies made me excited about flies. A couple of decades on, I work with a great group of undergrad and grad students doing taxonomy in the lab now. They help keep me excited about flies. About discovery. About the little thrill of being the first person to put a name on another tiny twig on the big tree of life.

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How many people does it take to describe a new species?

The Myth of the Solitary Taxonomist goes a bit like this: Solitary Taxonomist goes away to an exotic place, usually with at least one hazard to life and limb, usually land leeches. Collects a specimen. Recognizes it immediately as a new species. Comes home, writes a Solitary Paper describing the new species. Yes, it happens that way sometimes. But mostly it doesn’t.

In my previous post I talked about our latest paper from the lab in which grad student Sabrina Rochefort and I described a new species of fly that we called Parapiophila kugluktuk. That’s two taxonomists, for those keeping score. But, a lot more work and effort, by a lot more people, went into getting those specimens under Sabrina’s microscope so she could recognize those flies as something unusual and unknown. In a series of posts a couple of years ago I talked about the steps we go through to get insect samples from the field to the pin, and from specimen sorting to data analysis. But I want to talk a little bit about the back story of this particular new species. So, in the interest of showing that science is rarely a really solitary pursuit, and that there are almost always more people who deserve credit than the people who wrote the paper, in this post I’ll talk about the past events that intersected to get those flies into our hands.

Sometime late in 2008, four of us (Chris Buddle, Doug Currie, Donna Giberson and I) launched a plan to see if we could get a research grant to go north and study arctic arthropods in a changing north. Arctic fieldwork is expensive, and complicated, so in addition to applying to NSERC (the main funding agency), we also had to assemble a big list of partners, collaborators and other supporters, both in the north, and here in the south. In the end, the huge amount of work was worth it, because we got the grant.

Most of that money was going to go into fieldwork (flights, rental vehicles, fuel, food to keep the field teams healthy and happy) and salaries (not just for our postdoc and grad students, but undergrad lab and field assistants, northern field assistants, bear monitors, guides) and arranging the travel and housing (or tenting!) for all those people each year was a big job.

The project was mainly ecological, which means we had to design, set up and service standardized sampling grids in each of our 12 sites, from James Bay to the northern end of Ellesmere Island. But one of the side benefits of a well-designed ecology project is that the sampling also provides tons of great material for taxonomic work as well. In most of our sites we sampled for two weeks per year to catch the peak of insect activity, but in Kugluktuk, Nunavut, grad student Crystal Ernst needed a full season’s data. So with some great field assistance from local people like Angut Pedersen, Kenneth Kuodluak and others, the Kugluktuk team collected for the whole, brief, arctic summer.

Of course, all these bulk samples had to be sorted, so there was another few months work back in the lab to separate the flies, beetles, spiders, wasps, etc. Students like Meagan Blair, Sarah Loboda, Katie Sim and Anna Solecki put in many long days doing this critical work. After all the sorting, cleaning, drying, pinning, labelling, and more sorting, we finally reached a point where Sabrina could take the trays labelled “Piophilidae”, look at those flies from Kugluktuk, and finally decide “this looks weird”.

But Sabrina’s insight was only possible because previous generations of taxonomists had described and illustrated species and written identification keys. And those taxonomists were often keen collectors who themselves deposited specimens in natural history museums. We described Parapiophila kugluktuk from almost 200 specimens, but only 33 of them came from Crystal’s Kugluktuk samples. Others came from our other northern sampling sites in 2010–2011, but many of the specimens had been sitting unidentified in museum collections for decades, waiting for an expert to take a good look at them.

The old Northern Insect Survey had collectors busy across northern Canada for 15 years starting in the late 1940s, and some of Canada’s great Diptera specialists: Jim Chillcott, Frank McAlpine, Guy Shewell, Dick Vockeroth and Monty Wood all collected at least one specimen of this new species and got them into the National Collection in Ottawa. Other specimens came from the efforts of beetle or wasp or moth experts who collected broadly and made the material available. All these efforts from decades ago let us expand the known range of Parapiophila kugluktuk beyond our own sampling sites and across northern North America and down the Rocky Mountains.

But this new species isn’t just restricted to North America. We also have specimens from Abisko in northern Sweden. Some of these were collected back in 1951 by Dick Vockeroth from Ottawa, who had just finished his Ph.D. But the rest of the Swedish material was collected in 2001 by Jade Savage, who was my PhD student at the time. During her Ph.D. program Jade went to Sweden to collect flies in a different family, the Muscidae, but brought back many more samples to the lab to be processed and labelled and sorted. And they’ve been sitting in a Piophilidae drawer, in a fly cabinet, in the museum down the hall from my office ever since. Until Sabrina revisited them.

So yes, two of us wrote that paper and described that new species, but only after many years work by grant writers, supervisors, postdocs, grad students, undergrad students, field assistants, guides, bear monitors, bush pilots, northern partners, collectors and curators came together across the decades and across institutions to drop those weird little flies on our desks.

When you think about it, even “solitary science” still takes a village.

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High fliers: a new paper on some new arctic flies

Many people see the arctic as a pretty barren place, with not much biological diversity. In fact, one of the most well-known patterns in ecology — the latitudinal diversity gradient — incorporates that idea. As you leave the tropics and head north, species diversity drops. Apparently, the flies didn’t get the memo. There are lots of flies in the north. Lots. In fact, some groups of flies are so successful at living in the north that they defy the latitudinal diversity gradient and are much more diverse in the far north than in warm temperate or tropical regions. Lyman M.Sc. student Sabrina Rochefort and I have just published a new paper on one of those families, the skipper flies, or Piophilidae.

In our research with the Northern Biodiversity Program, we collected arthropods at 12 sites across northern Canada from treeline to the northern tip of Ellesmere Island. And flies were the most abundant group of arthropods at those sites, especially in the north. So far we’ve processed more than 100,000 flies representing a few hundred species of flies from our sites. And early on in the project, Sabrina, who was an undergrad student at the time, adopted the little family Piophilidae. Nobody had really worked on the family in North America since Frank McAlpine, another Canadian fly worker, published a taxonomic overview of the family in the 1970s, so they were ripe for some new attention.

Sabrina’s first task was to identify the species we had from our northern collections. Fortunately, most of the specimens that McAlpine had studied, including northern material collected a half-century ago by the Northern Insect Survey, were two hours up the road at the Canadian National Collection of Insects in Ottawa. Sabrina sorted out the material, putting names on the known species, and flagging the weird things for a closer look. As often happens in taxonomy, that closer look turned up some new discoveries.

The first discovery was a fly that Sabrina recognized early on as a new species. The first specimens she recognized were collected at Kugluktuk, Nunavut, a small hamlet near the mouth of the Coppermine River, where NBP grad student Crystal Ernst spent the summer collecting in 2010. Soon, we started finding more specimens of this new species from our other northern sites, and in some older museum samples from the Rocky Mountains in Alberta and British Columbia, and even a few specimens from northern Sweden that former Lyman grad student Jade Savage collected more than a decade ago. We now know this new species is widespread in northern Canada and also in Sweden, but the first locality was special enough that Sabrina decided to call the new species Parapiophila kugluktuk.

Parapiophila kugluktuk, a new species from northern Canada (from Rochefort & Wheeler, 2015)

Parapiophila kugluktuk, a new species from northern Canada (from Rochefort & Wheeler, 2015)

But a species doesn’t have to be new to be a surprise. Sabrina also identified a couple of new North American records of species that were previously known only from Europe, or from Europe and Greenland. This is a fairly common occurrence in arctic insects, as well as other arctic species, where the same species is found in both North America and Eurasia. On the other hand, two of the previously known species looked a little too similar, so we looked at as many specimens as we could, extracted and sequenced DNA barcodes, and concluded that, even though they are known under two names, we couldn’t justify treating them as distinct species, so we combined the two under a single name. One new species added, one old species synonymized – a taxonomic trade-off that happens a lot in this sort of work.

We also looked at the distribution of the species from south to north. There was a little surprise here too. Very few species or specimens were collected at boreal forest sites near treeline (in these sites many other fly families were still very diverse in our samples). On the other hand, 16 of the 17 piophilid species identified were collected at low arctic tundra sites on the Canadian mainland. Even on the far northern arctic islands, we collected only five species, but hundreds of specimens. Piophilids seem to thrive on the tundra. They’re tough little flies.

Shiny little survivors.


Rochefort, S. & Wheeler, T.A. 2015. Diversity of Piophilidae (Diptera) in northern Canada and description of a new Holarctic species of Parapiophila McAlpine. Zootaxa 3925: 229-240.

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Who’s that fly and WHAT is it eating? A new paper from the lab

One of the most widely used products of taxonomy is the identification key. A key allows somebody who isn’t a specialist on a particular group to put a name on an unknown species. At least, that’s how it all works in Dream World. Unfortunately, as a frequently used cliché in taxonomy says: many keys are written by people who don’t need them, for people who can’t use them. In other words, the expert who wrote the key knows exactly what he or she means by “wide” vs. “narrow”, or “normal” vs. “pale”, or “modified” vs. “unmodified” (and they haven’t bothered to include any pictures), but that’s no help at all to the student sitting at a microscope 500 miles away and 50 years later, who has never talked to that expert.

We (taxonomists) should be writing keys that are used and usable by people who are not taxonomists, thereby letting us (taxonomists) get on with the enormous task of describing all those new species that aren’t yet in the keys. But a lot of keys aren’t usable. I’m a fly taxonomist and even I can’t work my way through some fly keys, because they’re, well, awful.

We must, as my colleague and mentor Steve Marshall puts it, democratize taxonomy. A few years ago, Steve made a major contribution to the democratization of taxonomy when he launched the Canadian Journal of Arthropod Identification, an open-access, online journal with the express mandate of making identification easier, especially for non-specialists.

Forensic entomologists are one group of non-taxonomists whose work depends on accurate identification of insects. And it’s a lot harder to identify those insects than TV shows would have us believe. One of the main groups of forensically important insects is the blow flies, family Calliphoridae, and there’s a CJAI key for that. But many other insects are part of the carrion community, including a group of little flies that often comes later to the party, colonizing bodies in more advanced stages of decay. This is the family Piophilidae, and they’re small and hard to identify. And because of that, many forensic studies either don’t identify them, or get them wrong. That’s a problem because those studies are potentially missing out on important data. Fortunately for forensic entomology, we now have a North American expert on this family — Sabrina Rochefort, a M.Sc. student in my lab.

Sabrina has just published her first journal paper, along with collaborators Marjolaine Giroux, Jade Savage and me. Sabrina decided to address the lack of a decent key to the piophilid flies for forensic entomology. Her paper, just published in CJAI, is the first well-illustrated key to the species of piophilid flies associated with dead bodies in North America.

Mycetaulus subdolus. A piophilid fly. It eats dead things.

Mycetaulus subdolus. It eats dead things.

Sabrina’s first task was determine which piophilid species are important in forensic entomology and which species tend to eat fungi, decaying vegetation or other things (it’s an ecologically diverse family). A review of the literature helped start building the list, but examination of label data on specimens in museum collections turned up some new records of piophilid species on carrion as well. A third great source of data was an ongoing field study led by our co-authors Marjolaine and Jade on insects associated with carrion in three different regions of Quebec. This combination of fieldwork, museum material, and published records is often how we find and compile taxonomic and ecological data.

The next, and most important, step in building a key is to decide which characters are the most useful in distinguishing species, but also the most easily visible and least ambiguous. There might, for example, be obvious differences in small parts of the male reproductive system, only visible after you dissect specimens. Or it might just be easier to see if the legs are yellow or black. Ideally, a key should be clear to somebody who’s never looked at these insects before. And the easiest way to accomplish that is with illustrations. Good illustrations. Lots of them. With arrows and circles showing important things. And clear language in the key that links to those pictures.

The easiest way to make a key. Does it look like A or does it look like B

The easiest way to make a key. Does it look like A or does it look like B?

Once a species is identified, it’s also very helpful to know a little more about it, so the paper also includes a species page for each piophilid, listing what’s known about its habits, geographic distribution, and any known variation in colour or shape. This sort of natural history information isn’t always included in published keys, but it’s very helpful for people (like, say, forensic entomologists) wanting to know a little more about the fly they’ve just identified.

A species page from Rochefort et al. (2015)

A species page from Rochefort et al. (2015)

Of course, these forensically relevant species are only a small subset of the piophilid flies we can find in North America. They live in a range of habitats, from the arid southwest, to the highest high arctic islands, and they play a range of ecological roles. Those species need to be described, and their phylogenetic relationships established, and good keys need to be constructed for them. Sabrina’s in her office now, surrounded by specimens. She’s on the case.


Rochefort, S., Giroux, M., Savage, J., and T.A. Wheeler. 2015. Key to forensically important Piophilidae (Diptera) in the Nearctic Region. Canadian Journal of Arthropod Identification 27. dx.doi.org/10.3752/cjai.2015.27

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