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?”
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.