Spiderday (#23) – Happy Holidays

SPIDERDAY is finally back – it’s been a few weeks, but the end of the term has been hectic. However, it’s time to catch up on some great Arachnid-themed links from the last little while.

This will also be my last post of 2015, so I’ll also take this opportunity to THANK YOU for reading and commenting on this blog. I also wish everyone a Happy Holidays! Arthropod Ecology will certainly keep on truckin’ in 2016.

Here's looking at you... A close up of an Araneidae, from Insects Unlocked.

Here’s looking at you… A close up of an Araneidae, from Insects Unlocked.

Collectors cards, Arachnid style.

Collectors cards, Arachnid style.

Heating, cooling, and trying to drown Arctic pseudoscorpions

The Beringian Arctic pseudoscorpion is a charming Arachnid, living under rocks near sub-arctic rivers and streams, in primarily unglaciated parts of the Yukon. It has captured my fascinating for years, and the story of its natural history is starting to unfold. However, some fundamentals about the biology of Wyochernes asiaticus remain unknown: as the most northern pseudoscorpion in North America, how does it survive in such cold climates? How is it adapted to frequent flooding that occurs in its primary habitat, next to streams and rivers?

The Arctic pseudoscorpion, Wyochernes asiaticus

The Arctic pseudoscorpion, Wyochernes asiaticus

Science is a collaborative process, and I teamed up with two thermal biologists to start to answer some of these physiological questions. PhD student Susan Anthony and Prof. Brent Sinclair*, both from Western University in Ontario, came to the Yukon with us last summer, and together we collected pseudoscorpions at Sheep Creek, just north of the Arctic Circle. Part of Susan’s PhD research is about the thermal biology of Arachnids, so Susan and Brent wanted to see what we could learn about Arctic pseudoscorpions. They brought the wee arachnids back to Ontario, and Susan ran a series of experiments, resulting in a recent publication (in Polar Biology).

Susan Anthony and Brent Sinclair, both from Western University.

Susan Anthony and Brent Sinclair, both from Western University.

The experiments may sound a little cruel, but they are the standard approach when studying some of the cold tolerance, thermal biology and physiology of arthropods. Susan heated up and cooled down the critters, and discovered that they can survive up to about 38 degrees Celsius, and down to about -7 degrees Celsius. The upper threshold is relatively low compared to other arthropods, which makes sense since W. asiaticus lives at high latitudes. Because the specimens didn’t survive freezing, we know it’s ‘freeze avoidant’ rather than ‘freeze tolerant’. This is aligns with what we know from many other northern (or southern! i.e, in the Antarctic) arthropods. Presumably the pseudoscorpions adapt to the north by being able to supercool, or perhaps by cryoprotective dehydration,. However, its lower threshold isn’t that low, given the extreme cold winter temperatures in the Yukon. But since our collections were in the mid-summer, this might mean it’s not yet started to adapt, physiologically, for the colder winter conditions.

The next experiments involved immersing the pseudoscorpions in water and seeing how long they survive. This was done because we were very curious to know how these tiny animals might live in habitats that flood frequently. Amazingly, 50 percent of the arachnids survived under water for up to 17 days (!), and after testing with de-oxygenated water, Susan had a similar result: they certainly weren’t relying on oxygen in the water for breathing. Susan did notice, however, that they appeared to have a silvery bubble or ‘film’ around their bodies when immersed so we assume they used this air bubble for breathing during the immersion period, something known from other arachnids.

Sheep Creek, Yukon - a habitat that frequently floods: now we know how the tiny Arachnids survive the flooding!

Sheep Creek, Yukon – a habitat that frequently floods: now we know how the tiny Arachnids survive the flooding!

Putting this in the context of the pseudoscorpion’s habitat in the Yukon: it seems that the sub-arctic rivers in the Yukon typically flood for periods up to 10 days, in the spring. Our little arachnid likely just hunkers down in their habitats under rocks, breathing from air trapped around its body, waiting for floodwaters to recede.

I’m very excited about this paper, in part because of what we have learned that links the ecology of the species to its physiology. I’m also excited because this work represents a major advancement in the fundamental knowledge about Arachnids. Our work is the first to uncover any basic biology related to the physiological adaptations of pseudoscorpions to cold/heat and to immersion tolerance.

This is kind of stunning: the Pseudoscorpiones are an entire Order of Arachnids, yet nobody has ever worked to figure out how they adapt, physiologically, to extreme environmental conditions. AN ENTIRE ORDER! And it’s 2015! An analogy would be figuring out that some butterflies (Order Lepidoptera) bask in the sun, to thermoregulate. Or, like figuring out how ducks (Order: Anseriformes) don’t freeze their feet when standing on ice. These are ‘textbook’ examples of thermal biology and physiology – such facts could be considered common knowledge. Yet looking to the Arachnids, the story of the thermal biology of pseudoscorpions has only just begun. One paper at a time, we will continue to make progress.

The Arctic pseudoscorpion: it has stories to tell. Photo by C. Ernst, reproduced here with permission.

The Arctic pseudoscorpion: it has stories to tell. Photo by C. Ernst, reproduced here with permission.

As Tschinkel & Wilson state, every species has an epic tale to tell. Even tiny arachnids that live under rocks above the Arctic circle are proving interesting for many scientific disciplines: each chapter of its story is starting to unfold, and I’m quite sure there are a lot of very interesting chapters still to come.

Reference:

Anthony, S.E., C.M. Buddle and B.J. Sinclair. 2015. Thermal biology and immersion tolerance of the Beringian pseudoscorpion Wyochernes asiaticus. Polar Biology.

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*A sincere thanks to Brent and Susan for including me on this paper, and for being willing to come to the Yukon with our team, to do collaborative research. I’ve learned a great deal in the process, and am delighted that partnerships between ecologists and physiologists can work out so well.

Spiderday (#22)

It’s been a couple of weeks, but nevertheless, here is another edition of SPIDERDAY! All the best Arachnid-themed links, pulled from the web in the last little while.

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

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Curiosity, passion and science: On the natural history of an Arctic pseudoscorpion

I’m pleased to announce a publication about the natural history of a tiny, wonderful arachnid: the pseudoscorpion Wyochernes asiaticus.

The Arctic pseudoscorpion Wyochernes asiaticus (copyright C. Ernst, reproduced here with permission)

The Arctic pseudoscorpion Wyochernes asiaticus (photo by  C. Ernst, reproduced here with permission)

I’ve published quite a few papers, but this one is really special: it’s special because it’s about an obscure creature for which virtually *nothing* was known. It’s about a species with a fascinating distribution. To me, it’s an epic tale about a species that nobody really cares that much about. It’s special because it is research that was done just out of pure curiosity and fascination: there was no larger purpose, no great problem to solve, and no experiments to run*. It was based on observation and observation alone, and it was a long slog – done over many, many years (it took about 7-8 years to pull together this story, and this story is really only a prologue). Fundamentally this research was about trying to gather some base-line data about a small animal living in a big landscape.

The big landscape: A river above the Arctic circle: our pseudscorpion friend can be found under the rocks alongside this river.

The big landscape: A river above the Arctic circle: our pseudscorpion friend can be found under the rocks alongside this river.

This work presents some life-history data about a fascinating northern pseudoscorpion species, occurring only in the north-west of North America. As far as I know, it occurs only in regions that were primarily unglaciated during the last glaciation event which covered pretty much all of the northern half of the continent. However, unlike other Beringian species (e.g., the wooly mammoth), this little arachnid did not go extinct but rather continues to thrive in its somewhat unusual habitat under rocks, near rivers or streams.

After collecting and measuring nearly 600 specimens, I can now tell you a bit more about the species distribution in North America, and provide some insights into its life history traits. For example, larger females tended to have higher clutch sizes, a very common and well-known pattern with other arachnids, but there was certainly a paucity of data about this for pseudoscorpions. I also know that all its life stages can be collected in the Yukon in July, and that females can carry around quite a few young (over a dozen!).

But that’s about it. Beyond those fundamental life history measurements and comments on its distribution, the bulk of the species biology remains a mystery.

It may be possible to look at this work as a failure. Heck – a LOT of specimens were collected, by many, many enthusiastic helpers. It took some resources to get the work done (although it was mostly through stealth). A lot of time was spent at the microscope, and it certainly took a bit of time to pull together the paper. And what for? We still don’t know very much about the species: how does it disperse? How does it overwinter? How does it survive flooding of its habitat? How restrictive are the habitat affinities of the species? Do females and males tend to hang around the same rock, or do they mill about with others? What does it eat?

I don’t see this as frustrating, or discouraging, because it’s a start. Before thinking about bigger questions in ecology and evolution, your first need some basics. Only then is it possible to ask broader questions about, say, phylogeography, dispersal limitation, or behaviour.

I hope this work encourages others to seek out and discover new and interesting things about the unnoticed species that walk underfoot, live in tree-tops, swamps, or beneath park benches.

The Arctic pseudoscorpion, Wyochernes asiaticus

Another image of the Arctic pseudoscorpion, Wyochernes asiaticus taken during the 2015 field season

I was very pleased to publish this work in the Canadian Field-Naturalist. Sure, it’s not a ‘high impact’ journal, but it’s a rather special and unique journal for being an excellent location to publish work on the natural history of our species. I hope others consider this journal as an outlet for their curiosity-driven science. Over time, I hope the pendulum does swing, and as a scientific community we really embrace the value of “basic” natural history data. Without a fundamental working knowledge of our species we are hamstrung when it comes to solving the big environmental challenges facing our planet. It’s time to play catch-up. Let’s worry less about impact factors and show some love for smaller journals that are brave enough to keep on publishing about natural history. Let’s spend time observing our natural world, collecting interesting data just because.

I ended my paper with a paragraph about what it felt like to do this research. I am so thankful the editors allowed me to keep this paragraph. It’s important, and reflects my long-standing belief that the lines between a subjective love of nature, and objective observations about nature, should be blurred. They certainly are for me.

In conclusion, observing these marvelous animals in one of the most beautiful areas of the planet, was gratifying, awe-inspiring, and helped solidify a love of natural history. What has been learned is only the prologue to a truly astounding epic: many more discoveries await.

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*Please check out this amazing blog post about the value of ‘observation’ to ecology. It relates closely to what I have written.

© C.M. Buddle (2015)

Spiderday (#10)

Spiderday is back! I was away for a little while, but am happy to bring you some arachnid stories pulled from the web over the last little while.

But first, do check out photos from Colin Hutton:

A tailless whip scorpion, by Colin Hutton (reproduced here with permission)

A tailless whip scorpion, by Colin Hutton (reproduced here with permission)

Pseudo

 

Yukon field work: Arachnids, landscapes, and the inspiring North

It’s a dream for an arthropod ecologist: a dramatic biome transition from boreal forest to subarctic tundra, a beringian landscape, and diverse and abundant insects and spiders. I have just returned from field work along the Yukon’s Dempster Highway, Canada’s only road to cross the Arctic circle. And again, I was not disappointed!

A stretch of the Dempster Highway

A stretch of the Dempster Highway

This year’s expedition was focused on three projects:

1) Tiny, wonderful arachnids:

On this trip, I continued to document the distribution of an arctic Pseudoscorpion, Wyochernes asiaticus. This is a beringian arachnid, known from the old world, and known in North America from almost exclusively unglaciated parts of the Yukon and Alaska. Like wooly mammoths and giant short-faced bears, these tiny arachnids roamed North America while the rest of the top half of the continent was buried under ice. But unlike the mammoths and giant short-faced bears, the Arctic Pseudoscorpion is not extinct! It’s a relict of the past, thriving today under rocks near beringian rivers and streams. I have been working on this species for many years (and a life history paper about this arachnid will appear in the Canadian Field-Naturalist sometime this month), and each time I visit the Yukon, I leave with more questions, and more specimens. This time, I collected some animals to hopefully work on their population genetics: I am curious about the relatedness among the populations from different watersheds along the Dempster Highway (by the way, I am seeking collaborators [phylogeographers!] for this work… If interested, let me know!)

The Arctic pseudoscorpion, Wyochernes asiaticus

The Arctic pseudoscorpion, Wyochernes asiaticus

2) Northern food webs:

I have left my PhD student Shaun Turney up in the Yukon (along with his field assistant) where he is working on characterizing the arthropod-based food webs along the latitudinal gradient of the Dempster Highway. Past research has given some hints that northern food webs may be atypical, but to fully test this we decided to characterize the entire fauna from 1 x 1 m patches of the tundra. This involved placing tents over the tundra, and Shaun collected critters within those tents, and even “vacuumed” the tundra within the square metre. Shaun started this work near the stunning Richardson mountains above the arctic circle, and over the month of July, will repeat the sampling at different locations along the Dempster Highway.

Shaun Turney, vacuuming the Tundra.

Shaun Turney, vacuuming the Tundra.

3) Thermal biology of wolf spiders

Colleagues from Western University joined me in the Yukon to start some projects related to the thermal biology of the extremely abundant Pardosa wolf spiders which inhabit the tundra. There are several species that occur along the Dempster Highway, and when the weather is good, it’s quite possible to collect hundreds of individuals over the span of several hours. Past work has suggested the density of these spiders is about 0.5 per square metre, and those past estimates certainly seemed accurate on this trip also! The spiders will be taken back to their lab, and I am eager to find out how northern Pardosa may be adapted to Yukon conditions.

Searching for wolf spiders on the Tundra

Searching for wolf spiders on the Tundra

All the sciency parts of our field work were exciting and gratifying, but there are other reasons why the Yukon is special*: it is a breathtakingly beautiful place. From stubby black spruce trees to tufts of tundra-dwelling cotton grass, every turn of the highway or footstep over a hummock is a treat. It’s not all easy (hordes of mosquitoes at some of the campgrounds, or being driven off the tundra by cold rains and strong winds), but it is all inspiring.

The lines between science and passion are blurred on the tundra, and that is a good thing. Searching for spiders is work that is fun; seeing a northern shrike or watching two lonely caribou dart up a river valley is fun that comes with the field work. I am immensely grateful for being able to hike under midnight sun, and be a northern researcher during the day. I am delighted to be able to discover some of hidden secrets of the Yukon.

The northern landscape, near the Yukon-Northwest Territory border.

The northern landscape, near the Yukon-Northwest Territory border.

For more photos of the recent trip, check out my Flickr page.

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* my colleague Terry Wheeler shares a passion for the Yukon – here is his post which outlines why he keeps returning to the region.

Spiderday (the fifth)

Here’s your fifth instalment of SPIDERDAY here on the arthropod ecology blog: all the arachnid links from last week:

Pseudoscorpions 'catching a ride' on an insect. Photo by Sean McCann

Pseudoscorpions ‘catching a ride’ on an insect. Photo by Sean McCann

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© C.M. Buddle