Meet the lab: Crystal Ernst

This is the first in a series of posts where each Arthropod Ecology lab member can introduce themselves. First up is PhD student Crystal Ernst:

I’m a Ph.D. candidate in the final stages of my program: these days I’m crunching out analyses and writing papers as I prepare to submit my thesis at the end of the term. As a community ecologist, I spend a lot of time thinking about how and why different species assemble together in space and time. These questions are foundational to the study of ecology and provide the overall framework for my research program, which uses beetles and other ground-dwelling arthropods to study the structure and determinants of terrestrial animal assemblages.

PhD student Crystal Ernst installing pan traps along the Dempster Highway (Yukon)

PhD student Crystal Ernst installing pan traps along the Dempster Highway (Yukon)

I have spent my summers conducting field research in gorgeous, remote regions of our northern territories, including Kugluktuk Nunavut and the Dempster Highway in the Yukon. My colleagues, members of the Northern Biodiversity Program, have contributed to the collection efforts as well, resulting in specimens being obtained from twelve different locations in the boreal forest, the subarctic and high arctic, spanning Canada coast to coast. I’m now neck-deep in the joy of interpreting the stories contained in my collection of specimens.

Specimens in pan trap (photo by C Ernst)

Specimens in pan trap (photo by C Ernst)

 

Sorting specimens back in the lab

Sorting specimens back in the lab

I’ve taken two approaches with this work. First, I’ve used a fairly traditional taxonomic approach to studying these animals: by identifying them morphologically (with a microscope and identification keys), I can associate each individual with a known insect species – although some new species have also been discovered! With this information I can describe the species richness (diversity) and distributions of different beetles in the north, and see which species are associated with each other at different northern locations. Secondly, I’ve looked at my arthropods from the perspective of their ecological functions – their roles in their environments. For example, some insects are responsible for pollenating plants, others are important decomposers, and others still are predators; arthropod assemblages can therefore be described in terms of the diversity and dominance of different functional groups. I am in the process of comparing taxonomic and functional assemblages found across northern Canada, and working to determine what aspects of their ecosystems (things like: temperature, wind, and sunlight; the diversity and structure of the plant community in which they live; soil characteristics) are associated with the way these assemblages are structured, and how they change over time and across space.

Three color morphs of Blethisa catenaria, a rare subarctic species (H. Goulet)

Three color morphs of Blethisa catenaria, a rare subarctic species (H. Goulet)

A fun complementary topic I’ve researched is the relationships between some high arctic ground beetles and a fascinating group of parasites called hairworms. I found a number of beetles from different locations to be infested with these worms; in one instance almost a quarter of the beetles were infected! The parasites are aquatic as adults and must first infect an aquatic insect (like a mosquito larva) before being transmitted to a terrestrial host (like a beetle) via the predation of the aquatic host by the terrestrial insect. To complete their life cycles, the worms somehow compel the beetles to enter the water, effectively forcing them to drown themselves so that the worms can emerge safely into their aquatic habitat. This discovery suggests an important link between the creatures living in terrestrial habitats and those in aquatic habitats and tells us about the arctic food chain: beetles must be eating mosquitos or other insects that have aquatic larval/immature stages. These prey items may, in fact, be a very important source of food. More work needs to be done to confirm this! In the meantime, I am excited to have found these associations – the fact that these particular species of beetles can be hosts for hairworm parasites is new information, and it appears that the parasite itself is a new species!

Pterostichus caribou with hairworms (C. Ernst)

Pterostichus caribou with hairworms (C. Ernst)

When I’m not writing my thesis or putting obscure little black beetles on pins, you can probably find me working at McGill’s Teaching and Learning Services, enjoying my time as a teaching assistant, networking on Twitter, mucking around in my vegetable garden (or putting said veggies in jars), walking my dogs, enjoying nature while canoe tripping with my partner, poking wildlife, or lifting heavy things at the gym. I’m on the hunt for a fantastic postdoctoral position that will allow me to continue studying different communities of living things in other ecosystems, and that factors that affect how they’re put together, and I’m excited about the many opportunities out there!

Quiet Ocean

My tweets and photos about the Arctic caught the attention of the super-talented, all-around great biologist/naturalist (& musician) Nash Turley, and he wrote a poem. It’s lovely.

QUIET OCEAN

White ice is broken by incessant glow

Sea comes alive, to sing, so grow

Anadromous fins fled winter extremes

Return to dance in shimmering streams

Churning chilled seas offer brief respite

Inviting colored stones to reflect light

Crystalline plane is dazzling effect

Shaken silhouette as I stop and reflect

Here’s one of the photos that inspired this poetry.

Good fishing place

(Thank you, Nash, for the discussions, the poem, and for allowing me to post it here.)

Arctic reflections (Part 2)

I started a post last week about my recent field trip to the Arctic – I was situated in Cambridge Bay (Nunavut) for a week, and here are a few more reflections from that trip.

Screen Shot 2013-08-14 at 9.11.42 PM

Wildlife

Walking across the tundra brings sights of circling rough-legged hawks and the sounds of jaegers. We were able to find spots where the hawks like to sit (at higher elevations, on a pile of rocks and boulders). The vegetation is particularly rich under these perches, as the nutrient inputs are very high! We could also find feathers, and pellets – these pellets are a tidy package – a mass that represents the undigested parts of a bird’s food, regurgitated. These pellets can be dissected and you can find the tiny bones of small mammals. While in Cambridge Bay it was a particularly good year for lemmings, and thus a particularly good year for hawks, and snowy owls. Each day on the tundra, about a dozen different snowy owls were sighted. They were always just the right distance away, perched beautifully and peacefully on slight rise – a close look with the binoculars showed the owls staring right back, tracking our movements as we were tracking theirs. If you walk little closer, the owls take off, flying low and fast over the tundra.

Bird food. Aka lemming.

Bird food. (otherwise known as lemming).

At times, off in the distance, it was also possible to see black, slow-moving shapes – unusual creatures, shaggy, and foreign to a boy from the south. These were muskoxen – chewing their way across the tundra. While in Cambridge Bay I spent some time with graduate students working on Muskox health, and I learned of the serious disease, lungworm, that is affecting these stunning mammals. Lungworm has been known from the mainland for some time, but only more recently on Victoria Island – climate change is a possible reason for this change in distribution. These nematodes use slugs or snails as intermediate hosts. Yes, there are slugs and snails in the Arctic!  Finally, it’s pretty difficult to talk about Cambridge Bay without mentioning the fish. The traditional name for this place, in Inuinnaqtun, is “good fishing place“, and that is an apt description. We ate fresh fish every day, enjoying Lake trout, Greenland cod, and the most delicious of all, Arctic Char. We were blessed with amazing weather during my week in Cambridge Bay, and our Sunday afternoon fishing trip on the ocean was picture-perfect.

Good fishing place.

Good fishing place.

Landscape and light

It’s hard to explain the North to people who have never experienced it, but let me try:

The landscape is breathtaking in its starkness.  The tundra rolls out like a grey/green/brown carpet, as far as the eye can see. It’s broken up by ponds, streams, and lakes, and broken up by slight changes in elevation. This results in a landscape that ripples with shadows and colours; a landscape that meanders, curls and curves depending on the underlying bedrock, sediment, glacial till, and permafrost. 

At first glance, the Arctic tundra appears homogenous, but after walking for hours upon hummocks and through cotton grass, you start to see the diversity of ecosystems, and the heterogeneity in microhabitats. It’s a landscape that is forever changing and providing plants and animals opportunities as well as challenges. I was in Cambridge Bay in early August, and it was evident that the summer season was ending.  In addition to the signs from the plants (lack of flowers) and wildlife (geese were moving in, in flocks; butterflies were seldom seen), the strongest evidence was the light. During the week I was in Cambridge Bay, there was about 18 hours of daylight each day, but the land is losing about 5 minutes of light each day – it’s a rapid change. Since Cambridge Bay is above the Arctic circle, it gets 24 hours light in June and early July, but by mid-August, summer is winding down. This means, however, that you can experience the most stunning sunsets – you can sit for hours and watch the sun approach the horizon from a remarkably shallow angle. The “magic” light is with you for hours. The kind of low light that makes everything slow down.  The kind of light that creates long, dancing shadows, and warms everything in a soft, gentle glow.

Arctic reflections

Reflection

To finish, I wanted to write a little bit about perspective. The Arctic makes you feel close to the earth. When standing on the tundra, the land before you contains no telephone lines, roads or apartment buildings. It’s very much like it was hundreds or thousands of years ago. You could start walking and you won’t likely see anyone else. The Arctic causes you to reflect and slow down. And most importantly, the Arctic makes you feel small. I think that’s an important feeling to have every now and then. The land is vast and old; we are small and young. Let’s remember we are here for a short while, and some of our time is probably well spent out in a forest, on a lake, or hiking the tundra.  Time on the land is time well spent, in part because it causes you to pause and reflect. I think the world would be a better place if we spent a little more time breathing in nature, and remembering what the earth is giving us and on how we ought to respect it a little more.  We owe it everything.

The Arctic makes me think of these things and for that I am grateful.

Screen Shot 2013-08-14 at 9.15.37 PM

Arctic reflections (Part 1)

So many clichés  – the Arctic is a vast, stark landscape. In summer, a land of endless days, swarms of mosquitoes and rivers teeming with Arctic char; snowy owls flying low over the tundra; Muskox roaming the lands.

The clichés are true. I’ve been north many times, and each time the effect is stronger. Each time the landscape leaves a deeper impression. Over a couple of blog posts, I want to share reflections about the Arctic from my recent field trip to Cambridge Bay (Nunavut), and try to explain why I love it so much, and why Arctic research is my passion. I’ll also share a few of my favourite photographs from the trip.

Mt Pelly

Arctic Arthropods

I often write that “Arctic biodiversity is dominated by arthropods” and I stand firmly behind that statement. Despite the latitude of Cambridge Bay (at 69 degrees North), the tundra is alive with butterflies, bees, low-flying dipterans, and spiders.  On a warm day, you can sit in the tundra and watch the careful movements of spiders as they navigate their three-dimensional world, seeking prey, or simply sunning themselves.  Over the past few years our research team has documented over 300 species of spiders living across the Arctic and sub-Arctic, and although diversity drops at high latitudes, there are still over 20 species known from the low Arctic Islands, dropping to fewer than a dozen as you approach 80 degrees North.

Arctic wolf spider (Lycosidae), genus Alopecosa

Arctic wolf spider (Lycosidae), genus Alopecosa

Under rocks in flowing water you can find black fly larvae, swaying in the current. Sometimes you find the shield-shaped pupal cases, and if lucky, you can see the emerging adults. These emerging adults are sometimes adorned with red mites. There are arthropods living within the protection of Arctic willow; careful examination of Salix reveals red ‘berries’ which are actually galls. Opening these reveals a hidden life. A secret, protected room containing the larvae of a Hymenoptera.

An Arctic Lepidoptera

An Arctic Lepidoptera (genus Boloria)

Research

A few years ago, the Federal Government announced a new Canadian High Arctic Research Station (CHARS), and it is to be built in Cambridge Bay over the next several years. This station will support and facilitate research in the North, in many different ways, from studies about effects of climate change on permafrost, to research on marine mammals. I am going to do my own research in Cambridge Bay, but with the aim of integrating research about arthropod biodiversity with other Arctic studies. I also hope to help in the development of a long-term monitoring plan, using arthropods as one of the focal taxon. Arthropods can tell us a lot about the world, and how it is changing, and long-term data are needed to ensure we have a clear sense of when ‘change’ is change that we need to pay particularly close attention to.

A malaise trap on the tundra - designed to collecting flying insects

A malaise trap on the tundra – designed to collect flying insects

I was in Cambridge Bay to start to develop these kinds of projects, and to get to know the town, community and the land.  I also wanted to collect insects and spiders in the Arctic in the late-season. I’ve worked in the Arctic a lot over the last several years, and although we have done full-season (i.e., June-August) collecting on the mainland, our laboratory does not yet have a clear idea about seasonal occurrence of different species occurring on the Arctic islands. Therefore, I was doing some collecting so that data could be gathered about arthropods on Victoria island and the end of the summer. For all these reasons, Cambridge Bay was my ‘research home’ for a week or so.

History and People.

Arctic regions of Canada have a rich history – and a history that is both tragic and awe-inspiring. Residential schools, relocation programs and stories of substance abuse, are all part of the darker side of this history. For hundreds of years, Europeans saw the Arctic as a wild land that required navigating, and a land that contained a bounty of riches, from whales to minerals. A bounty that was available for the taking. The stories are remarkable, and evidence of them remain in places like Cambridge Bay, including the influence of the Catholic church and the wreck of Amundsen’s ship, the Maud.  The search for Franklin’s lost ships continues – while I was in Cambridge Bay, a ship departed, in search of the Erebus and the Terror.

The remnants of a Catholic church, built in Cambridge Bay in the early 1950s

The remnants of a Catholic church, built in Cambridge Bay in the early 1950s

The Maud, in its resting place. The townsite of Cambridge Bay is visible in the background

The Maud, in its resting place. The townsite of Cambridge Bay is visible in the background

There has been a rebirth, however – Nunavut is a place of Inuit pride, and includes a wonderful balance between old traditions and new. The Inuit are marvellous – a people exhibiting patience, perseverance, kindness, good humour, and ingenuity. I heard stories of how runners on sleds could be made of frozen bodies of Arctic char, and the cross-braces from bones of wildlife, and frozen mosses would adorn the tops. If times were really tough, parts of the sled were edible.  Today, wood and rope is the preferred construction material!

Sled on the tundra: waiting for winter.

Sled on the tundra: waiting for winter.

Inuit culture is alive and well. I was lucky to spend time on the land with some of the locals, and I learned of edible plants, leaves that can be burned to ward of mosquitoes, and about the lice on arctic hare pelts.  The Inuit are also fabulously artistic, well known for their carvings from bones and fur.

Looking out towards the Northwest Passage.

Looking out towards the Northwest Passage.

Stay tuned for Part 2, to come next week…

Inuit Art – arthropod style

Thought I would do a quick post from Cambridge Bay – I have managed to find some decent WIFI so I am taking advantage this morning! Once I am back south, I will post more detailed accounts of my adventures in the Arctic.

Inuit carvers are known world-wide for their depictions of Muskox, polar bears, seals, and other wildlife.  “Bugs”, however, are rare as pieces of art from the Inuit. I was therefore thrilled to see a mosquito made from sealskin at a shop in Cambridge Bay, made by a local artist. It’s a wonderful depiction! And the mozzie looks almost cute and cuddly….

Sealskin mosquito

Sealskin mosquito

Another local carver, Johnny, comes by our place with some regularity. Earlier this week I chatted with him about my interest in insects and spiders and he looked at me with a twinkle in his eye. “I’ve never done any bugs before, let me think about that” were his words.  I believed him – I have travelled in the Arctic quite a bit, and have never come across a carving that depicts arthropods.

Last night there was a knock at the door. Johnny approached, holding out his arthropod, made from caribou antlers. WOW. I was so touched that he went away and worked on this carving for me. To me, it looks like a spider, which is quite fitting.

Inuit carving of an arthropod (a spider, in my opinion!)

Inuit carving of an arthropod (a spider, in my opinion!)

 

UPDATE (11 Aug) - Johnny came by the house again last night. He allowed me to take his picture, and I’ll share it with you, here.

The artist: Johnny Udlaoyak Jr., of Cambridge Bay, Nunavut.

The artist: Johnny Udlaoyak Jr., of Cambridge Bay, Nunavut.

 

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

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.

Spiders as catalysts for ecosystem development

It is well known that spiders are effective at dispersal and colonization, in part because of their ability to ‘balloon‘ – small spiders (i.e., immature specimens, or adults of species that are small) will release a strand of silk and let the wind pick them up and carry them far distances.  This passive ability to disperse has served spiders well, and enabled them to be among the first animals to colonize new habitats.  For example, after the eruption of Mount St Helens, the depopulated Pumice Plain was re-colonized over time, and biologists kept an eye on what was dropping from the skies.  Not surprising (to me!) was that spiders represented a lot of this ‘aerial plankton‘ – Crawford et al. (1995) reported that spiders represented “23% of windblown arthropod fallout and contributed 105 individuals per square meter“.

A spider about to launch!  Photo by Bryan Reynolds, reproduced here with permission. Please visit his work!

A spider about to launch! Photo by Bryan Reynolds, reproduced here with permission.

Many, many people have recognized this amazing ability of spiders to get to places effectively and quickly.  During his voyages on the HMS Beagle, Darwin observed and commented on this. He noticed spiders landing on the ship when they were far offshore.  Here’s a lovely quote:

      These, glittering in the sunshine, might be compared to diverging rays of light; they were not, however, straight, but in undulations like films of silk blown by the wind.

-Charles Darwin, Voyage of the Beagle, 1832

A wonderful paper titled “Distribution of Insects, Spiders, and Mites in the Air” (Glick 1939) also discusses aerial plankton. In this work, Glick reports on how a plane was used to collect arthropods in the skies – this was done by modifying the plane so it had a collection net attached to it.  Spiders were among the most commonly collected taxa, and were found up to 15,000 ft in altitude.   Glick followed this up with work published in 1957, and spiders were again reported as common aerial plankton.

Convinced?  Spiders really are everywhere and can get anywhere – from dominating the tundra, to floating far above as tiny eight-legged aeronauts.

Screen Shot 2013-04-08 at 11.06.08 PM

This takes me (finally) to the point of this post, and some reflection about a paper by Hodkinson et al. (2001), titled “What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic – some counter-intuitive ideas on community assembly”.  In this work, the authors provide some data about aerial plankton in a series of sites representing different stages of succession in Midtre Lovénbreen – a ‘small valley’ glacier in Spitsbergen (a Norwegian high Arctic Island).   This forum paper was meant to present an idea about ecosystem development in the Arctic, with a focus on spiders and other aerial plankton and their relationship to nutrients.

  • Spiders are among the first to arrive due to their amazing abilities at dispersal and colonization.
  • Many spiders will just die, and their sad, little bodies will decompose and leave behind nutrients.
  • Many of the spider species that arrive will build webs, and the silk contains many nutrients. Regardless of whether the silk successfully captures prey, the silk will eventually be a hot-spot of nutrients.
  • A lot of other aerial plankton will hit these webs – this will include other arthropods (Hodkinson et al. rightfully point out the importance of Chironomids, or midges, as key prey for spiders in the north) and these prey may or may not be eaten by spiders.  The aerial plankton also includes other ‘debris’ that would be floating around (fungal spores, dirt, etc).  The webs capture all these goodies, and act as a concentrated area for a growing soup of nutrients.
  • The spider webs will collect moisture.  In Arctic systems, dry polar-deserts, and many other newly created habitats, the accumulation of moisture is rather essential for continued ecosystem development.

Taken together, Hodkinson et al. (2001) argue that spiders and their webs represent little pockets of concentrated nutrients in landscapes that are void of much other life.  These hotspots could be catalysts for ecosystem development in systems that are starting from scratch.  I really like this idea – not only does is stir up the imagination (little spiders gently falling from the sky, landing on habitat never before touched by animals, and providing the start of an ecosystem…), it really makes some biological sense.  Ecosystem development requires nutrients and substrates – of course, these would both be available without spiders, but our eight-legged friends are helping move things a long a little more quickly.

The paper by Hodkinson et al. has been cited less than I would have expected.   Although they don’t provide any experimental data, their ideas are interesting and relevant and should be studied in detail. Recently, a few papers have come out that are taking the ideas to the next level.  Konig et al. (2011) studied arthropods of glacier foregrounds in the Alps. They found that although Collembola and other ‘decomposers’ are quite important in early successional stages, overall, generalist predators (including spiders) were dominant and using stable isotope analyses, they showed that these generalist predators often ate each other – an interaction known as intraguild predation.

I often discuss Hodkinson et al.’s (2001) paper in lectures, and invariably I get the question “If spiders are first to arrive, what do they eat?“. I typically answer that spiders eat other spiders, and it’s reassuring to see literature that supports this claim.  In turn, intraguild predation itself contributes further to the accumulation of nutrients (more sad, little spider bodies littering the landscape…).

Placing this work in a more general framework, these ideas are pointing to the increased importance of predators in overall nutrient dynamics in ecosystems. I was thrilled to see a paper by Schmitz et al. (2010) that argues “predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes“. Bingo. This is exactly what Hodkinson et al. were arguing – predators, such as spiders, can arrive quickly to an area, and in the context of newly formed ecosystems, may provide a hotspot for nutrients in an otherwise desolate landscape.

Although the Hodkinson et al. paper is over a decade old, it’s still relevant, and quite important. I suspect that if more newly created habitats are studied in detail, spiders will indeed prove to be catalysts for ecosystem development.

References:

Crawford, R., Sugg, P., & Edwards, J. (1995). Spider Arrival and Primary Establishment on Terrain Depopulated by Volcanic Eruption at Mount St. Helens, Washington American Midland Naturalist, 133 (1) DOI: 10.2307/2426348

Hodkinson, I., Coulson, S., Harrison, J., & Webb, N. (2001). What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic – some counter-intuitive ideas on community assembly Oikos, 95 (2), 349-352 DOI: 10.1034/j.1600-0706.2001.950217.x

König, T., Kaufmann, R., & Scheu, S. (2011). The formation of terrestrial food webs in glacier foreland: Evidence for the pivotal role of decomposer prey and intraguild predation Pedobiologia, 54 (2), 147-152 DOI: 10.1016/j.pedobi.2010.12.004

Schmitz, O., Hawlena, D., & Trussell, G. (2010). Predator control of ecosystem nutrient dynamics Ecology Letters, 13 (10), 1199-1209 DOI: 10.1111/j.1461-0248.2010.01511.x

ResearchBlogging.org

A special thanks to Bryan Reynolds for permission to use his photograph of the dispersing Pisaurid spider.  Please visit his work here.