Beetles from the North

I’m super-excited to announce new research from the lab, published yesterday with lead author Dr. Crystal Ernst.

Crystal’s paper focused on taxonomic and functional diversity of beetles across 12 sites in northern Canada, ranging from Labrador to the Yukon Territory, and from the bottom of James Bay all the way up to the tip of Ellesmere Island. This work is result of the Northern Biodiversity Program: a multi-institutional collaborative project about the ecological structure of northern Arthropods.

Crystal Ernst, on the tundra.

Crystal Ernst, on the tundra.

The paper was titled “Drivers and Patterns of Ground-Dwelling Beetle Biodiversity across Northern Canada” and in this research Crystal sorted and identified over 9,000 beetles from 464 species, and she classified the species by their functional ecology to assess how functional diversity may vary across the large spatial scale of this project. Instead of re-writing a summary here, I thought to use this blog post as an opportunity to reflect on what I see as the critical findings from this work, and why this is a paper that I’m incredible proud to be a part of.

  • To me, one of the more interesting findings of this work was that the functional diversity of beetles varied by latitude: although beetles do many things (e.g., herbivore, decomposers, carnivores), it doesn’t seem like all these functions happen at all latitudes. For example, although we document an impressive number of carnivores at all the sites, they are relatively more common in the more northern locations. This is a bit peculiar, and suggests that food-webs involving arthropods vary in some important ways depending on the biome. We also document that temperature is a major explanatory variable when considering functional diversity, which raises the important question about potential effects due to climate change. Indeed, should temperatures change in the north, this may affect the functional ecology of beetles, which in turn could affect other parts of the system.

 

Figure 1 from the paper: Fig 1. Map of the 12 study locations (North Pole Azimuthal projection), showing the spatial distribution of functional groups. These were pooled into trophic groups, and the pie charts show the proportion of the total site biomass represented by each trophic group

Figure 1 from the paper: Fig 1. Map of the 12 study locations, showing the spatial distribution of functional groups. These were pooled into trophic groups, and the pie charts show the proportion of the total site biomass represented by each trophic group

  • The research generally supported the well-known pattern in biogeography about how species richness decreases at more northern latitudes. When looking at which environmental variable may explain this pattern, temperature again came out on top. In other words, what beetles are found where is in part due to the temperatures in that region. Climate change scenarios therefore have significant potential effects on beetles in the north: beetles, like most other arthropods, are tightly linked to temperature. Even small changes in temperatures in the north may have big consequences for beetles.
  • One of the other big findings, to me, was the fundamental value of species-level data for an important taxa, across vast areas of Canada. Crystal recorded new Territorial and Provincial records for 15 beetle species, increasing knowledge about northern biodiversity. I’m also pleased that the data are fully available on-line, via Canadensys, so other researchers can access the information, re-analyze data, and benefit from and build upon this work.
  • The Arctic is special: it is a vast, cold, treeless landscape, with blankets of tundra, and permafrost underfoot. But it’s also special for beetles. After Crystal analyzed the community-level beetle data, using ordination methods, it became apparent that assemblages from the Arctic Islands of Canada were distinct from the sub-Arctic and north-Boreal sites. From a conservation perspective this is quite important. To some, the Arctic may come across as a big, ‘life-less’ region, with the odd polar bear roaming about, but in reality it hosts thousands of species, including hundreds of beetle species, and that beetle community is very different from what we find in other parts of North America. Special things deserve recognition and protection.
  • Every journalist I talked to has asked “Why beetles?” This is an easy one to answer: they fill virtually all roles in ecosystems, they are diverse, they are of interest to many people, and they are beautiful. The latter point is an important one, as it is important to capture curiosity and fascination about arthropods.

 

Carabus vietinghoffi. Photo by Henri Goulet.

A northern beetle: Carabus vietinghoffi. Photo by Henri Goulet.

In sum, this was a terrific project to be involved with, and our lab (and our collaborators) are thrilled that the efforts from the Northern Biodiversity program are showing up in the literature (for more examples, check out this, or this).

And rest assured, there’s more to come…

Taxonomist envy and the importance of names

Imagine: seeking, finding, watching, sampling, measuring, comparing, analyzing, imaging and… naming.

These goodies are all part of taxonomy. As Wikipedia defines it, taxonomy “is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups.”

Taxonomists are the true explorers at the foundation of biodiversity science: they are to be appreciated, and I’m envious of their discoveries.

I’ve always been a collector and sorter and feel some kinship towards taxonomists: although when I was young I engaged more in the process of categorizing ‘non-living’ things such as sticks, stamps, coins or rocks. But there were comparisons of shared characteristics: some rocks were pink, with lightening-strikes of white crystal; some rocks were angular and sharp, some were smooth, shaped by time and oceans. Perhaps it’s not surprising that during my PhD I thoroughly enjoyed sorting and identifying almost 30,000 spiders from Canada’s boreal forest. It brought back good memories from my childhood: it felt right.

It matters that this is Arctosa hirtipes instead of "Wolf spider species X"

It matters that this is Alopecosa hirtipes instead of “Wolf spider species X”

I think my experiences are shared with some of my ecology colleagues, especially those who also call themselves ornithologists, mammalogists, or entomologists: many of us like ‘species’, and their names. We think about interesting species in our study systems, and think about similarities and differences, about a place’s history with its species, and the relationship to other species or spaces nearby, upstream of downstream.

But I, like most of my ecology colleagues, are not taxonomists. Instead we exploit and repurpose the good work done by taxonomists (and often not citing their work – oops!). For a concrete example from my own experience: without the taxonomic expertise of great Canadian arachnologists such as Charles Dondale, and colleagues, who described species and then wrote accessible taxonomic keys, my work would be of much lower value. The keys allowed me to get names on things. These names increase the value of the work tremendously.

Despite being retired for many years, Charles Dondale still has an office at the Canadian National Collection of Insects

Despite being retired for many years, Charles Dondale still has an office at the Canadian National Collection of Insects

Let’s look closely at this value: Surely it would be possible have the same main results from my ecological work without having the actual species names? Surely I could have called everything by my own pretend name – a secret code that I could develop – a series of ‘morphospecies’. And, these days, I could have a long code to represent a barcode. Isn’t that enough? In truth, the broad community patterns that I sometimes publish about don’t depend on the names. Rather, these community patterns depend on recognition of different types of things, but the names themselves don’t drive the patterns.

While it’s true that names are only one part of my ecological research, they are a very important part. They provide an important common ground for understanding our biodiversity – they allow us to compare apples to apples in all the right ways. The names are a doorway into a rich history, a life story that perhaps goes back hundreds of years in the literature. It means more to know that Alopecosa hirtipes is running around the Arctic tundra than it does to know it is ‘Wolf spider species X’.

But the name comes at a cost: it means that someone spent their time searching, watching, measuring and comparing; looking at shared characteristics, and putting the species in an evolutionary framework, and perhaps producing a valuable taxonomic key so free-loading ecologists like me can stick a name on ‘Wolf spider species X’. The cost is worth it: taxonomists are as valuable to science as are ecologists, molecular biologists, or physicists.

A glimpse at the grad students hard at work, using microscopes, in my lab. As ecologists, we need taxonomists.

A glimpse at the grad students hard at work, using microscopes, in my lab. As ecologists, we need taxonomists.

Taxonomy is a science that is relevant and important, and despite increased availability of molecular tools, names still matter. We need taxonomists to be our quality control, and bring sense and order to strings of code in GenBank, and help us compare and connect across systems, or among similar habitats. We need the full package figured out for a species: specimens, meta-data, barcodes and names. After that, we need to go further and assess evolutionary history and test hypotheses about relationships among species.

Today is Taxonomist Appreciation Day, but let’s make sure it’s more than one day. Let’s make it something we think about every day: every time we see a Corvus corax fly by, or see a Chelifer cancroides on the wall of our bathroom, let’s remember that every name has a story, and the narrative is brought to life because of taxonomists.

A naturalist and his moquitoes

This is another in the “meet the lab” series – here’s a feature by MSc student Chris Cloutier:

I can’t remember a time when I wasn’t fascinated by the world of creepy crawly things. For as long as I have been able to grasp and crawl I have been collecting and observing insects and spiders. Although my mother wasn’t always fond of the critters I would trek through the house, my parents were very supportive of my curiosities and did their best to nurture my interests. As a family we would go camping and fishing often, introducing me to the world outside of our backyard and ultimately landing me where I am today.
My passion for studying insects began many years ago with my first entomology course in CEGEP. After completion of that program I enrolled at Macdonald campus of McGill University. Before I even started my first semester I got my first real taste of applied entomology, when Chris Buddle hired me for several months during the summer to be his field and lab technician. Let’s just say that from that point onward I was hooked.

While studying at Mac I really started to discover where my interests were in this very diverse field. I was intrigued with the ecology and natural history of insects and the amazing things that they do. I really enjoyed learning about insect-human interaction, and for some reason I was very interested in disease transmission and parasitism and the amazing enzootic pathways they can take.

Chris Cloutier: the man, the naturalist, the legend.

Chris Cloutier: the man, the naturalist, the legend.

My Master’s research began in early 2014. I had been working for several years at the Morgan Arboretum, a forested property owned by McGill, when my employer, and now co-supervisor, Dr. Jim Fyles approached me with the idea of performing some graduate research using the Arboretum as a study area. I jumped at the idea of doing this, and we got Chris Buddle on board right away. My thesis will be analysing the temporal variation of mosquito community composition across a habitat gradient which includes suburban areas, fields and various forested sites within the Morgan Arboretum. One of the reasons for this research is the fact that in many suburban and forested areas around Montreal, mosquito densities reach near intolerable levels during the summer months. This, coupled with the increasing number of cases of arbovirus (arthropod-borne viruses) infections, such as West Nile Virus, the importance of understanding where mosquitoes are located, and when, as well as which species are present is becoming more and more important.
Collection of mosquitoes takes place for 24h once a week for the entire frost free period, typically from April to November in Montreal. The traps I use to collect mosquitoes are quite specialized and are designed to capture only females which are seeking a blood meal (the ones that we worry about on our strolls through the woods!). These traps use a combination of LED light and carbon dioxide to attract the insects. The LED lights draw in mosquitoes from quite some distance, and the CO2, produced with the help of a few kilograms of dry ice, draws them ever closer to the trap. Once in range, a tiny fan sucks them into a mesh catch-bag and they are trapped.

Chris in the field, checking a trap.

Chris in the field, checking a trap.

When not out in the field, I spend most of my time with my eyes firmly attached to a microscope, sorting, identifying, and counting mosquitoes. After my first field season, I have collected just over 43,000 mosquitoes representing 9 genera and approximately 28 species. I am now faced with the task of analysing the data and making sense of all those numbers, which in fact has revealed some interesting patterns already. I’m looking forward to heading out next spring to start all over again.

The hard work.

The hard work.

I consider myself to be a “geek of all trades” with interests in everything from birding, to plants, herps and pretty much everything in between. I rarely leave home without my binoculars, and during the summer I almost always carry some vials, an aerial net and several field guides (yes, I often get some strange looks…). I’m also a husband and more recently, a father too. My wife still hates mosquitoes but I feel her coming around slowly, and my daughter doesn’t know it yet, but she will be spending an awful lot of time outdoors with us.
Follow me on twitter @C_Cloutier15 or email me at christopher.cloutier@mail.mcgill.ca if you would like to know more about what I am up to and how things are going with my research.

Meet Shaun Turney and Fuzzy Cognitive Mapping

This is another in the series of “Meet the arthropod ecology lab“: Meet PhD student Shaun Turney, and a neat project he’s been working on…

I joined the lab in September and I’ve been really enjoying my first months as a PhD student. I haven’t done any field work yet so that means no specimens to ID or field data to crunch. Instead I’ve been occupying my time very happily playing on the computer. I recently released an R package on CRAN for Fuzzy Cognitive Mapping called “FCMapper”, in collaboration with Michael Bachhofer. It is based on FCMapper for Excel, distributed at http://www.fcmappers.net/joomla/, developed by Michael Bachhofer and Martin Wildenberg. Fuzzy Cognitive Mapping is really cool and you should try it out!

Shaun, in the lab, thinking about food-webs.

Shaun, in the lab, thinking about food-webs.

Recently I’ve become interested in graph theory and all that it has to offer to ecology. Anything that can be represented as boxes and arrows (or lines) can be represented as a graph (in the graph theory sense) and can be analyzed using graph theory tools. I LOVE box and arrow diagrams. Like, maybe an inappropriate amount. Any paper that I’ve printed out and read has at least two or three box and arrow diagrams scribbled into the margins. My notebook is filled with box and arrow diagrams from lectures that I’ve attended or random thoughts that have passed through my mind while I’m sitting on the train. Some people think in words, some in pictures, but I think in boxes and arrows. So you can imagine my enthusiasm as I’ve discovered over the past year that there exists a whole body of mathematics that can represent and analyze box and arrow diagrams.

My latest favourite graph theory tool is called Fuzzy Cognitive Mapping. It can be understood by breaking down the term into its component words. A “cognitive map” in this case is when you represent a system as interconnected concepts. Boxes and arrows, in other words. The “fuzzy” part refers to fuzzy logic. Fuzzy logic is logic that deals with approximate rather than exact values. So to make a fuzzy cognitive map, you make a box and arrow diagram and assign approximate values to the arrows (positive vs negative, weak vs strong relationship). The concepts are then allowed to affect each other until they come to an equilibrium. The exciting part is that then you can try out scenarios! For instance, you could fix one (or more!) concept to be a high or low value and see how it affects the rest of the system. In the context of ecology, one use is to explore potential ecosystem management scenarios (ex, http://en.vedur.is/media/loftslag/Kok_JGEC658_2009.pdf).

If Fuzzy Cognitive Mapping sounds interesting to you (and it should!), you can download the package from CRAN. Michael Bachhofer and I plan to create a tutorial in the spring, but until then you are welcome to email me if you can’t figure out how to use the package.

Download here: http://cran.r-project.org/web/packages/FCMapper/

A graphics output for a toy example I was playing with the other day. It is a cognitive map of things which might affect spotted owl abundance. FCMapper uses igraph for visualization. The thickness of the arrows represents the strength of the relationship and the color represents the direction (red=negative, black=positive), as assigned by me. The size of the circles represents the "size" of each concept at equilibrium, as determined using the nochanges.scenario function in FCMapper. Think of the fun maps you could make for your favourite study system!

A graphics output for a toy example I was playing with the other day. It is a cognitive map of things which might affect spotted owl abundance. FCMapper uses igraph for visualization. The thickness of the arrows represents the strength of the relationship and the color represents the direction (red=negative, black=positive), as assigned by me. The size of the circles represents the “size” of each concept at equilibrium, as determined using the nochanges.scenario function in FCMapper. Think of the fun maps you could make for your favourite study system!

Take the active learning challenge

Dear Instructors,

Here’s your challenge: Include active learning activities in every lecture.

Just do it.

Active learning is a philosophy and approach in which teaching moves beyond the ‘podium-style’ lecture and directly includes students in the learning process. There is certainly a big movement out there to include active learning in the classroom, there is evidence that it works, and active learning strategies have been around for a long time. Active learning can make learning experience more interactive, inclusive, and help embrace different learning styles. Active learning places the student in a more central role in a classroom, and allows students to engage with the course and course content in a different way.

So, why doesn’t everyone embrace active learning?

Without a doubt, it can take a bit of extra work. This post by Meghan Duffy provides an excellent case study, and illustrates the benefits and drawbacks of embracing a ‘flipped classroom’ in a large biology class, and part of that involves heaps of active learning strategies.

Active learning also involves some risk-taking, and perhaps risks that pre-tenure instructors should avoid. The strategies can remove some of the control of the instructor, and this can be uncomfortable for some teachers. For any active learning strategies to work, the instructor, and students, need to be on board, and each strategy brings some challenges, takes time to prepare, and certainly takes time in the classroom.

This term, in my 70+ student ecology class, I decided to take the active learning challenge, and, every lecture, include active learning*. I want to share a few of the things I have done so far, and hopefully show that some ideas are easy and doable, for pretty much any teaching context (note: I do use this book to help generate ideas)

1) The teacher becomes the student: for the last five minutes of class, I pretended to be a student, and asked the students to become the teacher. I then asked them some questions about the course content, drawing upon material from the last couple of lectures. Because I have taught the course for many years, I had a good sense of where some ‘problem areas’ may be, and thus formulated questions that got to the more difficult material. Students then were able to respond to my questions, and share their own expertise with the whole class.

2) Clear and muddy: at the end of one lecture, I asked the students to write down one part of the content they really understood well (the clear), and one area that might be “the muddiest point” (i.e., what they are struggling with). Students handed in the pieces of paper, and I went through and sorted them, and then spent part of the next lecture re-explaining common muddy areas. This was a terrific way to get anonymous feedback, helped reinforce areas that I perceived to be going well, and allowed me to target problem areas in the course.

Here's a "muddy" - this student's comment reflects a common concern around how I teach some of the content.

Here’s a “muddy” – this student’s comment reflects a common concern around how I teach some of the content.

3) Gather in groups: many active learning strategies work best when students are in groups. To quickly set up groups during class, each student holds a ‘card’ with different symbols, letters, numbers, and drawings, and when I call out one of these, the students form groups. I made the cards so students get sorted into groups of different sizes, depending on the activity.

 

Cards given to students, for quick abilities to arrange into groups.

Cards given to students, for quick abilities to arrange into groups.

An easy and effective active learning strategy with groups is to have student discuss among themselves a particular problem or question. After a few minutes, a spokesperson can report back their findings to the whole class. I’ve also had some students come to the front and present the result to the class. This does depend on having ‘enthusiastic’ volunteers, but I have not found this a barrier.

4) IF-AT cards: this term, I am trying to use Instant-feedback assessment-techniques for multiple choice questions. These cards allow students to scratch off answers on a card, and they immediately know if they are right and wrong, and can scratch a second or third time to receive partial points. I have used these in the classroom, for group work, and then students can work on problems (presented by me on the blackboard or screen), debate and discuss the answers, and then scratch off to reveal the correct answer. This activity therefore includes group work, problem solving, discussion and debate, and instant feedback. It does take a little bit of time (20 minutes or so, for a few questions), but is an effective active learning strategy that combines learning with an instant-feedback style of assessment.

5) Pair and share: this is also a simple and effective way to get discussions happening in lecture. I pose a question or idea, and simply have students turn to their neighbour to discuss the answer. I then ask some of the pairs to share their answers or ideas, and I also divide the lecture hall into different sections and ask pairs from each section to report back. This allows full use of the space in the classroom and students at the backs, fronts, or sides are able to feel included.

All of the abovementioned strategies don’t actually take that long and do not require a major overhaul to the course or course content. I believe they are relatively risk-free and easy, and suitable for any instructor, pre-tenure or not. I see these kinds of active learning strategies more as ‘value added’ activities, and as small steps that can increase student engagement in the classroom.

I also teach with chalk, as I find that's a great way to make the classroom more active, for everyone.

I also teach with chalk, as I find that’s a great way to make the classroom more active, for everyone.

 

——–

* Full disclosure: so far I have succeeded in all but one lecture, and I’m eleven lectures in. I’ll post an update at the end of term, to let you know if I’m successful all term!

Trophic cascades in fragmented forests

Many birds eat insects and spiders. Some of these insects and spider are themselves predators, feeding on critters lower down in the food web. Some of the insects that are fed upon by birds, or other predators, also play important roles in forest, such as munching upon the fresh, green leaves of young trees (here’s a reminder).

Munch, munch, munch. The hungry caterpillar. (photo by Sean McCann, reproduced here with permission)

Munch, munch, munch. The hungry caterpillar. (photo by Sean McCann, reproduced here with permission)

These interactions are ongoing, all the time, in forests around the world. These forests, however, are changing in important ways. Some of them are getting smaller and smaller as humans continue to encroach on the land, via urbanization or agriculture. This results in a ‘fragmented’ landscape. A landscape with small forest patches, perhaps no bigger than your back yard. A landscape with larger forests, perhaps one in which you could get lost in. These forests are themselves connected to each other –sometimes directly by a corridor or hedgerow.

This is the context for PhD student Dorothy Maguire’s research. Within that context, Dorothy tackled a fascinating project, one that was just recently published. In this work, Dorothy and co-authors (including me, an undergrad at that time, Thomas Nicole, and McGill Professor Elena Bennett) put cages around small trees in different types of forests SW of Montreal. The cages (made of chicken wire) were in place to test the effects of ‘predator exclusions’ on the insects and spiders occurring on saplings. The prediction is that if you exclude larger predators, such as birds, this may allow a ‘release’ of other insects and spiders. In turn, this release may have trickle-down effects on an important process occurring in young trees: herbivory. For example, if a predator is more common because it’s not being eaten by birds, perhaps it will eat more caterpillars, which may mean the leaves on trees will be eaten less frequently. In ecology this is dubbed a ‘trophic cascade’. Dorothy did this work in the context of fragmented forests, and she worked in forests that were either small and isolated from other forests, or in forests that were large and connected to other forests. This was done because there’s an expectation that these ecological effects will be different depending on the degree of fragmentation happening on the landscape. For example, insectivorous birds may decrease in abundance in small, isolated patches, which means their effects on insect prey (and perhaps herbivory) may be reduced relative to effects in larger patches of forest.

Dorothy Maguire, working in a forest fragment.

Dorothy Maguire, working in a forest fragment.

During one summer field season, Dorothy and Thomas wrapped up some small sugar maple trees in chicken wire, left some alone as controls, counted insects and spiders over the summer months, and measured herbivory on the trees themselves. As expected, the effects of the ‘cage’ was significant: when you put a cage around a tree, you end up with more arthropods living on those trees. This confirms other papers which report a similar effect: insectivorous birds (and perhaps other vertebrate predators) have a significant, and meaningful impact on the insects and spiders living on trees. Or, stated another way, birds eat critters living on trees, and without these birds, there would certainly be more arthropods around!

Dorothy did not uncover a strong effect on the process of insect herbivory: although more insects and spiders were living in the trees protected by chicken wire, the leaves themselves were not affected. This could be because more insect predators were around, and thus compensating for the lack of birds, and eating just as many herbivorious insects (e.g., caterpillars) as the birds might have eaten.

The lanscape of southern Quebec. Lots of agriculture, some patches of forest.

The lanscape of southern Quebec. Lots of agriculture, some patches of forest.

Scaling up to the landscape context, there were no overall significant effects of the cage treatments in relation to the forest type, nor was the level of herbivory dependent on the landscape context. The general results for large, connected patches were no different than for small, isolated patches. However, the magnitude of the effect was marginally affected by the landscape context for the cage exclusion: vertebrate predator may have a more significant impact in smaller, isolated patches.

As with all research projects, this work resulted with as many questions as answers, which is equally frustrating and fascinating. It’s clear that vertebrate predators are important in these systems, but more work is needed to fully assess whether these effects are truly affected by the degree of forest fragmentation on the landscape. The lack of effects on the process of herbivory itself was equally intriguing – there are clearly many complex interactions occurring on small maple trees. Some of these interactions involve top-down predation events, but there are likely a suite of ‘bottom-up’ effects that are also influencing the system.

Reference:

MAGUIRE, D. Y., NICOLE, T., BUDDLE, C. M. and BENNETT, E. M. (2014), Effect of fragmentation on predation pressure of insect herbivores in a north temperate deciduous forest ecosystem. Ecological Entomology. doi: 10.1111/een.12166

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!