Natural history of canopy-dwelling beetles: More than just ‘Fun Facts’

This is the second post by undergraduate student Jessica Turgeon – she’s doing an Honour’s project in the lab; here’s her first post that introduces the project.  Since that first post, Jessica has spent a LOT of time at the microscope, and has identified over 120 species of spiders and beetles from forest canopies and understory habitats.

Every species has a different story to tell and each one of these is equally interesting. I sometimes think about natural history as ‘fun facts’: something interesting about an organism (or species) to tell children so that they can appreciate nature. As my time at McGill progressed and my knowledge of the natural world deepened, I realized that the ‘fun facts’ are actually built upon a very strong scientific foundation, and can help us understand results of research projects. Natural history can sometimes be reduced to ‘fun facts’ but it’s a whole lot more than that!

The European Snout Beetle on a pin.

The European Snout Beetle on a pin.

I decided that perhaps I should look at the natural history of some of my species and maybe this would shed light on some patterns that I’m seeing within the data. The most abundant beetle species was Phyllobius oblongus (Curculionidae) with 69 individuals. Interestingly, we only collected this species in the first half of our sampling season and they were mainly collected on black maple and sugar maple trees. To try and understand why this is so, I turned to the species’ natural history, and to the literature.

These weevils tend to eat fresh leaf shoots and prefer the soft leaves found on maple trees. Once the maple’s leaves are fully-grown, P. oblongus moves on to plants with indeterminate growth, like raspberry bushes (Coyle et al. 2010). This corresponds exactly to our data: the beetles were found on our black and sugar maples during the beginning of summer and then they taper off as the season progressed!

Beetle data: the European Snout Beetle was only collected during the beginning of the season.

Beetle data: the European Snout Beetle was only collected during the beginning of the season.

To make this even more interesting, P. oblongus is an invasive species. Its common name is the European Snout Beetle and was accidentally introduced into North Eastern North America in the early 1900s. While most invasive species are a cause for concern, both the Canadian and American governments largely ignore this species. It may inflict some damage to trees but not enough to be worried about. They’re more annoying to researchers than anything since they congregate in the trees in large numbers!

The second most abundant beetle species in the collections was Glischrochilus sanguinolentus (Nitulidae). This species is native to Canada and rather abundant. Species in this genus are called sap beetles but this species in particular is more commonly called a picnic beetle. Large groups of G. sanguinolentus swarm to picnics since they are attracted to sweet food, which ruins the picnics. In nature, they feed on the sap produced by injured trees – hopefully not an indication that the trees we were climbing were damaged!

The natural histories of species open new doors to understanding how organisms live and interact with one another. I thought that it was strange that P. oblongus completely disappeared from my samples midway through the sampling season and its natural history explained why this was so. Picnic beetles eat the exuding sap of an injured tree so in the future I’ll be on the lookout so that I don’t accidentally climb a broken tree! So really, natural history is more than just ‘fun facts’; it helps us understand patterns and to better understand how our natural world works.

References

Coyle, D.R., Jordan, M.S. and Raffa, K.F., 2010. Host plant phenology affects performance of an invasive weevil, Phyllobius oblongus (Coleoptera: Curculionidae), in a northern hardwood forestEnvironmental entomology,39(5), pp.1539-1544

Evans, A.V., 2014. Beetles of eastern North America. Princeton University Press.

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Summer in the trees: Undergrad research on canopy spiders and beetles

Note: this post is written by undergraduate Honour’s student Jessica Turgeon, who is a member of the arthropod ecology laboratory. This post is part of the requirements for her project, and is an introduction to her research.

I’ve always been interested in nature and the environment but was never a big fan of insects. As time went on and I learned to appreciate all organisms big and small I realized that I didn’t really have a preferred “pet taxon” but rather was interested in ecology and community structure. I found others that my interests were shared with other members of the arthropod ecology lab, and I was able to start an Honour’s project in the lab earlier this fall.

Using a beat-sheet in the tree canopy, to collect arthropods

Using a beat-sheet in the tree canopy, to collect arthropods

I was given an opportunity to do an internship at Kenauk Nature, a 65,000-acre plot of land near Montebello, Quebec. This property is primarily used for the hunting and fishing industries, but they are branching into scientific research. Kenauk was keen to support three McGill interns to complete the Black Maple project, the pilot project for Kenauk Institute.

The Black Maple project revolves around black maples, since Kenauk is the only area in Quebec to have a black maple stand. The project consisted of three sub-projects, one for each intern and each project dealing with a different taxon. While the two other students worked on plants and birds, my project was about arthropods and their diversity in Kenauk. We wanted to characterise the community structures of beetles and spiders based on vertical stratification and tree species: this involved tree-climbing!

Jessica - getting ready to climb up!

Jessica – getting ready to climb up!

During the summer, I looked at abundance data and concluded that beetles were more abundant in the upper canopy and that spiders were more abundant in the understorey. This internship transitioned into my Honour’s project, where I plan to look at species richness and functional diversity to answer my questions on community assemblages. To my knowledge, this has never been done at Kenauk Nature and would provide great baseline data for the owners of the property.

We sampled in three sites, each containing three trees. Each site had one sugar maple (Acer saccharum), one black maple (Acer nigrum) and one American basswood (Tilia americana). Within each tree we sampled five times: twice in the understorey, once in the middle canopy and twice in the upper canopy. We also used two different types of traps: beat sheets, an active technique, and Lindgren funnels, a passive technique. Both trap types are specialized, with beating more tailored towards spiders and Lindgren funnels invented to collect beetles. When beating a branch, the arthropods fall on a 1m2 sheet and are then collected whereas Lindgren funnels are hung in a tree and passively collect arthropods that fly into it.

LindgrenFunnel

As part of our job, we learned how to use a single ropes climbing system, a one-person method of using ropes to climb a tree. All three interns caught on quickly and it easily became our favourite part of the job. However, we did have to sort through the samples, a job requirement that wasn’t nearly as fun as climbing trees. But this is what happens in ecology: you romp around in the woods to collect your data then spend time in the lab analysing them. It was nice to experience this first-hand and I must say, I liked it and am looking forward to future projects like this.

Now that the summer is over and collection is completed, I spend all of my free time in the lab identifying beetles and spiders. All of the beetles are identified and about half of the spiders are identified. From this work, Kenauk Nature can proudly say that the property supports 24 families representing 117 species of beetles! Once the Kenauk Institute officially launches, more rigorous research can be done to try and increase these numbers.

Learning Taxonomy... spider drawings (of male palps) help.

Learning Taxonomy… spider drawings (of male palps) help.

All in all, from the sampling in the summer to the identification in the lab, this has been a great experience. Here’s to hoping the second half of my honours project will be as equally fun and challenging as the first half was! Stay tuned for a blog post to be published in the spring of 2016: it will summarize the main results from this Honour’s project.

Monitoring northern biodiversity: picking the right trap for collecting beetles and spiders

Ecological monitoring is an important endeavour as we seek to understand the effects of environmental change on biodiversity. We need to benchmark the status of our fauna, and check-in on that fauna on a regular basis: in this way we can, for example, better understand how climate change might alter our earth systems. That’s kind of important.

A northern ground beetle, Elaphrus lapponicus. Photo by C. Ernst.

A northern ground beetle, Elaphrus lapponicus. Photo by C. Ernst.

With that backdrop, my lab was involved with a Northern Biodiversity Program a few years ago (a couple of related papers can be found here and here), with a goal of understanding the ecological structure of Arthropods of northern Canada. The project was meant to benchmark where we are now, and one outcome of the work is that we are able to think about a solid framework for ecological monitoring into the future.

A few weeks ago our group published a paper* on how to best monitor ground-dwelling beetles and spiders in northern Canada. The project resulted in over 30,000 beetles and spiders being collected, representing close to 800 species (that’s a LOT of diversity!). My former PhD student Crystal Ernst and MSc student Sarah Loboda looked at the relationship between the different traps we used for collecting these two taxa, to help provide guidelines for future ecological monitoring. For the project, we used both a traditional pitfall trap (essentially a white yogurt container stuck in the ground, with a roof/cover perched above it) and a yellow pan trap (a shallow yellow bowl, also sunk into the ground, but without a cover). Traps were placed in grids, in two different habitats (wet and “more wet”), across 12 sites spanning northern Canada, and in three major biomes (northern boreal, sub-Arctic, and Arctic).

Here’s a video showing pan traps being used in the tundra:

Both of the trap types we used are known to be great at collecting a range of taxa (including beetles and spiders), and since the project was meant to capture a wide array of critters, we used them both. Crystal, Sarah and I were curious whether, in retrospect, both traps were really necessary for beetles and spiders. Practically speaking, it was a lot of work to use multiple traps (and to process the samples afterwards), and we wanted to make recommendations for other researchers looking to monitor beetles and spiders in the north.

The story ends up being a bit complicated… In the high Arctic, if the goal is to best capture the diversity of beetles and spiders, sampling in multiple habitats is more important than using the two trap types. However, the results are different in the northern boreal sites: here, it’s important to have multiple trap types (i.e., the differences among traps were more noticeable) and the differences by habitat were less pronounced. Neither factor (trap type or habitat) was more important than the other when sampling in the subarctic. So, in hindsight, we can be very glad to have used both trap types! It was worth the effort, as characterizing the diversity of beetles and spiders depended on both sampling multiple habitats, and sampling with two trap types. There were enough differences to justify using two trap types, especially when sampling different habitats in different biomes. The interactions between trap types, habitats, and biomes was an unexpected yet important result.

Our results, however, are a little frustrating when thinking about recommendations for future monitoring. Using more than one trap type increases efforts, costs, and time, and these are always limited resources. We therefore recommend that future monitoring in the north, for beetles and spiders, could possibly be done with a trap that’s a mix between the two that we used: a yellow, roof-less pitfall trap. These traps would provide the best of both options: they are deeper than a pan trap (likely a good for collecting some Arthropods), but are yellow and without a cover (other features that are good for capturing many flying insects). These are actually very similar to a design that is already being used with a long-term ecological monitoring program in Greenland. We think they have it right**.

A yellow pitfall trap - the kind used in Greenland, and the one we recommend for future monitoring in Canada's Arctic.

A yellow pitfall trap – the kind used in Greenland, and the one we recommend for future monitoring in Canada’s Arctic.

In sum, this work is really a “methodological” study, which when viewed narrowly may not be that sexy. However, we are optimistic that this work will help guide future ecological monitoring programs in the north. We are faced with increased pressures on our environment, and a pressing need to effectively track these effects on our biodiversity. This requires sound methods that are feasible and provide us with a true picture of faunal diversity and community structure.

It looks to me like we can capture northern beetles and spiders quite efficiently with, um, yellow plastic beer cups. Cheers to that!

Reference

Ernst, C, S. Loboda and CM Buddle. 2015. Capturing Northern Biodiversity: diversity of arctic, subarctic and northern boreal beetles and spiders are affected by trap type and habitat. Insect Conservation and Diversity DOI: 10.1111/icad.12143

——

* The paper isn’t open access. One of the goals of this blog post is to share the results of this work even if everyone can’t access the paper directly. If you want a copy of the paper, please let me know and I’ll be happy to send it to you. I’m afraid I can’t publish all of our work in open access journals because I don’t have enough $ to afford high quality OA journals.

** The big caveat here is that a proper quantitative study that compares pan and and pitfall traps to the “yellow roof-less pitfall” traps is required. We believe it will be the best design, but belief does need to be backed up with data. Unfortunately these kind of trap-comparison papers aren’t usually high on the priority list.

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…

Expiscor (8 July 2013)

It’s full on summer in my part of the world! Great to have heat, humidity and fireflies giving a nice show. Here’s Expiscor for this week… some discoveries fished out from the past week, from spiders and insects, to art and flying bikes. Hope you enjoy!

  • Just look at this lovely spider! (photo by Chthoniid, reproduced here, with permission)

Screen Shot 2013-07-07 at 8.18.13 PM

  • So you think mosquitoes are bad in your backyard…?? Check out this photo from the Arctic (my experience agrees with this, by the way!)
Mosquitoes in the Arctic (photo by J. Krause, promoted by Amanda Koltz)

Mosquitoes in the Arctic (photo by J. Krause, tweeted by Amanda Koltz, reproduced here with permission)

  • Gosh it was a fun week on twitter, including a hilarious conversation about Odd Science Equipment – weird things that scientists use to get the job done. Here’s the storify of the hashtag, and there are a couple of other related posts over at Dynamic Ecology (here, and here)
  • And the tweet of the week goes to…. Avi Goldberg.  I love coffee, too.

Screen Shot 2013-07-07 at 8.23.17 PM

  • Another home run for Malcolm Campbell.  Here’s a quote from his latest postAs children, we make use of our human home bases – like mobile harbours – from which we venture out to investigate new surroundings or circumstances. They are also the safe harbours to which we return for comfort, support and reinforcement when we feel unsure, challenged, or threatened by what we have found
  • In honour of the Tour de France (my favourite sporting event to watch, despite the past problems), a game changer: a flying bicycle (thanks Matthew Cobb for that one!)
  • Some promotion for my PhD student Dorothy Maguire – here’s a neat video from Ecosystem Services Montreal, about her work on forest fragments, herbivory and insects. And yes, tree-climbing too!

Seasonality of Arctic Beetles

I’m excited to report on paper written by Crystal Ernst, PhD student in my lab, and well known as the “Bug Geek“. This paper is a product of the Northern Biodiversity Program (yes, it sure is great that the papers from this project are starting to appear!), and will be one of Crystal’s PhD thesis chapters. The paper is titled Seasonal patterns in the structure of epigeic beetle (Coleoptera) assemblages in two subarctic habitats in Nunavut, Canada

A very nice Arctic beetle! (photo by C. Ernst, reproduced here with permission)

A very nice Arctic beetle! (photo by C. Ernst, reproduced here with permission)

Here’s a plain-language summary of the work:

Although we often think of Arctic systems as cold and lifeless, Canada’s tundra habitats are home to a high diversity of arthropods (insects, spiders and their relatives). Beetles are important insects on the tundra – filling ecological roles as predators (feeding on other insects), herbivores (feeding on plants), mycophages (feeding on fungi), and necrophages (feeding on dead or decaying animals). In this research, we wanted to find out what happens to ground-dwelling Arctic beetles as a function of seasonality. We were curious about whether different species occurred at different times during the short Arctic summer, and whether the functions of the beetles changes over the summer. This is an important area of study because beetles perform important ecological functions, and knowing how these functions change over time may have broader implications for northern ecosystems. This is especially relevant in the Arctic since these systems have a short ‘active season’, and climate change is disproportionally affecting northern latitudes. If climate change alters an already short summer, what might happen to the beetles?

This research was done as part of the Northern Biodiversity Program (NBP) – a broad, integrative project about the diversity of insects and spiders across northern Canada. The NBP involved collecting samples at 12 sites in the Arctic, but at one of these sites (Kugluktuk, in Nunavut) we had an opportunity to do a more detailed collection over the entire summer of 2010. This involved setting out traps for the entire active season, from June through to August. These traps were plastic containers sunk into the ground – beetles that wander along the tundra fall unawares into these traps, which contain preservatives, and are trapped until a researcher collects the samples. Traps were placed in wet and (relatively) dry habitats so that we could compare the two habitats. After the collections were returned to our laboratory, the beetles were identified to species, counted, and the biomass of the beetles was estimated – biomass lets us determine what happens to the ‘amount of beetles’ on the tundra in addition to figuring out ‘how many’ (abundance) and ‘what kind’ (species) were in the traps. The beetles were also classified into their key ecological roles. The data were then compared as a function of when traps were serviced to let us assess what happens to beetles as a function of seasonality.

We collected over 2500 beetles, representing 50 different species – remarkably, 17 of these species represented new Territorial records. This means that 17 of the species that were identified had never before been recorded in all of Nunavut! Although many ecological functions were represented by the beetles we collected, most were predators. We documented that wet habitats had different kinds of beetle species than the drier tundra habitats, even though the actual number of species between the habitats did not differ. We also uncovered a seasonal affect on the functions of beetles in the system – as the season progressed, the beetles tended to be represented more by predators compared to earlier in the season, which was dominated by beetles representing a diversity of functions. The mean daily temperature also related to the seasonal change that was observed in the beetles.

PhD student Crystal Ernst, happily working on the Arctic tundra.

PhD student Crystal Ernst, happily working on the Arctic tundra.

This work is one of the first to carefully quantify how beetles change during short Arctic summers. We found a diverse assemblage of beetles, filling a range of ecological roles. These ecological roles, however, do not stay the same all summer long, and the shifts in the beetles were related to mean daily temperature. Given that Arctic systems will be significantly affected by climate change, this is worrisome – if temperatures increase, or become more variable, this may affect ecosystem functions that are mediated by beetles. This is more evidence supporting the need to track climate change in the Arctic, and play close attention to the small animals of the tundra.

Reference:

Ernst, C., & Buddle, C. (2013). Seasonal patterns in the structure of epigeic beetle (Coleoptera) assemblages in two subarctic habitats in Nunavut, Canada The Canadian Entomologist, 145 (02), 171-183 DOI: 10.4039/tce.2012.111

Arthropods in the tree-tops: Canopy ecology in Quebec (Part 2)

Part 1 of this series highlighted how our laboratory accesses the forest canopy.  This post is about our projects related to understanding patterns of Arthropod diversity in Quebec’s forest canopies.

I will first highlight some work done by my former PhD student Dr. Maxim Larrivée.   Max started in my lab at the exact time that I received the grant for the mobile lift platform, and he become an expert at this machine, and he proved to be an immensely talented student.  His project was focused on understanding the spatial patterns of spider diversity in three deciduous forest sites located within an hour drive of the Island of Montreal.  In the first part of his dissertation, Max collected almost 14,000 spiders representing 82 species (Larrivée  & Buddle 2009).  The spider fauna of the canopy was markedly different from the fauna from the understorey, and it is likely that different mechanisms structure the assemblages in the two habitats.

Overall fewer spiders and fewer spider species were found in the canopy compared to the understorey, but at a species-specific level, there were some spiders that seemed to have a preference for living in tree-tops.  For example, the lovely jumping spider (Salticidae) Hentzia mitrata was significantly more common in the canopy.   We were also most excited to document the species Mastophora hutchinsoni (Araneidae) in the canopy – this is the famous “bolas spider” and we believe our canopy record may be the most northern record for the species.  The Bolas spider hunts by swinging a strand of silk at its prey, and this strand has a “bolas” of sticky capture thread at the end.  This species is truly fascinating, and in our system, it is a species that likes the canopy.

Max demonstrating the methods of using a beat-sheet to collect spiders in the forest canopy. Here, he is about 25 m above the forest floor.

The follow-up work to this baseline study was focused on understanding dispersal potential of spiders in the canopy as compared to the dispersal potential of understorey species.  Most spiders in our system are small, so we predicated that their main mode of dispersal was via ballooning (i.e., releasing a small strand of silk and letting the wind carry the spider away).  We had also hypothesized that dispersal might be one of the mechanisms behind the aforementioned patterns community structure in the canopy compared to the understorey.  Max collected live spiders in the canopy and understorey and set them up in a wind-tunnel in the laboratory.  He then documented each species’ propensity to disperse by looking at the frequency by which they showed ‘tip-toe’ behaviour (a pre-ballooning condition).  In the paper resulting from this research, we reported that the spiders in our system do have high dispersal potential, but that this potential did not differ depending on whether the spider was collected in the canopy as compared to the understorey (Larrivee & Buddle 2011).   This was a fascinating area of study, and we are left with as many questions as we started with!   For example, if dispersal potential doesn’t differ between canopy and understorey species, what mechanism drives the differences in community structure between the two habitats?

Our laboratory has been studying beetles as well as spiders – although I am personally very interested in spiders, I do recognize the beauty of beetles, and their important ecological roles in virtually all ecosystems.  One of Max’s field assistants (Brianna Schroeder) was keen to complete a small project about beetles so she set Lindgren funnels in the canopy and in the understorey.  Over 170 species were collected, and once again, the fauna from the canopy was differentiated from that of the understorey (Schroeder et al. 2009).

Max up in the canopy crane!

Two other field assistants that worked with Max (Kristen Brochu and Katleen Robert) also worked on their own projects, and together with my colleague at McGill University (Prof. Terry Wheeler), we are close to finishing up a manuscript to describe more patterns of arthropod diversity as a function of vertical stratification in Quebec’s deciduous forests – this work includes beetles as well as flies (Diptera).  Although the responses are not the same for the different groups of insects, we are finding that both beetles and flies show vertical stratification in our study sites.

Stay tuned for Part 3, which will focus on ecological interactions occurring in the Canopy.