Bog spiders: family composition and sex ratios

This is the second post by Honour’s undergraduate student Kamil Chatila-Amos – he has been busy working on identifying LOTS of spiders from bogs of northern Quebec. His first blog post introduced his project: this one gives a glimpse into the data…

My project is focused on studying spiders from bogs in the James Bay region of Quebec. Five bogs along the James Bay highway were sampled with pan traps every week for four sampling periods. In the full project I’m looking at how abiotic factors (i.e. pH, water table, latitude, etc.) and the plant community affect the arachnid community composition. For now, let’s look at how the spider families are distributed in these sites:

bogSpidersThe first thing that might strike you if you are familiar with the area and its spider fauna is that in 4 out of 5 sites, neither Lycosidae (wolf spiders) nor Linyphiidae (subfamily Erigoninae) are the most abundant family. Previous studies in similar habitats tend to find a much greater proportion of those two taxa (Aitchison-Benell 1994; Koponen 1994). All sites except the first have more Gnaphosids than Lycosids. However, the breakdown within families is very different. Whereas the Lycosids are represented by 19 species, there were only five species within the Gnaphosidae. Even more impressive is that one Gnaphosidae species represents 99% of the family. Indeed, Gnaphosa microps alone represents a fifth of all arachnids I collected.

I’ve come to like Gnaphosa microps a lot! The family Gnaphosidae is pretty easy to identify thanks to their long and separate spinnerets, colour and eye placement. Even the palps, which are unique to species, are fairly easy to recognize. It ranges in size from 5.4 – 7.1 millimeters which is a large enough size so it isn’t a hassle to manipulate.

Gnaphosa microps, seen from above. Photo from the Biodiversity Institute of Ontario through Barcode of Life Data Systems

Gnaphosa microps, seen from above. Photo from the Biodiversity Institute of Ontario through Barcode of Life Data Systems

Gnaphosa microps is by no means a star of the spider world but we still know a fair bit about it. It is a holarctic species meaning it can be found in almost all of the northern hemisphere, even as far as Turkey (Seyyar et al. 2008). It is usually found in in open boreal forests, alluvial meadows and bogs. A nocturnal species, it spends its days in a silk retreat under moss or debris and hunts at night by catching prey on the ground (Ovcharenko et al. 1992). Even though sampling has been done very near my sites and in similar habitats (Koponen 1994) I still haven’t found another study where it was the most abundant species.

Another interesting tidbit about this species is just how skewed their sex ratio is. According to my data, males outnumber females almost 10 to 1! Now this does not mean it is always like this in nature, this ratio can be explained by sexually dimorphic behavior. This means that the males would behave differently than females in a way that would increase their odds of falling into traps. Indeed, according to Vollrath and Parker (1992) spider species with sedentary females have smaller, roving males. And like their model predicts the G. microps males are a bit smaller than the females.

Sex ratio of Gnaphosa microps, collected in bogs

Sex ratio of Gnaphosa microps, collected in bogs


So what’s next? I still need to retrieve the COI barcode of all my species and that will be possible thanks to the University of Guelph’s Biodiversity Institute of Ontario. This is to make sure my identifications are indeed correct. As a first time spider taxonomist it’s great to be able to confirm my work in a way that still is not widely available. Today I received the plate in which I’ll load the spider tissue and I am amazed at how tiny it is. I guess they just need 2mm per spider but I still expected it to be much more impressive. Hopefully I don’t get any nasty surprises once the DNA data comes back, although some of those tiny Linyphiids did give me a pretty bad headache…



Aitchison-Benell CW. 1994. Bog Arachnids (Araneae, Opiliones) From Manitoba Taiga. Mem. Entomol. Soc. Canada 126:21–31.

Koponen S. 1994. Ground-living spiders, opilionids, and pseudoscorpions of peatlands in Quebec. Mem. Entomol. Soc. Canada 126:41–60.

Ovcharenko VI, Platnick NI, Sung T. 1992. A review of the North Asian ground spiders of the genus Gnaphosa (Araneae, Gnaphosidae). Bull. Am. Museum Nat. Hist. 212:1-92

Seyyar O, Ayyıldız N, Topçu A. 2008. Updated Checklist of Ground Spiders (Araneae: Gnaphosidae) of Turkey, with Zoogeographical and Faunistic Remarks. Entomol. News 119:509–520.

Vollrath F, Parker GA. 1992. Sexual dimorphism and distorted sex ratios in spiders. Nature 360:156–159.

Insect herbivory in fragmented forests: it’s complicated

I’m excited to announce a recent paper to come out of the lab, by former PhD student Dorothy Maguire, and with Dr. Elena Bennett. In this work, we studied the amount of insect herbivory in forest patches in southern Quebec: the patches themselves varied by degree of fragmentation (ie, small versus large patches) and by connectivity (ie, isolated patches, or connected to other forest patches). We studied herbivory on sugar maple trees, both in the understory and canopy, and at the edges of the patches. Our research is framed in the context of “ecosystem services” given that leaf damage by insects is a key ecological process in deciduous forests, and can affect the broader services that forest patches provide, from supporting biodiversity through to aesthetic value. Dorothy’s research was part of a larger project about ecosystem services and management in the Montérégie region of Quebec.



Dorothy Maguire sampling insects in the tree canopy (Photo by Alex Tran)

The work was tremendously demanding, as Dorothy had to select sites, and within each site sample herbivory at multiple locations, including the forest canopy (done with the “single rope technique). Dorothy returned to sites many times over the entire summer to be able to assess trends over time. Herbivory itself was estimated as damage to leaves, so after the field season was completed, thousands of leaves were assessed for damage. The entire process was repeated over two years. Yup: doing a PhD requires a suite of skills in the field and lab, and there is no shortage of mind-numbing work… Dedication is key!

As with most research, we had high hopes that the results would be clear, convincing, and support our initial predictions – we certainly expected that forest fragmentation and isolation in our study landscape would have a strong effect on herbivory – after all, our study forests varied dramatically in size and isolation, and herbivory is a common and important ecological process, and insect herbivores are known (from the literature) to be affected by fragmentation.



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


However, as with so much of ecological research, the results were not straightforward! “It’s complicated” become part of the message: patterns in herbivory were not consistent across years, and there were interactions between some of the landscape features and location within each patch. For example, canopies showed lower levels of herbivory compared to the understory, but only in isolated patches, and only in one of the study years! We also found that edges had less herbivory in connected patches, but only in the first year of the study. Herbivory also increased as the season progressed, which certainly makes biological sense.

So yes, it’s complicated. At first glance, the results may appear somewhat underwhelming, and the lack of a strong signal could be viewed as disappointing. However, we see it differently: we see it as more evidence that “context matters” a great deal in ecology. It’s important not to generalize about insect herbivory based on sampling a single season, or in only one part of a forest fragment. The story of insect herbivory in forest fragments can only be told if researchers look up to the canopy and out to the edges; the story is incomplete when viewed over a narrow time window. In the broader context of forest management and ecosystem services, we certainly have evidence to support the notion that herbivory is affected by the configuration of the landscape. But, when thinking about spatial scale and ecosystem processes, careful attention to patterns these processes “within” forest patches is certainly required.

We hope this work will inspire others to think a little differently about insect herbivory in forest fragments. Dorothy’s hard work certainly paid off, and although the story is complicated, it’s also immensely informative and interesting, and sheds light on how big landscapes relate to small insects eating sugar maple leaves.


Maguire et al. 2016: Within and among patch variability in patterns of insect herbivory across a fragmented forest landscape. PlosOne DOI: 10.1371/journal.pone.0150843


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.


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.

A Tangle of Opiliones

The results are in!! Last week I ran a poll to get help in picking the best name for a congregation of Opiliones (i.e., Daddy long-legs, Harvestmenpersons). HUNDREDS of you voted, but the clear winner, with just about 55% of the votes is…

“A Tangle of Opiliones”


A congregation of Opiliones (photo by D. Ringer, reproduced here under CC License 3.0)

This name was proposed by “Antnommer” on Twitter, and it is quite fitting. When thousands of Opiliones hang out together, it does indeed look like a full-on tangle of Arachnids.

Thanks, everyone, for participating in the poll, and helping to find a perfect collective noun for these astounding Arachinds.

Here are the poll results, for those interested:

PollResultsAnd some of the “other” suggestions:


Here’s another video to illustrate a rather fine tangle of Opiliones


What do you call a congregation of Opiliones? (Poll)

The Arachnid order Opiliones are interesting animals, although vastly understudied. In the English speaking world, they commonly known as Daddy long-legs, Harvestmenpersons, or Shepherd spiders. Opilio, in latin, refers to “shepherd”, and many temperate/northern species have exceedingly long-legs, perhaps in reference to Shepherds on stilts, watching their flocks. The name ‘harvest’ likely refers to the natural history of some species who tend to see higher population numbers in the autumn (‘harvest’ season in the north). Many species are also known to form very dense ‘congregations’, sometimes numbering in the thousands.


A congregation of Opiliones (photo by D. Ringer, reproduced here under CC License 3.0)

I was doing a bit of art on the weekend, and was drawing such a congregation, and this led me to consider what to call a collection of Opiliones. There are great sites out there devoted to Animal Congregations, but none of them had a collective noun for Opiliones (spiders, by the way, are sometimes referred to as a clutter or cluster)

Time to change that. After some Twitter discussions, I present to you a Poll, and I am looking for your votes!


A congregation of Opiliones.

A congregation of Opiliones.

I’ll leave this Poll open until around the 8 of March – and then write an update! Please share!

…for inspiration, here’s a video for you:

Spiderday (#25) – February

It’s that time again! Spiderday – your monthly linkfest of all the best Arachnid stories from the past month.  Let’s get started…

A wolf spider. This photo by Sean McCann related to some daydreaming I've been doing, about collecting spiders.

A wolf spider (genus Rabidosa). This photo by Sean McCann related to some daydreaming I’ve been doing, about collecting spiders.



The Arachnophile: hunting the wolf


A wolf in the genus Rabidosa (photo by Sean McCann)


Hunting the wolf


In summer’s forest.

Armed with hand lens,

Forceps, vials, eyes and field book.

Up. Down. Under rocks, leaves, rotten logs.

Just look.

Behold! Scurry, pause, dash, dart.

Find that dark place.

All in eights: all is right.

Pedipalps and spinnerets; chelicerae and pedicel.

Chevrons? Eye shine? Perhaps a sac of treasures?

Pardosa, Trochosa, or Rabidosa?

Envisioning authors, keys, maps, habitus.

Line drawings come alive.

A marvelous wolf, hunted.

What a find! The Arachnophile’s delight!

Into the vial, destined for deep freeze.

Wait, think, imagine.

It is precious.

Not Tolkien’s monsters, or a reclusive terror.

It is Anansi, Charlotte, and Darwin’s gossamer.

Nature and natural.

History beyond our own.

Preserve? Conserve? Observe?

Catch, release, smile.


Agelenopsis webs

A hot, humid summer forest, with evidence of spiders.



1) The Lycosidae are impressive spiders, and go by the common name of “wolf spiders”. Here are some facts about wolf spiders.

2) This was inspired by daydreaming. Winter can be long and I’ve been thinking a lot about summer field work, and collecting arachnids in a hot, humid forest. I’ve been thinking about observing, collecting, preserving specimens. Bringing specimens back to a lab isn’t always necessarily. Sometimes watching is enough.