Spiderday (#20)

What a great day. It’s Halloween AND spiderday. On the same day. And it’s the 20th edition of spiderday. It just doesn’t get any better.  Here are the arachnid-themed stories I pulled from the web over the past week.

But first… just LOOK AT THIS amazing little spider:

A mystery 'tube spider' by Daniel Llavaneras.

A ‘tube spider’ (genus Dipoena) by Daniel Llavaneras.


The natural history of teddy-bear solifugids: cuddly wonders of the desert

This post was written by Michael Kent, with minor edits from C. Buddle. Michael is a naturalist at Killbear Provincial Park. Both Chris and Mike are very devoted to continue to improve the public image of Arachnids. This post by Mike will surely help… 

More chelicera than cephalothorax, the Solifugae or “those who flee from the sun” look like a reckless arachnid bulldozer that could star in Mad Max. Otherwise known (incorrectly!) as camel spiders, whip scorpions, and my personal favourite baarskeerders (Afrikaans for beard cutters), solifugids are often one of the dominant arthropod predators in arid ecosystems. They ruthlessly chase, hunt, stalk, and scavenge using their leg-lengthed pedipalps to snatch prey while using their jaw-like chelicera and digestive juices to masticate their invertebrate and small vertebrate victims to a pulp.

Competing for one of the cutest arachnids is this Teddy Solifugae (Hexisopus sp.). Not just for petting, the fuzzy mat of hairs covering its body are mechanoreceptors capable of detecting miniscule changes in temperature, humidity, and air movement. Photo by M. Kent.

Competing for one of the cutest arachnids is this Teddy Solifugae (Hexisopus sp.). Not just for petting, the fuzzy mat of hairs covering its body are mechanoreceptors capable of detecting miniscule changes in temperature, humidity, and air movement. Photo by M. Kent.

Like most arachnids, solifugids don’t get much positive media attention. Famous on the internet by “forced perspective” photos makes them appear to be much larger and scarier than their modest 15cm maximum. There is even a photo of an intimidating, solifugid-like creature constructed by a talented invertebrate artist that has many fooled. As formidable as they look, they are likely non-venomous, with bites being rare and only resulting in localized pain and swelling in humans (Naskrecki, 2012).

When it comes to cuteness in the arachnid world, salticids are the reigning champions with their captivating eyes and fancy footwork. Normally ranking near the bottom, solifugids have a new challenger for the world’s cutest arachnid with the teddy bear solifugid family, the Hexisopodidae. Observed while on a trip to Namibia in January, this family is endemic to South Africa and look more like “baarskeerdlers” (beard cuddlers) rather than a baarskeerders. Surrounded by an arid lunar landscape, one was observed slowly waddling (extremely atypical for most solifugids) in the dry, sandy riverbed in a gorge in Damaraland.

Also known as mole solifugids, as soon as it sensed us, it buried itself beneath the sand and disappeared. A member of the family Hexisopodidae, it is characterized by adaptions to a mysterious subterranean lifestyle with fossorial 2nd, 3rd, and 4th legs, with the 4th lacking tarsal claws (Savary, 2009). Overall, not much is known about the life history of the Solifugid order other than some broad generalizations based on detailed observations of just a little more than a handful of different species.

Not meant for speed, solifugids in the Hexisopodidae family are equipped with fossorial 2nd, 3rd, and 4th legs. Photo by M. Kent

Not meant for speed, solifugids in the Hexisopodidae family are equipped with fossorial 2nd, 3rd, and 4th legs. Photo by M. Kent

From what we know solifugids typically only live one year or less, and burrowing is an important part of their life. When they’re not spastically running about searching for food, burrows serve as a daytime refuge providing proper humidity, a safe retreat from predators, or protecting during vulnerable times when molting, digesting, or depositing eggs (Wharton & Reddick, 2009). Eggs take anywhere from 2 days to 2 months to develop into larvae, dispersing at the 2nd instar, and going through 4-8 nymphal instars before becoming an adult (Wharton & Reddick, 2009). It is unknown whether the Hexisopodidae have similar life-history traits. How much time do they spend underground? Why do they go underground? Do they hunt for food by searching in the sand or ambushing?

One of only two known genera in the Hexisopodidae family – Chelypus and Hexisopus – can be morphologically distinguished from each other by the presence or absence of well-developed spines on the pedipalps. Photo by M. Kent.

Solifugae taxonomy is messier than a cobweb. Whether solifugids share a more recent common ancestor with pseudoscorpions or mites is still debated. They all share certain features of the mouthparts. Solifugae and acariform mites have a potential synapomorphy in their sejugal furrow, while solifugae and pseudoscorpions share several characters such as similar tracheal respiratory systems (Dunlop, & Penney, 2012). The solifugae Order consists of 12 families, 141 genera and 1095 described species (Savary, 2009). However, some families are too arbitrarily defined and lump genera, while others are too narrowly defined and split genera creating a phylogenetic cobweb. Revising solifugid systematics needs to start from the ground up.

Recently, a team of researchers funded by the American Museum of Natural History did just that and presented a comprehensive analysis of cheliceral morphology for Solifugae by taking high-res images of the jaws of 188 different species, comparing them with existing literature, and identify and reinterpreting structures based on primary homology. It is crucial to be on board with the same jaw terminology because it is an important morphological character set containing relevant information for identification and sexing (Bird et al. 2015)

Solifugids also share various other morphological characters including malleoli and suctorial organs. Chemosensory malleoli or racuquet organs located on the underside of their 4th pair of legs. Analogous to scorpion’s pectin, the series of fan-like structures is thought to play an important role in the detection of food, predators, and mates (Punzo, 2012). The suctorial organs located at the tip of the palps are used to apprehend potential prey and climb vertical surface. The latter was observed as a solifugae was observed clinging to a window near the Monteverde Cloud Forest in Costa Rica.

One of only a handlful of solifugid species found in wet, tropical environments. This solifugae was observed in the Monteverde Cloud Forest clinging to a window using its sutorial organs

One of only a handlful of solifugid species found in wet, tropical environments. This solifugae was observed in the Monteverde Cloud Forest clinging to a window using its sutorial organs. Photo by M. Kent.

Solifugids are even found in Canada! At the northern limit to their range, suitable semi-arid habitat is found in the coulees and badlands of Southern Alberta, in the cities of Lethbridge and Medicine Hat, Southern Okanagan Valley of BC, and a Southern Saskatchewan (Johnson, 2004).

Next time you are visiting arid parts of the world, do watch out for these fascinating Arachnids. They are worthy of our attention, especially since so much of their natural history remains unknown. Cuddle up to “baarskeerdlers”, and be amazed.

Text and photos © M. Kent (not to be reproduced without permission)

Equipped with the largest invertebrate jaws for its body size, solifugids don't need venom. They masticate their victims instead, relying on their huge head muscles to power their exoskeleton crunching chelicera. Photo by M. Kent.

Equipped with the largest invertebrate jaws for its body size, solifugids don’t need venom. They masticate their victims instead, relying on their huge head muscles to power their exoskeleton crunching chelicera. Photo by M. Kent.


Bird, T., Wharton, R., & Prendini, L. (2015). Cheliceral Morphology In Solifugae (Arachnida): Primary Homology, Terminology, And Character Survey. Bulletin of the American Museum of Natural History.

Dunlop, J. A., & Penney, D. (2012). Fossil Arachnids. Siri Scientific Press.

Johnson, D. (2004). Scorpions in Canada. Retrieved from University of Lethbridge: http://people.uleth.ca/~dan.johnson/htm/solpugids.htm

Naskrecki, P. (2012). Solifugids – arachnid teddybears (with big teeth). Retrieved from The Smaller Majority: http://thesmallermajority.com/2012/11/09/solifugids-arachnid-teddybears-with-big-teeth/

Punzo, F. (2012). The Biology of Camel-Spiders: Arachnida, Solifugae. Springer Science & Business Media.

Savary, W. (2009). Hexisopodidae. Retrieved from Homepage of The Arachnid Order Solifugae: http://www.solpugid.com/Hexisopodidae.htm

Wharton, R. A., & Reddick, K. (2009). Life History. Retrieved from The Arachnid Order Solifugae: http://www.solpugid.com/Life%20History.htm


We are in for a great month. It’s not October… it’s Arachtober. It’s a month to celebrate all things Arachnid, from photos, to blog posts and stories about our eight-legged friends. It’s a month to appreciate Arachnids for what they are: stunningly beautiful animals.

A beautiful long-jawed orb-weaver (image by Alex Wild, from "Insects Unlocked".

A beautiful long-jawed orb-weaver (image by Alex Wild, from “Insects Unlocked”.)

To get all set for Arachtober, here are some ways to get involved and to learn about spiders:

First, do check out Africa Gomez’s blog – she’s promised to do daily (yes, DAILY) posts about spiders. Yay!

Be sure to follow Catherine Scott – she is on a terrific campaign to help educate people about spiders, and calm down the nerves and assure folks that the spiders they find are *not* brown recluse spiders. 

This is Catherine Scott, wearing a t-shirt with an important message.

This is Catherine Scott, wearing a t-shirt with an important message.

Be sure to keep an eye on the Arachtober Flickr group. Amazing photos to be found there; this was the first place that Arachtober got started… members of that group tried to post new spider photos daily, throughout the month of October.

For other photos about arachnids, do check out work by Sam Martin, or Thomas Shahan, or Sean McCann, or Alex Wild, to name a few. Here’s an example of Sean’s work:


If you want to find other Archnologists on Twitter, here’s a Twitter List for you.

Want to learn more about Arachnology? Check out the American Arachnological Society, or the International Society of Arachnology. Here’s a more general post about what to do if you want to be an arachnologist.

Arachnology has a rich and fascinating history. The Biodiversity Heritage Library is a wonderful resource: here, you can look at old titles about spiders and on their Flickr page, view stunning plates from those old books and journals.

Have some interests in drawing spiders? Don’t forget to get the anatomy correct! Here’s a post from a 10 year-old who did it right:


Have a read through these great Arachtober posts from the past, from Bug Gwen.

Another great blog to check out, for wonderful spider natural history, comes from “Bug Eric”.

Have a spider and not sure what it is? Sometimes you can surf around on BugGuide and work towards an identification with that. It’s a great resource for Arachnophiles.

Arachtober ends with Halloween, of course. Perhaps viewing some movies featuring spiders is a fine idea.

Oh, and for Halloween, here’s how to make your 3D spider cake (um, too bad about the spider’s anatomy is all wrong. Sigh)

And, finally: SPIDER ROBOT (check around the 7:00 mark):

So, how else will you celebrate Arachtober? Share your thoughts in the comment section, below!

[As many of you know, I’ve been posting weekly with links to stories about arachnids, called “SPIDERDAY“. Given a busy travel schedule this month, Spiderday may be a bit ‘irregular’ – sorry!]

Ecology from geology

I recently asked a geologist* to come to speak to my field biology class. The course is about the “St Lawrence Lowlands“, and throughout the term we visit farms, forests, lakes and streams, and we do natural history research.

Why then, do I have a geologist come and speak to us?

A result of glacial till: it's now supporting biodiversity.

A result of glacial till: it’s now supporting biodiversity.

Ecology is built upon geology. This may seem obvious, but requires a deeper discussion: after hearing this guest lecture year after year, I no longer see my local landscape as some farm fields, patches of forests, and some big bodies of water**. I see lands and waters shaped by a history before our time. The local landscape is a product of past geological events. We have farm fields around the Montérégie because the Champlain Sea deposited its sediments and after it departed; what remained is a flat expanse, perfect for farming. As the sea departed, it left behind remnants of beaches still visible today, as the Plateau district of Montreal, or where apple orchards grow next to Mont St Hilaire. We have some slight elevation here and there because of sandy deposits left by the departure of the last great glacier that covered our land in the very recent past. That’s where we find great white pines, stretching up above the canopies of the deciduous trees. We have Mount Rigaud because of processes hundreds of millions of years ago: an igneous intrusion that happened long, long before the age of dinosaurs. More recent igneous intrusions created the Lachine rapids, historically important as this became a key place where First Nations people, and later Europeans, set up camp along their journey up or down the big river. This was the one of the birthplaces of Montreal.

Our landscape, and the ecology of our landscape, is built upon slow but incredible processes, and I think biologists don’t consider those processes as dynamic forces that are constantly influencing our current view of the world. Ecologists often think of time in scales of decades or centuries, and we spend considerable time looking at time frames that resonate with our own life spans (in contrast, evolutionary biologists and taxonomists look much further back, and are accustomed to time frames of ‘millions of years’. I think We need to meet in the middle a little more).

As field biologists, knowing the origin of those big rocks in the forest matters a great deal: glacial till from the past creates habitats today. Moss creeps on these ancient boulders; centipedes and spiders crawl underneath. Their ephemeral life depends on much longer time frames. It’s hard to imagine how to consider discussion land management or wildlife conservation in the region without appreciating how past geological events can either help or hinder the process. There’s a geological reason why soil development is slow in some parts of our local ecosystems; why the land may be rocky, and why it’s well-drained in some areas, and wet in others. This affects long-term planning around wildlife preserves, or housing developments. There’s good reason why Mont St Hilaire is a biosphere reserve, and how it’s flora and fauna will be different that what we find elsewhere in the St Lawrence Lowlands.

Hiking at Mont St Hilaire: there are so many reasons why it's a special place, including geology.

Hiking at Mont St Hilaire: there are so many reasons why it’s a special place, including geology.

The longer I spend living here and learning about my region’s natural history, the more I recognize the value of some knowledge about geology, and this is why I have a geologist give a guest lecture. The students also tell me, year after year, that they appreciate and value this perspective, and their understanding of this part of the world is enriched by a deeper discussion about ‘why’ the St Lawrence Lowlands exists as it does.

How often do ecological classes include discussion about geology? Perhaps not often enough.

*the geologist in question is Dr. George McCourt, who teaches often in the McGill School of Environment. I am immensely thankful for him taking time to teach us about his passion.

**when I commute to work, this is what I see: forests, field and lakes. Others in the St Lawrence Lowlands will have a different story, perhaps one that involves highrises and concrete.

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

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

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

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

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

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

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

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

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

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

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

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

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

The Arctic pseudoscorpion, Wyochernes asiaticus

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

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

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

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


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

© C.M. Buddle (2015)

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

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

A stretch of the Dempster Highway

A stretch of the Dempster Highway

This year’s expedition was focused on three projects:

1) Tiny, wonderful arachnids:

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

The Arctic pseudoscorpion, Wyochernes asiaticus

The Arctic pseudoscorpion, Wyochernes asiaticus

2) Northern food webs:

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

Shaun Turney, vacuuming the Tundra.

Shaun Turney, vacuuming the Tundra.

3) Thermal biology of wolf spiders

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

Searching for wolf spiders on the Tundra

Searching for wolf spiders on the Tundra

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

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

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

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

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


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

Spiderday (the ninth)

Here’s your ninth edition of SPIDERDAY! Some arachnid-related links from the past week.

Please note: I’m just heaving off to the Yukon for a couple of weeks of remote field work (it will involve arachnids!). Spiderday will likely return on 18 July.

Wow - this is a Thomisidae (crab spider) that's an ant-mimic. In Australia, of course. Photo by Alex Wild.

Wow – this is a Thomisidae (crab spider) that’s an ant-mimic. In Australia, of course. Photo by Alex Wild.

Screen Shot 2015-06-26 at 9.32.45 AM

  • Scorpions, anyone? How about GIANT ones. An amazing post with stunning images that you just won’t believe!
  • Some very handsome Opiliones (Harvestmen, or daddy-longlegs)
  • This is from a while ago, but worth another read. The fastest land animal (scaled to relative body size) is… a MITE!
  • Tips for tick safety. Worth a look.
  • Here’s a great technique that arachnophiles are sure to use!