Frozen spiders

Winter has arrived here in the Montreal area. Brrrrrr. Last night was below -25C, there’s a bitter wind, and about a foot of snow on the ground. I found my warm mitts and down jacket, but our arthropod friends don’t have this luxury! This time of year really gets me thinking about how spiders are handling the weather….

What do spiders do in the winter?

Some spiders don’t overwinter at all, and instead die at the end of the Fall, with their hardy egg cases doing the overwintering. Many other spiders, however,  do remain active under the snow, in a little zone called the ‘subnivean zone‘ – between the snow and the ground. Others hunker down, nestled in leaf litter, under bark, or in otherwise concealed locations. On slightly warmer winter days, spiders can also become quite active on the snow surface. But all of this is generally not enough to guarantee survival, because even subnivean zones and hidey-holes can get very cold.

Maybe they freeze, and come back to life after it warms up? You may be inclined to think so – it certainly happens with a lot of insects. And, check out this photo that popped up on Twitter a week or so ago, by Nash Turley. It shows a fishing spider under a layer of thin ice, and it was still alive after Nash helped it out of its icy tomb. What the heck?

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A fishing spider, under ice.

Did this spider  ‘flash freeze’, and like a good science fiction movie, pop back to life once it warmed up?

Probably not… I think ‘flash frozen’ spiders probably won’t survive. The literature generally suggests that spiders are not freeze tolerant. In other words, their tissues cannot survive the process of freezing, and ice will cause irreparable damage. Instead, I suspect Nash’s spider was already prepared or preparing for winter, and got trapped under the ice, but hadn’t yet frozen. It’s physiological adaptations involve some nifty and super-cool tricks.

Spiders are generally thought to be freeze avoidant* (e.g. here’s a paper on this), and through the process of accumulating glycols in their blood (i.e., antifreeze), are able to supercool. This means their tissues remain unfrozen at temperatures well below freezing, because they have physiologically adapted via the production of special antifreeze compounds that stops them from turning into ice. It’s a neat trick, and one that is relatively common in the invertebrate world. Of course, supercooling alone doesn’t ensure survival at extremely cold temperatures, and that’s where other adaptations come into play. Spiders will therefore find their way to the relatively insulated subnivean zone, or deep down in soil or leaf-litter. These behavioural adaptations (i.e., selecting overwintering sites), combined with supercooling superpowers, helps them get through the cold seasons. 

For me, I’ll stick to my down jacket, and enjoy how Hydro Quebec helps keep our buildings warm!
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* actually, we don’t know nearly enough about spiders and their overwintering physiology. I should state that I assume most spiders are freeze avoidant, based on the current literature on the topic – there’s a LOT more species to study, though!

Spiderday (#23) – Happy Holidays

SPIDERDAY is finally back – it’s been a few weeks, but the end of the term has been hectic. However, it’s time to catch up on some great Arachnid-themed links from the last little while.

This will also be my last post of 2015, so I’ll also take this opportunity to THANK YOU for reading and commenting on this blog. I also wish everyone a Happy Holidays! Arthropod Ecology will certainly keep on truckin’ in 2016.

Here's looking at you... A close up of an Araneidae, from Insects Unlocked.

Here’s looking at you… A close up of an Araneidae, from Insects Unlocked.

Collectors cards, Arachnid style.

Collectors cards, Arachnid style.

Questions and answers about spiders

Spiders, spiders, everywhere. I get asked a LOT of questions about spiders – from students, friends, neighbors, over twitter, and from journalists. I recently spent some time talking to a journalist in my hometown about spiders in Quebec*, and thought to share the details here! Here’s a copy of some of the Q&A with the journalist:

A beautiful dock spider (photo by Sean McCann)

A beautiful dock spider (photo by Sean McCann)

Q1) Why your obvious fascination with spiders?

Spiders are fascinating because they have remarkable biology and life history, and are certainly as beautiful as all other animals. They are the top predators in their own world, feeding on insects that may cause economic damage to our crops, or catching mosquitoes that seek us out for a blood meal. They build stunning webs, have remarkable diversity of body types and the live almost everywhere on the planet (all terrestrial parts, except the Antarctic). As babies the ‘balloon’ up into the air, and are among the best dispersers in the world – better than many flying insects. They are among the most common animals in ecosystems – we have recorded, for example, that wolf spiders occur in densities of over 1 spider per square m in parts of the Arctic tundra. What’s not to love?

Q2) How long have you been interested in them and why do you think they have a bad rap with so many people ?

I became interested in spiders when I was doing my undergraduate degree at the University of Guelph. A botany Professor there was working on the old cedar trees growing off the cliff faces of the Niagara escarpment, and during one summer he hired me to help with that work. While hanging off cliff faces, I couldn’t help but notice SO MANY SPIDERS and this piqued my curiosity, Professor Larson then allowed me to do a research project in the lab, and I did that project on spiders. Like to many things … a little knowledge is a dangerous thing. As I learned more, I became more and more fascinated by Arachnids, and continued on to do another undergraduate research project on spiders, and it just continued and continued until this day. I have been working with spiders now for over 20 years of my life.

Arachnophobia is real and serious for many people, but in many cases, people are not necessary arachnophobic, but rather have a general (unfounded) loathing for spiders and I believe this is largely because they have not explored their incredible biology and natural history. With education, I find people can shift from fear to curiosity and amazement. There have been studies done that illustrate that the ways that spiders move, and their extra legs, may contribute to a general fear of spiders – in other words, they can surprise us and are so “Leggy” that it causes a startle reaction and this perhaps leads to fear. This is very common in our society, and this feeds a cycle of fear, as our children learn fears from us. There may be some genetic basis to being afraid of spiders, also, and this probably relates to the fact that some spiders are indeed venomous to humans. In this part of the world, however, there are very few spiders of medical importance, and spider bites are exceedingly rare. Although everyone has a story about a spider bite, most of these are not verified, and other more likely causes should be investigated. Misdiagnosis is common in the medical field, also.

Q3) Why are they beneficial in the garden? And, even in moderation I assume, in the home ?

Spiders are beneficial because they eat many insects that themselves can be harmful to our gardens. In our homes they also feed on other insects that live in our homes. Without spiders, we would certainly have more other critters in our house and garden.

A cellar spider, with prey (c) A. Bradford

A cellar spider, with prey (c) A. Bradford

Q4) How many types of spiders do you think we have in this region and what would you estimate their total population to be?

There are over 40,000 different species of spiders in the world, over 3,000 species known in Canada, and over 600 species known from Quebec. That is a LOT of different kinds of spiders! There are certainly more species of spiders in the world than there are mammals or birds. I estimate an average yard in any small town in southern parts of Canada harbour easily 20-30 different species, and our local forests certainly can have over 100 different species.

It’s difficult to estimate population (i.e., how many of each kind of spider), but it’s fair to say that the old saying that you are always within three feet of spider is likely quite accurate, at least when you are in natural environments. The sheer biomass and density of spiders in some parts of the world is truly astounding.

Q5) What are some of the most common kinds of spiders?  What do they do during the winter?

Common spiders in our homes include things like the “Zebra jumper” Salticus scenicus it’s the little black and white jumping spider that is common in our window sills or on the walls of our houses, especially on warm summer days. Many of us have the Cellar spiders Pholcus phalangioides in our houses (they have long, gangly legs, but are not to be confused with “Daddy long legs – aka Harvestmenpersons – they are cousins to spiders, but not actually spiders!). In our gardens in the late summer, we see many individuals of the black-and yellow garden spider Argiope aurantia – it’s very large, with black and yellow striping on its abdomen, stringing up its huge webs in our gardens. Another very common orb-weaving spider, that also matures in the late summer, is Neoscona crucifera. We often see funnel-web or grass spiders (Agelenopsis) on dewy mornings: they can build their sheet-webs (with a funnel retreat at one end) on shrubs or on our lawns, in very high densities – obvious with a heavy layer of dew. We also find Canada’s largest spider in southern Quebec – an impressive animal!

The cute Zebra jumper (By Alex Wild)

The cute and common Zebra jumper (By Alex Wild)

Spiders do various things in the winter – in some cases the egg cases overwinter, and in other cases the spiders overwinter. Most spiders are “freeze avoidant”, meaning that they cannot freeze without dying, so they often adapt by ‘supercooling’ which essentially means they produce antifreeze in their bodies so they will survive below freezing temperatures. Spiders generally find places to hide in the winter, whether it’s in leaf-litter, under rocks, or finding a way into our warm basements.

Q6) Do you have a personal favourite spider?  If so, why, and what is it called?

I really like the ant-mimicking jumping spiders such as Peckhamia pictata  – it occurs in Quebec, and is a marvellous mimic of ants – most people don’t notice it because it fools us by its shape and behaviour – and so very easy to mistake as an ant instead of a spider. There are, in the world, about 300 different species of jumping spiders that mimic ants – a behaviour that is more common in the tropics, but also happens with some species here in the north.

Q7) How long have spiders been around on Earth and how long do spiders, on average, live?

Spiders have been around for perhaps 400 million years, which is a very, very long time. They have been on this planet far longer than us!

In this part of the world, spiders typically live one year, although some larger species may take more than one year to reach adulthood. In captivity spiders can live a very long time – I have a Tarantula named Harriet, in my lab at McGill, and she is approaching 20 years old.

© C.M. Buddle (2015)

*indeed, this Q &A was Quebec-focused, so may not be generalizable to all parts of the world!

Spiderday (#22)

It’s been a couple of weeks, but nevertheless, here is another edition of SPIDERDAY! All the best Arachnid-themed links, pulled from the web in the last little while.

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

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Screen Shot 2015-11-20 at 9.25.57 AM

Spiderday (#21)

Spiderday! Here’s some Arachnid-themed links I stumbled across over the past week.

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.

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Spiderday (#19)

It’s been a few weeks since the last SPIDERDAY (sorry…). Here’s another edition of this feature, with links to some of my favourite stories about Arachnids. It was easy to pull this together this month, since it’s  Arachtober.

This is a lovely spider species in the family Titanoecidae. (Photo by Sean McCann)

This is a lovely spider species in the family Titanoecidae. (Photo by Sean McCann)

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Ctenus exlineae

Ctenus exlineae