Worried Woolly Bears

 Photo by Tony Fischer. Wooly Bear Caterpiallar to Tiger Moth. CC. https://flic.kr/p/5DzVRB


Photo by Tony Fischer. Wooly Bear Caterpiallar to Tiger Moth. CC. https://flic.kr/p/5DzVRB

While biking to school these days I’ve had to dodge the fuzzy black and orange caterpillars scurrying across the bike path. What are these critters, and why are they running so fast?

Child stars

Apparently woolly bears are the most recognizable caterpillar in North America, which is funny because I had never heard of them until this year. They’re much more famous than their adult form, the Isabella tiger moth, or Pyrrharctic isabella for you Latin fans. That’s probably because the moth is nocturnal and a dull yellow-tan. The fuzzy orange-and-black caterpillars are more noticeable, especially with their habit of crossing roads on sunny fall days.

woollybear4

The real reason for the woolly bear’s fame isn’t its cute black head or its orange and black fuzz. It’s because early North American settlers thought the native caterpillars could predict the winter weather. The wider the orange stripe, the milder the winter would be. They were basically a fall version of Groundhog Day.

This seems silly to us now, but in an era where your survival depended on how much food you stored up the fall, any information these settlers had about the winter would have been comforting.

Scientists aren’t really sure why some caterpillars have wider stripes than others. It could be climate, natural variety in the population, or something that changes as a caterpillar grows. Woolly bears may not predict the weather, but they are awesome for a lot of other reasons.

Autumn angst

Photo by D.Fletcher. Wooly Bear. CC. https://flic.kr/p/sjk7A

Photo by D.Fletcher. Wooly Bear. CC. https://flic.kr/p/sjk7A

People usually see woolly bears in the fall when they’re in a hurry. They’re looking for somewhere to wait out the winter, and if they don’t rush, they’ll freeze. Well, they freeze anyway, but more on that later.

In the spring and summer woolly bears are solitary beasts. Native to southern Canada, they spend their days in meadows and fields hidden in patches of wildflowers. They’ll eat just about anything, from grass to maple leaves to dandelions.

But when winter rolls around they need to find logs, rocks, or tree bark to hide under, none of which are plentiful in wildflower meadows. So in the fall they wander out of their meadows and into more forested areas, which is why we see them crossing roads and bike paths. They’re just looking for somewhere cozy to wait out the winter.

Fuzzy popsicles

Over the winter woolly bears freeze solid. Starting with their heart. Think about how that would feel for a moment. Freezing is usually a supremely bad idea for a living thing. Water expands as it freezes, and prickly ice crystals damage cells and tissues. But woolly bears make a natural antifreeze called cryoprotectant, which keeps their bodies largely undamaged from freeze and thaw cycles.

If it warms up enough during the winter, the caterpillars might thaw and walk around a bit before refreezing again when it gets cold. However, just because they’re full of antifreeze doesn’t make them superheroes. Freezing and thawing multiple times over the winter increases their chances of death and organ damage. When it warms up in the spring, the caterpillars wake up and continue to eat before making a cocoon and transforming into a less-famous adult moth.

Why so hairy?

Woolly Bear fuzz close up. Photo by LadyDragonflyCC->;<. Woolly Bear close up. CC. https://flic.kr/p/7X2AYD/p/oBBdcR

Soft and squishy caterpillars are the ideal snack for birds, rodents, frogs and snakes. The woolly bear has a few ways to keep from becoming their next meal. First, they can run away pretty quickly. They will also curl up into a ball and play dead, keeping all their hairy bristles called setae on the outside. These setae do discourage some predators, but skunks and a few other animals have been known to roll them off before chowing down. It’s also thought that the hairs act as insulation during the caterpillar’s long winter’s nap.

Heal thyself

Besides being surrounded by predators, some woolly bear caterpillars get eaten alive from the inside out. Parasitic flies lay their eggs inside the caterpillar’s body. After they hatch, the larvae munches on the woolly bear’s insides before exploding out of its side. Ick. A 2009 study at the University of Arizona found that woolly bears self-medicate on certain plants which cure the parasite. Caterpillars infected with parasites ate way more alkaloids than their non-infected peers. However, too many alkaloids are poisonous, so woolly bears have to balance poisoning themselves with getting eaten alive by fly babies. Not a fun choice.

So watch out for these speed demons on a road near you this fall, and please try not to squish them.


References

https://bioweb.uwlax.edu/bio210/s2013/clinton_kevi/adaptation.htm
https://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/woolly_bear.cfm
http://blogs.scientificamerican.com/budding-scientist/httpblogsscientificamericancombudding-scientist20110713adopting-a-caterpillar-and-other-adventures/
http://newt.phys.unsw.edu.au/~jw/cryoblurb.html
http://www.britannica.com/animal/woolly-bear
http://lancaster.unl.edu/feature/guess10_3.htm
http://web.extension.illinois.edu/dmp/palette/061015.html
http://news.nationalgeographic.com/news/2009/03/090313-self-medicating-caterpillars.html
https://bioweb.uwlax.edu/bio210/s2013/clinton_kevi/classification.htm
http://escarpmentfund.ca/blog/how-fuzzy-was-he/
http://eol.org/pages/863046/details
http://bugguide.net/node/view/539
http://pnwmoths.biol.wwu.edu/browse/family-erebidae/subfamily-arctiinae/tribe-arctiini/pyrrharctia/pyrrharctia-isabella/
http://www.silkmoths.bizland.com/spisabel.htm
http://extension.psu.edu/franklin/news/2012/wooly-bear-caterpillars-2013-purported-peerless-prognosticators

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8 things I didn’t know about native bees

Bees come in a rainbow of colours. Check out this shiny green sweat bee. Photo by Jim McCulloch, CC. Sweat bee on coral vine flower. https://www.flickr.com/photos/jim_mcculloch/2950920481/

Bees come in a rainbow of colours. Check out this shiny green sweat bee. Photo by Jim McCulloch, CC. Sweat bee on coral vine flower. https://www.flickr.com/photos/jim_mcculloch/2950920481/

I have a confession to make; I’m an insect geek.

And when it comes to social insects like bees and ants I’m even geekier than usual.

So when I learned that the Learning Garden at the University of Ottawa was holding a free workshop on insect identification, I jumped at the chance to learn more.

One of the coolest things we learned was how to tell the difference between flies and bees. You would think this would be easy, right? Bees are fuzzy with yellow and black stripes. Flies are black and shiny.

In fact, it isn’t that simple! Many of the native bee species in Canada look like tiny flies. Also, many fly species are camouflaged to look like bees so predators won’t mess with them. So how do you tell them apart? Well, look at the antennae. In most cases, flies have short, stubby antennae and bees have long, languorous ones.

Armed with this information, we stepped out into the University’s learning garden to find some insects. Now that I knew what I was looking for, I was amazed to see how many bees there were! They came in all shapes and sizes, from 2mm to 2cm. They also came in an exciting palette of colours, from black to grey to bright green! Even cooler, all these bees were native to Canada!

I first learned about native bees while writing an essay on the possible causes of the major honey bee deaths in North America. I learned that these unsung-heros do a great job of pollinating farmers crops for free! It’s sad that we aren’t taught more about them in school. So I did some reading, and here’s what I found out.

1. Everything you’ve been told about bees is a lie

Okay, that’s a bit of an exaggeration. It’s more like ‘everything you’ve been told about bees only applies to honey bees’.

Out of 19,000 bee species worldwide, most museums, science centres, schools and documentaries only talk about one: the European Honey bee. You know, the queen with thousands of female workers, the yellow and black-striped workers bringing back nectar and pollen to feed the larvae, the waggle dance to communicate where flowers are located. You’ve heard it all before.

And there’s a good reason to talk about them. European honey bees are commercially valuable. They were domesticated a long time ago to produce honey and pollinate crops. Without pollination, we wouldn’t have fruits like apples, tomatoes, cherries, pumpkins, strawberries or blueberries. In fact, we need pollinators for 1 out of every 3 mouthfuls of food we eat!

The European honeybee is so essential to agriculture that European settlers brought them to Canada. The European Honey bee is now a mainstay of the Canadian economy. However, there were bees in Canada already, around 730 species to be exact! And even though we don’t talk about them very much, they’re still here! For some crops, like blueberries, native bees are even better pollinators than honey bees.

2. They came from underground

Bees weren’t always cute and cuddly pollen-eaters. They used to eat meat! Yep, bees evolved from predatory digger wasps, which still exist today.

Why this drastic change from munching on other insects to sipping nectar? Well, it had everything to do with the arrival of flowering plants. Believe it or not, flowers didn’t exist until the Cretaceous period (1465-65 million years ago). This means that dinosaurs pre-date flowers. Can you imagine a world without flowers? Weird, huh? The evolution of flowers created a whole new food source, and bees, wasps, butterflies and moths evolved to eat it up. Maybe sipping nectar was easier than catching live prey!

3. All by myself…

Considering that honey bees are the poster child of the social insect, I was surprised to learn that most native bees in North America not social at all. They live by themselves, and are called solitary bees. Each female builds her own nest, lays her own eggs, and collects all her own pollen and nectar. Who needs hundreds of sisters when you can be independent?

What does a solitary bee’s life cycle look like? A female finds a male to mate with, then digs or finds a burrow to lay eggs in. She collects a huge ball of nectar and pollen, then lays an egg on top of it. When the egg hatches, the larvae feeds on the pollen, and in the fall becomes an adult. The adults hibernate through the winter to emerge in the spring.

4. Hives? No thanks.

Bee exiting a burrow. Photo by Rob Cruikshank, CC https://www.flickr.com/photos/84221353@N00/5713786629/

Bee exiting a burrow. Photo by Rob Cruikshank, CC https://www.flickr.com/photos/84221353@N00/5713786629/

Most solitary bees don’t live in fancy hives, but in holes in the ground. Yep, kind of like hobbits. 90% of native bee species lay their eggs in burrows in the ground.

Osima bees have by far the cutest homes. They like to nest in tiny spaces including snail shells, keyholes and even locks!

5. Busy bee? No, lazy bee.

Some bee species trick someone else into doing all the work for them. They lay their eggs in the nests of other bees, and avoid the work of collecting pollen and making a nest. This behaviour is called cleptoparastisitm. So much for busy bees!

6. Bumbling around

The fuzzy Bumble bee is indigenous to Canada. It’s the only bee that sticks around to feed its growing larvae. All other native bees hightail it out of there once the eggs are laid. In the wild, bumble bees also nest in the ground, but usually let someone else do the work. Holes in trees or abandoned rodent dens make a cozy nest. However, domesticated honey bees are managed using hives.

7. Picky, picky

Some Canadian bees are picky eaters. They only collect nectar and pollen from one kind of flower. They aren’t doing this to be difficult. They’re doing it because they have evolved to be perfectly suited to that flower. For example, the bee Melissodes desponsa only visits thistles. Ecologists call picky eaters ‘specialists’. Most Canadian bees are ‘generalists’ which means they can get food from many different kinds of flowers.

8. The extinction factor

Because of their sensitivity to environmental factors, some bee species are prone to extinction. This is especially true for specialists that only feed on one type of flower. If the flower disappears, they are in trouble. And it’s not just climate change that is causing their food to disappear. Many of the flowers we grow in our gardens come from Europe, and most native bees can’t use them for food.In addition, chemical pesticides meant for pesky insect will also kill bees.

Okay, enough doom and gloom. What can you do to help native bees? You can give them food by planting native wildflowers, or by waiting to mow those pesky ‘weeds’ until after they have flowered. You can give them places to live, by leaving bare patches of ground in your garden. You can even install woodblocks with holes drilled into them. These are called trap-nests, and will attract bees that like to live in pre-existing holes.

Want to learn more? Check out this user-friendly field guide to native pollinators by the David Suzuki Foundation. The photos are incredible!
http://www.davidsuzuki.org/issues/downloads/Pollinator_Guide_5pg.pdf

Oh, and I’ve also decided to open up my blog to comments. If you have comments, questions or suggestions for a post, feel free to post them!

Also, if you haven’t checked out my Art page, you might like it.

References
http://sci.waikato.ac.nz/evolution/plantEvolution.shtml
http://www.pollinationcanada.ca/index.php?k=358
http://www.biology.ualberta.ca/bsc/ejournal/pgs_03/pgs_03_main.html
http://www.beefriend.org/documents/Recommendations%20for%20Conservation%20of%20Pollinators%20on%20FarmlandFinal_DSC.pdf
http://www.gnb.ca/0171/10/0171100025-e.asp

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