Common Pill Bug (Armadillidium vulgare)

It’s funny how sometimes the most common animals are the ones I know the least about. I know a fair bit about tenrecs, cheetahs and lyrebirds, but know next to nothing about pill-bugs. In fact, I’ve barely even thought about them, asides from when I played with them as a kid. But this blog is a place for people to learn about animals (me included), so let’s talk about pill-bugs!

Pill-bugs are crustaceans, like crabs and lobsters, and belong to the genus Armadillidium, which currently has 178 known species. That’s an awful lot of species to cover, so I’m going to focus on one of the most common, and the most studied, species: Armadillidium vulgare, otherwise known as the common pill-bug. Common pill-bugs originated in Europe, near the Mediterranean, but have since been introduced around the world, with particularly dense populations in the United States.

Pill-bugs require moist soil to survive, as they do not possess a waxy cuticle to prevent themselves from drying out. As well, pill-bugs breathe from psuedotrachea, a type of modified lung that must be moist to function. Humidity levels of around 50-60% or more are ideal for pill-bugs. They are most common in temperate or Mediterranean-like climates, and are often found under debris, such as logs, stones, or human waste.

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I think pill-bugs are kind of cute, what do you think? Image credit: Franco Folini via Wikipedia

Common pill-bugs are oval shaped, and have armour-like plates along their bodies. They are not overly large, reaching sizes of 18 millimetres. Most pill-bugs are darkly coloured, with some having spots along their backs that can be yellow, brown or red. Common pill-bugs have seven pairs of legs, and a single pair of antennae.

Pill-bugs have to constantly worry about drying out, so much of their behaviour is centred around conserving moisture. When humidity is high, pill-bugs move slowly, and when humidity drops, they start to move more quickly, to search out moister areas. They move almost twice as much during the summer than in winter, and tend to be more active during the night, when moisture loss is reduced. When temperatures get to be 20 to 30 degrees celsius, pill-bugs release pheromones that cause them to bunch together, which reduces the surface area of individuals in the group, meaning less moisture is lost.

Many of you probably know that pill-bugs curl into balls, but do you know why? There are two likely reasons, the first being that all the soft, squishy parts of pill-bugs are located under their shells, so by curling into a ball pill-bugs can protect their vulnerable parts. The second is that rolling up into a ball helps prevent moisture loss, and as we’ve seen, moisture conservation is of paramount importance to these little guys.

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A pill-bug unrolling from a defensive curl. Image credit: Franco Folini via Wikipedia 

Pill-bugs fall prey to a number of animals, including birds and arthropods. They are not entirely defenceless — in addition to their armour and their rolling-in-a-ball technique, pill-bugs can release nasty secretions when threatened. Unfortunately, pill-bugs’ defences only really work against small invertebrates, and birds will readily snatch these guys up. Also, a clever genus of ants have super long mandibles that can pry open a pill-bug when it’s curled in a ball.

Pill-bugs don’t have a particularly yummy diet — they feed on leaf litter and other decaying organic matter. They are, however, quite adaptable, able to survive for several months without food, and when food is scarce, readily switch to other sources of nutrients. Pill-bugs will eat the roots of plants, seeds, fruit, other pill bugs, and even their own poop.

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I had a lot of fun drawing this fella! 

The mating season in pill-bugs depends on the climate, with mating usually occurring in warmer times. Thus in regions with mild winters, mating can occur year round, while in other areas mating usually starts in the spring. Both male and female pill-bugs mate with multiple partners, and females can store sperm for up to a year. Pill-bugs moult regularly on a 29 day cycle, during which time the bugs cannot move or eat, and are extremely vulnerable. A special moulting cycle occurs in females, called the parturial moult. Mating can only occur during a female’s parturial moult, so males have to be prepared! Female pill-bugs retain their eggs in a pouch until they hatch, for about two to three months. The little pill-bugs stay in the pouch for a few days, and after moulting a few times, are independent from their mothers.

Hopefully by now you realize just how fascinating pill-bugs are, and have a greater appreciation for them. I certainly do! These are some awesome little insects (and they’re pretty cute!)

Purple Sea Star (Pisaster ochraceus)

One thing I absolutely loved to do as a kid was wander around rocky shores, looking for any form of life. I’d lift up whatever rocks I could to search for crabs, I’d run from tidal pool to tidal pool to peer at starfish and sea anemones. I love living in Ontario, but one thing I desperately miss is the ocean. So today I’m going to going to write about a species of sea star, to fully embrace my nostalgic mood.

Probably the most common starfish I encountered as a child were large purple ones. Unsurprisingly, these are known as purple sea stars, but confusingly are also known as ocher sea stars, since not all of them are purple. They can also be orange, yellow, red or brown. That being said, most of these guys are purple, so I’ll refer to them as purple sea stars. They have five legs, each of which can be from 10 to 25 cm long. Purple sea stars are covered in very small spines, which are no bigger than 2 mm in height.

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An example of some colour variants in purple sea stars. Image credit: D. Gordon E. Robertson

Purple sea stars live in the Pacific Ocean, from Alaska to California. Depthwise, they can be found from 90 m to the low-tide zone. They are commonly found along the coast, on mussel beds and rocky shores. Special suckers on their feet allow purple sea stars to cling to rocks with great force, so they can withstand violent waves.

Despite their harmless looks, purple sea stars are quite vicious eaters. They feed mainly on mussels, but will also eat chitons, limpets, snails, barnacles, and sea urchins. They will swallow their prey whole if they can, grabbing their meal with their tubular feet and then everting their stomach onto their prey. The digestive enzymes in the starfish’s stomachs will then liquify the victim, so it can be easily ingested.

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A purple sea star. Image credit: D. Gordon E. Robertson via Wikipedia

Mussels try and defend against starfish by clamping their shells together very tightly, but sea stars are patient hunters. Mussels need to open their shells slightly, both to breathe and to feed. The starfish then use their strong feet to pull the mussel shell further open, and insert part of their stomach into the shell, digesting the poor mussel inside. Purple sea stars have quite large appetites, with one sea star being able to eat eighty Californian mussels a year (a California mussel can reach lengths of 20 cm, so they aren’t small).

Purple sea stars breeding from May to July, with both sexes releasing gametes into the water. If all goes well, sperm and eggs meet in the ocean,  and the fertilized eggs can drift around until they hatch. Sea stars progress through a number of larval stages, and at this stage of their life the little starfish are filter feeders, relying on plankton to sustain them. Purple sea stars live to be at least four years of age, and may live much longer.

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I decided to try something a bit more abstract for this week’s drawing. I had fun with all the shapes!

Purple sea stars aren’t just pretty; they are an extremely important species. Thanks to their diet, purple sea stars help keep mussel populations under control. A loss of only a few purple sea stars leads to a drastic increase in mussel populations. When sea stars are present, the intertidal ecosystem is diverse, instead of becoming dominated by mussels. So next time you see a sea star, remember that they help keep our oceans wonderfully diverse!

Cover image source

Liguus Snail (genus Liguus)

Okay, I’ll admit it — I picked this week’s animal solely because it looked super fun to draw. When I think of brightly coloured, beautiful animals, snails don’t usually come to mind. But there’s a certain genus of snails, known as Liguus, that are well-known for their amazingly vivid shells.

There are currently five species of Liguus snail, though there are many subspecies classified under each species of Liguus. Originally some of the subspecies were thought to be completely different species because their shells were very different in colour, but it turns out these snails just have a lot of intraspecific variety in their shells. Liguus fasciatus alone is known to have more than 120 different colour varieties.

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Amazingly, all these shells are from the same species, Liguus fasciatus. Image credit: Henry A. Pilsbry via Wikipedia

Liguus snails are found in a relatively small range, with most species restricted to Cuba and Hispaniola. One species, Liguus fasciatus, is also found in southern Florida. Liguus snails are terrestrial, and spend most of their time in trees, and prefer trees that have smooth bark. I guess if you have to slime your way across a surface, you wouldn’t want it to be super rough.

Do you know what snails eat? I had never actually thought about it. Liguus snails feed on a tasty and nutritious diet of moss, fungi and algae. They forage for their meals on the trees they live on, scraping these lovely morsels off the bark. Sounds delicious, doesn’t it?

Liguus snails are fairly big for snails, with their average size being about four centimeters in length, though they can get up to six centimetres long. As I mentioned before, these snails are known for their magnificently coloured shells. One species, Liguus virgineus, is commonly known as the candy cane snail because its striped shell looks a lot like a a candy cane (in snail form). Though I’m not quite sure what flavour candy cane it would be…

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A candy cane snail, also known as Liguus virgineus. Image source

There is certainly a downside to having such colourful shells: people think they are pretty, so they collect them. Over-harvesting of Liguus snails have led to a decline in the species, and habitat destruction isn’t helping the problem. It is now illegal to collect Liguus shells, so hopefully that helps keep these guys around for a while.

And I must end on a bit of a shameful note: after picking these animals to write about so I could draw one, I have not been able to complete the piece in time for this post. Rather than put a substandard and rushed picture on here, I’ll leave you with this, and I promise to get the real picture up in the next few days!

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Update: Finished my art for the blog! I’m going to leave the Sorry Snail in there because he’s pretty cute, but here’s my finished candy cane snail:

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Monarch Butterfly (genus Danaus)

Monarch butterflies have got to be some of the most well-known butterflies in the world. I remember in grade one our class raised monarchs from caterpillars to adult butterflies, to learn about metamorphosis. I also recall a play we had to do around the same time where I was a butterfly, and my mom made me these ridiculously awesome wings out of cardboard that were way more impressive than anyone else’s in the class (most of them had silly store-bought wings). The point is, that at least for me, monarch butterflies have been fluttering around in my consciousness for pretty much as long as I can remember. So it’s about time I blogged about  them.

There are three species of monarch butterfly, the North American monarch, the South American monarch, and the Jamaican monarch. they are found mainly in North and South America, though they also live in Australia, New Zealand and other Pacific islands. Sometimes these pretty travellers appear in the UK, though they usually are there by accident. Monarchs are well-known for their epic migrations, in which millions of butterflies travel south to avoid chilly winters.

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Aren’t they beautiful? Photo credit: William Warby via Wikipedia

Butterfly populations west of the Rockies head down to California for the winter, while those in the east overwinter in Mexico. Those that head to Mexico travel up to 7,778 km to get to their wintering sites — quite an accomplishment for tiny butterflies! This migration is dependent on their being available plants along the route to feed the butterflies, as well as a number of climatic factors, including favourable tailwinds, appropriate temperatures, and low precipitation. If there is an early frost, the butterflies will die.

To try and boost their survival rate, monarchs enter diapause upon commencing migration. This lets the butterflies store essential nutrients needed for the long journey, such as lipids, proteins and carbohydrates. Mating and egg development is also suppressed while the butterflies are in diapause, so they can save all their sexual energy for the spring.

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Overwintering sites for monarch butterflies. That’s a lot of little flutterbys! Image credit: bfpage via Wikipedia 

Once the butterflies get to their overwintering sites, things don’t necessarily get easier. If it’s too hot in their roosting areas, the monarch will use up their fat reserves and die before spring comes. Warm temperatures can also stimulate the butterflies to leave the wintering site too early, meaning they will die on the migration back.

This is actually true for all migratory monarch butterflies — none of them survive the migration home. But the successful ones manage to breed before dying, so their descendants can complete the trip home. In fact, it takes four generations of butterflies for the monarchs to get back north.

Monarch butterflies are pretty recognizable with their bright orange and black wings. These bright colours advertise the monarch’s poisonous nature to predators — the butterflies contain toxic cardenolide aglycones, which they get from their diet of milkweed plants. Another orange-and-black butterfly that can be easily confused with the monarch is the viceroy, which was thought to mimic the monarch’s colouring to pretend to be toxic as well. It’s now thought that both butterflies are unpalatable, and that each mimics the other. Nature is confusing…

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I’ve been wanting to get into digital painting for a while, but I’m not very good at it. Still, practice can only help, so I forced myself to do my drawing for the week digitally, and I’m pretty happy with the result!

Most monarchs have wingspans between 8.9 and 10.2 cm wide. Migrant populations have much larger wings than resident populations, as the bigger wings help the butterflies survive their long journeys. Monarchs with larger wings are much more successful during migration.

In recent years, the number of monarchs at overwintering sites has declined. This is likely due to habitat loss, herbicide use and infection by parasites. Though they are not listed as endangered, if this decline continues these beautiful butterflies could be in serious trouble.

Cover image source: Kenneth Dwain Harrelson

American Lobster (Homarus americanus)

I’ve never been much of a fan of lobster meat. I like it for the first few bites, especially dipped in butter, but then the meat gets way too rich and I get sick of it. While I might not be a fan of the meat, I do think lobsters are pretty cool animals, and it’s about time I wrote about them on here.

There are lots of different species of lobster, but I’m going to focus on the American lobster, as it is the species most people are probably familiar with. American lobsters live off the east coast of North America, from Labrador to North Carolina. They can be found in shallow or deep water, though they are more common in deeper areas. Lobsters like rocky areas, where there are lots of places for them to hide. They are nocturnal, spending the day inside their burrows, and coming out at night to feed.

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The range of the American lobster. Image source: Wikipedia

American lobsters are the largest of all lobsters, and are also the owners of the title World’s Heaviest Arthropod. They can reach maximum lengths of 64 cm, and weigh over 20 kg. Most American lobsters are a greenish blue colour, but there are numerous colour morphs, such as bright blue, yellow, orange or albino. You might be familiar with bright red lobsters — but live lobsters are usually not that colour. The pigments that give lobsters their normal colour break down when they are boiled, resulting in the bright red, ready-to-eat colour.

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A blue lobster. The chances of finding one are about one in two million. Image credit: Dan Dorothy via Wikipedia

American lobsters have ten legs, four pairs of which are small used for moving. The fifth pair are the most fun, extending into great big claws that are supposed to have the juiciest meat. You may not have noticed when you were digging into a lobster, but the two claws are asymmetrical. One is bigger than the other, and has rounded bumps; the smaller claw has sharp, small teeth. The functions of the two claws are quite different: one is used for crushing (the bigger claw), and the other is used for cutting.

Lobsters start out as very small animals, weighing less than a tenth of gram upon hatching. They grow through a series of moults, which begin with the lobster reabsorbing the minerals that harden the shell. This makes the shell soft, so that the lobster can break through it. The softness of the shell also allows the lobster to take in water, which makes it swell in size. The new shell then hardens, and the moult is complete. A lobster can grow 10-15% in size during each moult. To reach the minimum legal catch size, American lobsters go through 25-27 moults.

Moulting serves another very important function for lobsters: females can only mate within 48 hours of a moult. The females lay their eggs between a month and fifteen months after fertilization. during this time, sperm is stored inside the females, and the eggs are fertilized as they leave the females’ bodies. Lobsters can lay between 3,000 and 75,000 eggs, depending on their body size. After the eggs have been laid, female lobsters carry them under their tails until hatching, for about ten to eleven months. The survival rate of young lobsters is very small, with only one in one thousand reaching the juvenile stage.

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A female lobster carrying eggs. Her tail is notched to mark her as a breeding female. Image source: Wikipedia

Though lobsters are a popular food animal, they are currently not threatened. This is in part due to the strict regulations that protect lobsters from overfishing. Lobsters under 8.3 cm must released, and in some areas lobsters over 13 cm cannot be caught, to keep breeding males alive. If a lobster is caught carrying eggs, a notch is put in her tail, and notched animals cannot be sold or caught. These regulations ensure a large breeding population, key to the survival of lobsters.

While there are many tragic stories about overfishing in our oceans, it seems like lobsters are doing pretty well, which is great news!

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A fun silhouette I did of a lobster! 

Cover image source: Wikipedia

Goldenrod Crab Spider (Misumena vatia)

I want to start off this post with announcement: Our Wild World will be switching to one post a week, on Wednesdays, instead of posts on Wednesdays and Sundays. Things have just gotten too busy for me to keep up with posts twice a week. This was originally supposed to be a weekly blog anyway, so things are just changing to how they were meant to be.

Now that that’s out of the way, we can talk about today’s animal, the goldenrod crab spider. Goldenrod crab spiders are found in the northern hemisphere, in North America and Europe. They are found on fences, leaves, and are especially fond of flowers.

Goldenrod spiders are the largest crab spider in North America, with females growing to be 10mm excluding their legs, and males reaching 5mm. Crab spiders are named because they somewhat resemble crabs, with wide, flat bodies and long front legs that are held open.

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A goldenrod crab spider, in its white form. Image credit: A1xjlq1 via Wikipedia

Goldenrod spiders vary in colour, depending on where they live. You see, crab spiders are ambush predators, waiting on flowers for prey to come swooping by. When an unfortunate insect chances by, the spider grabs their victim with their front legs, and then injects venom into the insect. They feed mainly on flies, butterflies, grasshoppers and bees.

Though goldenrod spiders hang out on lots of different types of flowers, the ones they most favour are goldenrods (no surprise there), trillium, and white fleabane. To camouflage themselves, goldenrod spiders are either bright yellow or white, sometimes with dark markings on the abdomen.

The spiders can change between the two colours, switching between yellow and white depending on the type of flower they are on. They switch colours by secreting a yellow pigment into the body, and excreting the pigment when they want to go from yellow to white. Once the pigment has been jettisoned, however, the spiders have to remake the yellow pigment, so it takes longer to transition from white to yellow (10-25 days) than from yellow to white (6 days). The spiders change colours based on what they see, as crab spiders who have had their eyes painted do not change colour to reflect the colour of flower they are on.

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A goldenrod crab spider using its excellent camouflage to catch a wasp. Image credit: Olaf Leillinger via Wikipedia

Crab spiders rely on their expert camouflage not only to catch prey, but also to avoid becoming prey themselves. Because they don’t try and actively avoid predators, crab spiders can focus on growing and reproducing. That’s why female crab spiders have such huge abdomens — and there is a direct correlation between female weight and egg clutch size, so bigger females do better reproductively.

I’m not a huge fan of spiders, and I have a lovely memory of a crab spider parking itself on my shirt when I was a child (it was a flowery shirt). But crab spiders as whole aren’t too bad. At least they are pretty colours and don’t looks as terrifying as some species of spider.

Now, I have another announcement to make: I have started a pet and wildlife portrait business! And I’ve decided to make my blog and my art work together, so from here onwards I will be making an art piece for every animal I write about on this site. Of course, this means I had to draw a spider, which was extremely difficult for me. But I did it!

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My drawing of a goldenrod crab spider, done in ink. 

Cover image source: Roqqy via Wikipedia