Invertebrates

Sanguivores: Nature's Blood Drinkers

Oxpecker bird, which is a sanguivore (blood drinker) (Photo: Flicker Sharing, Derek Keats)

12 of the Most Interesting

Let's face it, there are a lot of ways to eat and be eaten in the animal kingdom. Feeding ranges from the sponge-like mouth parts of flies to the flat molar-like chompers of clam-eating fish like black drum. If an animal or plant exists in the world, then something feeds in or on it. This is true of animals that drink blood, also called sanguivores (sang-wa-vors). Another word for this is hermatophagy (pronounced her- mat-oh-fay-gee). Any time you see the term "--phagy" at the end of a word it means "eating". Herma comes from the Greek word "haima" or "blood" and phagein or "to eat." For today's post I want to share with you the world of sanguivores or blood drinkers. There are more than you think, and even though you may already be squirming in your seat at the though, keep an open mind. Blood is little more than water with easily digestible proteins, lipids (fats), and nutrients. To humans blood is super taboo, and gross, we see blood as "disgusting" because we're taught that it's full of diseases and should only be seen in horror films. However, in nature blood is something not to be wasted or ignored. It's the "water of life" for some animals. Here are 12 of the most interesting.

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Red Velvet Ants or Cow Killer Ants

Velvet Ant (Photo: Mary Kiern Flicker Sharing)

It's Really a Wasp

Working outside, and in Education, I often get queries and questions about things people find in their yards or sidewalks. This week was no different, one of the researchers where I work messaged me asking about a big red fuzzy ant that has a black stripe on it. This fuzzy visitor is quite common in the Eastern US so it was an easy ID, but I thought it worth doing a post to introduce you to some quick facts about red velvet ants, also called cow killers, and their relatives. Most species of velvet ants are found in the southern and western parts of North America, and there are over 50 species in Florida alone,

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Wolf Spider Facts and Pictures

Wolf spider (Hogna Lenta) (Photo: Wiki Commons)

Is it Really the Big Bad Wolf?

Have you ever been out with friends, and you see a big hairy spider and someone yells, "wolf spider!"? Now the thing is, there are lots and lots of big brown spiders out there (and "big" is relative to how much you hate spiders too). Wolf spiders are the ones that have a bad reputation because they're big and brown and easy to see, and they have a fierce sounding name so people remember them. If they were called "floofy brown Betsies" or "hairy teddy bears" then most folks would probably just chalk them up to big brown things that happen to saunter through now and again.  But no...a biologist long ago thought that wolf spiders hunted like wolves, in packs, and they named the family "Lycosidae." This comes from the Greek "lycosa" meaning wolf. Any time you see an "a" after a Greek name it means the critter is a predator, it eats meat. In the case of spiders, bugs and other small creatures, this particular family name is misleading because wolf spiders the world around are really solitary and don't like hunting in packs. They do pounce on prey but not quite like a wolf does. So let's get down to some real wolf spider facts and pictures.

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Introducing the Butterfly Proboscis (Snoot, Sippy Straw & Sponge)

Butterfly tongue (Flicker Sharing: Thomas Quine)

How Butterflies Get Their Fluids

I think I have a form of nature attention deficit disorder because I get so easily distracted by anything in the natural world. In meetings I'm focusing on the sparrows outside my window and and analyzing their flock structure. At restaurants I'm looking at moths flying around lights and trying to identify them. I can't help it, it's what I do. Thus, while sitting on a dock watching the sunrise I noticed a butterfly probing a fairly fresh pile of scat that the morning's inhabitants had left. It sat there for a long time, probing with its long tongue and "dung sipping" (yes, there is a term called "dung sipping" that scientists use, makes for a great insult to other entomologists). Butterflies also can be found sipping carcasses and dead things too (so much for a butterfly's beauty eh?.."corpse sipper" anyone?). Here's a picture of what I observed:

Swallowtail butterfly drinking from dung (Photo: K. McDonald).

Most people that I meet think that when a butterfly visits a flower that it's using its tongue to sip nectar. This is what happens, but the butterfly's tongue is more like a combination sponge and sippy straw instead of just a straw. Let's start with the correct sciency terms for you to stash for future garden parties.....

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What Exactly are Raptorial Claws?

Rainbow mantis shrimp (Photo: Wiki Commons)

Raptorial Claws 101

I love random bits of nature trivia. I store them away like nuts in a chipmunk larder, to be taken out and paraded around when the right situation occurs. The term "raptorial claw" is one that most people will sort of know what it means, but not really, so for today's blog post a short introduction to my shiny chipmunk term of the day.

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What Does the Woolly Bear Caterpillar do in Winter?

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Woolly Bear Caterpillar (Photo: Graftendno1, Flicker Sharing).

How the Woolly Bear Caterpillar Survives the Cold

Have you ever wandered around a parking lot, sidewalk, or trail in the fall and seen a Wooly Bear caterpillar? They're the familiar fuzzy orange and black caterpillars that everyone dodges stepping on and that kids love to pick up and play with.

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Adult male Isabella Tiger Moth (Photo: Seabrooke Leckie, Flicker Sharing).

These fuzzy wee beasties are technically called the "Banded Woolly Bear" and they are the larval form of the Isabella Tiger Moth (Pyrrharctia isabella). The adult moth isn't very striking. It has golden-brown wings. They also have faint darker brown lines on their wings and the females have a pinkish-orange hind wing. The nice thing is that the caterpillar isn't a crop pest and mostly feeds on common deciduous forest trees such as elm, ash, low growing herbs, and other forest plants (they're not very picky and tend to sat away from gardens).

THE WOOLLY BEAR MYTH

Now most people have heard the myth that the woolly bear caterpillar can predict winter's length and intensity based on how much black is on them or how big the orange band is around their middle. This is really an old wives tale because as the caterpillar grows, during each molt (or shedding of its skin) the fuzzy black tips become less and less pronounced and the orange band grows. So, the caterpillar color barometer is really subjective based on which one you found and what molt phase it's in.  Not very reliable if you ask me.

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Adult woolly bear caterpillar (Photo: Wiki Commons)

So, seeing all those fuzzy cute woolly bear caterpillars got me to thinking and wondering, if they don't predict winter, what exactly do they do to over-winter? Where do they go? How do they survive? Seeing as they can't crawl very far they have to have some strategy to make it through freezing conditions. After all they are found all the way from the Arctic to North America and Mexico.

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The Bold Jumping Spider

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Bold jumping spider (Photo: Flicker sharing, Tibor Nagy)

Little Spider, Big Attitude

I'll admit it, I'm a big fan of little spiders, especially little wee hairy ones with big attitudes. That's why I wanted to feature the bold jumping spider Phidippus audax (say it with me, fid-DIP-us Ow-dax) for today's post. The name alone says it all, they're small spiders, about the size of those removable pencil erasers on mechanical pencils (6-13 mm), but they've got attitude enough for a mega-spider.

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Jellyfish Stings and How To Treat them

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Sea nettle (Photo: Baltimore Aquarium, Flicker Sharing).

Don't Pee on That Arm!

How many comedies have you watched where someone was stung by a jellyfish and the "hero" very selflessly offers to pee on the sting site? It really is just a comedy line, there is no truth in the myth and it can even make things worse! Yes, research as been done on this, and there's a great article in "Scientific American." If you'd like to read it, click here.  For this article I'm going to do two things:     1) Explain what happens when you get stung by a jellyfish and 2) Give you some treatment options.

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Lion's Mane Jellyfish: Winter Visitors to the Chesapeake Bay

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Lion's Mane jellyfish (Photo: Aplonid, Flicker Sharing).

Lion's Mane or Winter Jellyfish

As a kayaker and rower I tend to stay on the water as long as safely possible, right up until water and air temperatures become unsafe without a dry suit. Winter paddling and being on the water can be great fun, especially when you look for winter visitors that may be here for the season. One such visitor is the lion's mane jellyfish or winter jelly. Here in the Chesapeake Bay it's a common visitor to our waters in cold months. Many of my friends send me pictures asking exactly what they're seeing, and why there are jellyfish moving in the waters in winter, so I thought a post about these unique invertebrates might be in order.

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What Does a Tick Look Like? What Tick Is This?

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Adult female deer tick (Photo: Wiki Commons).

Identifying Ticks of the Eastern US

For those of you who are in the woods all the time you're probably pretty familiar with what a tick looks like. But there are plenty of people who aren't really familiar with what they look like, and let's face it, when you have one on you, you rarely take the time to check it out up close and personal, you just want it OFF! This post is dedicated to some basic tick anatomy (what they look like) and pictures of the ticks that are most commonly found in the Eastern US.  I've also created a nice quick table that should help you too.

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Sea Nettles and Oysters Need Each Other To Survive

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Sea nettles at the Monterrey Bay Aquarium (Photo: Wiki Commons).

How Sea Nettles and Oysters Are Related

Sea nettles are a type of jellyfish, and they are creatures that everyone loves to hate. They gum up nets, sting you when you least expect it, and make water sports difficult. Jellyfish are one of those classic examples or creatures that humans tend to dislike, but they are an important species for ecosystem balance. This is because, despite their occasional annoyance, without sea nettles there might not be any oysters to eat or harvest.

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Daddy Long-Legs Facts and Fiction

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Daddy long legs or harvestman (Photo: Wiki Commons)

An Introduction to Daddy Long Legs

As a kid I remember shrieking and being chased around the playground as little boys ran after the girls and tossed daddy long-legs us. Of course we all just knew they were man-eating spiders and we'd be bitten. Invariably though, the poor "spider" would lose a leg or two, fall quite short, and we'd race off to safety. Since then I've come to quite like daddy long legs and the members of their family, mostly because I think they get a pretty bad rap.

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Daddy long legs in the UK (Photo: Wiki Commons)

Daddy long legs are arthropods (which means "joint foot"), but they are not spiders. Even though superficially they look like spiders, and move like spiders, they aren't. Their family tree gets moved around a lot, because no one is quite sure where they belong, but most think they're more closely related to mites or scorpions (sans sting or venom). Sometimes they are called granddaddy long-legs, harvest spiders, or harvestmen. Daddy long-legs are found on every continent except Antarctica, and it's thought that there are nearly 6,500 species, 46 families, and 4 suborders world wide! That's a lot of species for a group that is commonly misidentified.

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Chiggers and Chigger Bites

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Scanning Electron Microscope image of a yellow mite (Photo: USDA.gov)

What Exactly Are Chiggers?

I have a lot of requests to cover topics about biting and stinging things, mostly because these are the critters that make people's experiences outdoors unpleasant. One such creature is the dreaded chigger. Now most of us have heard of them, and many of us have had their bites, but what are they really? What do chigger bites look like? Should you be worried? Let's start with chigger 101:

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Night-time Summer Activities for Kids

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Barred owl at night (Photo: Wiki Commons).

Keep Kids Busy and Learning on Summer Nights

This time of year is one of my favorites, it's warm enough to sit outside around a campfire, listen to the night sounds, play music, tell stories, or roast marshmallows. I've been asked to suggest some fun but also educational science activities for kids at dusk or night-time.

Night-time summer activities can be fun, and what you can depends on where you are, how safe the environment is to move around at night, and the age of the kids. Here are a few ideas you might consider:

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Sprickets (Spider Crickets)

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Camel cricket (Photo: Wiki Commons)

Why Do They Gather in My House?

It's been a while since I last did a post about sprickets, so I thought it was time for another, especially because I get so many questions about "spider crickets," also commonly called camel crickets.

These insects are the creepy wee beasties of some people's nightmares. They're actually crickets but with a hunched back.   They dwell in dark places and basements, and while it's bad enough that they look like spiders  these lookalikes take full advantage of the similarity to hop like a demented spring when startled, scaring the bejeebus out of basement goers.

Don't worry, sprickets are quite harmless, much like the grasshoppers you see in yards and fields. They don't have fangs, they aren't venomous, and they can't bite, but they are omnivores, eating just about anything in sight. This leads us to the question of the blog post:

Why do sprickets gather in my house?

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Mucus: Nature's Miracle Lubricant

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A snail gliding along on its mucus trail (Photo: Wiki commons)

Slipping and Sliding in the Natural World

It's that time of year when colds and flu are prevalent and everyone is hacking and sneezing, bemoaning their stuffed up and runny noses. I thought it would be the perfect time to discuss mucus. Yes, it's gross and one of those things people don't talk about, but everyone deals with it. It is also the lubricant that keeps the natural world from seizing and the animals sliding and gliding.

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What are the Differences in Spider Feet?

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The leg of a pink toed tarantula. (Photo: Wiki Commons).

Spider Feet For Different Purposes

For Valentine's Day my friends at the Smithsonian featured a cute little spider called the pink toed tarantula. This got me thinking about spider feet. They don't really have toes like you and I do, (though the idea of spider tube socks with toes is funny) but they do have special modifications that help them get about. The feet of spiders can be lumped into two general categories based on how the spiders make their living.   There are web building spiders and wandering spiders.

The demands of weaving a web and walking a continual tightrope, are very different from those of a spider that wanders, runs, and leaps on prey ( If you haven't read my post on spider legs you should check it out too).

The First thing to know about spider toes is that all spiders have hairy feet (which is why so many people find them creepy), but it's the arrangement and function of these hairs that varies.

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Fluid Support of the Hydrostatic Skeleton

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Sea anemone's have hydrostatic skeletons (a tube within a tube). (Photo: Wiki Commons).

Spineless Doesn't Mean No Support

Have you ever heard the words:  "You're spineless?"  While meant as an insult, it's actually a compliment in biological terms. You probably already know that some animals, like humans, have internal skeletons (endoskeletons), and some have external skeletons (exoskeletons), like insects. But the story doesn't end there, nature is much more complex and diverse. There is an entire class of organisms that has a type of skeleton, called a hydrostatic skeleton. It is just like the name implies, a static skeleton made of fluid (hydro).

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Giant Clam: A Living Greenhouse For Algae

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The interior mantle of a giant clam can be quite striking. (Photo: Wiki Commons).

How Giant Clams Act asGreenhouses for Algae

Normally I stick to North American species of animals, but I thought the story of giant clams was too good to pass up, especially because of the emphasis on the study of light in the Next Generation Science Standards.  Let's start with giant clam 101:

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Spider Legs: Hydraulics in Action

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Spiders are amazing works of engineering (Photo: Karen McDonald).

How Spider Legs Work

Let's face it, spiders are considered creepy by a large majority of people around the world. Yet when you ask them, most folks can't really name what it is about spiders that freaks them out so much. Usually explanations start with beady eyes, fangs, bites, or wrapping up their prey. Spider movement is also at the top of the list. They scuttle and scurry around at night (especially when you turn on the lights and they scamper off), jump, and generally run in a "creepy" way. But what makes their movement really foreign and creepy to us? The answer lies in two key elements of their anatomy, their skeleton and muscles.

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Butt Snorkels and Breathing Tubes Oh My!

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Mosquito larvae floating with their breathing tubes or butt snorkels at the surface of the water. (Photo: Wiki Commons).

Knowing Mosquito Biology Can Help with Control

It's that time of year again, when mosquitoes start to hatch and swarm and everyone starts swatting and pulling out the cans of insect repellent.  Now I know that butt snorkels doesn't sound like a true biological subject related to mosquitoes, but it really is.  And knowing about them can help you control mosquito populations in your area.

Mosquitoes are a type of fly in the Culicidae family, and their name literally means "little fly" in Spanish.  Many species are actually harmless, but in some, the females consume the blood of animals.  It's the blood-meal eaters that are often problematic, because they are disease carriers or vectors.  Their bites cause itchy bumps and are often quite irritating. That's not to say that they don't play an important biological role!  They are food for many species of other invertebrates, fish, bats, birds, and more.

Mosquitoes go through complete metamorphosis with a four stage life cycle of egg, larvae, nymph, and adult.  Female mosquitoes rely on fresh water to lay their eggs.  This can be as deep as a pond, as shallow as a dog bowl left filled and not refreshed, an old tire, or even the inner well of a flower or plant.  For those of us in the Eastern US, who are surrounded by fresh water and puddles galore, we constantly fight the standing water battle.  I knew of an elderly gentleman who paid kids $.10 per tire, lid, bucket, or container to dump the standing water in them.

Most female mosquitoes lay their eggs on the surface of the water.  The eggs can be in singles or in small rafts of up to 200 eggs.  Some mosquito females use a technique that is similar to dragonflies, where they tap their abdomen along the surface and drop the eggs into the water.  The eggs stage can last from 2 days to many months, depending on the species, season, and weather.

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Mosquito life cycle (Photo: Wiki Commons).

After about 48 hours, a young mosquito hatches into a larvae.  The larvae (and pupa) are the ones with butt snorkels, or breathing tubes called siphons.  The tube is an extension of their spiracles (or breathing holes along their sides -- those are used more in later life when they become terrestrial).  The larval mosquito's butt snorkel has a fine ring of hairs and a waterproof material that help to break the surface tension of the water molecules.  This allows the snorkel to take in air.  Butt snorkels aren't all that uncommon in the aquatic insect world, some species of water scorpions and other flies have them too.  Some insects like aquatic beetles attach a bubble of air to their butts when they dive, and then breathe through that.  Insect butts are fascinating.

www.mantis.cz/mikrofotografie

Here's a close up look at the head and abdomen of a mosquito larvae. Check out the nifty butt snorkel on this guy!

The larvae are not blood suckers yet, they are microbial feeders eating plankton, algae, and other micro materials with their brush-like mouth parts.  To get away from predators they often flex their body in a jerky movement.  This movement can help you identify them when you're looking in ponds or puddles.

After molting their exoskeleton about four times, the larvae then develop into a pupa.  The pupa is described as comma shaped because they have a large head, fused with their thorax, to make a cephalothorax.  Their abdomen is still long and skinny, and they must still use butt snorkles to come to the surface to breathe.  Much like their larval stage, these pupa can use the power of their abdomen to flip around and move, so they're called tumblers.  At this stage many do not have mouth parts, and they are simply hanging around with their butt snorkels in the air waiting to change into an adult.  Pupation can take anywhere from 2 days to months.  Here in the US many of the common species take only two weeks to complete their cycle.

After pupating, the mosquito splits its skin, and then emerges as an adult.  Much like a butterfly emerging from a cocoon, the adult must harden its body and extend its wings to dry and harden, before it can fly.

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An adult mosquito feeding on human skin. (Photo: Wiki Commons)

If you want to control larval mosquitoes and get them before they become adults, then it's good to know about their butt snorkels and their feeding habits.  First, if you can, remove all sources of standing water.  This includes cleaning gutters, plant pots, refreshing bird baths, turning over tires, emptying cans, etc.  Next, for water that you need standing and can't eliminate, try adding a water bubbler.  The bubbling causes too much wave action for the mosquitoes to be able to use their butt snorkels and they drown, which is why you don't have many mosquito larvae in fresh running streams or waterways that move a lot.

You can also use a VERY thin layer of vegetable oil on the surface of a standing pond.  This layer does not allow the mosquitoes' butt snorkels to penetrate the surface of the water.  Be aware, this may affect other insects that come to the surface to breathe, or aquatic plants, so use with caution.  If you do use this method, use a spray bottle with water and a few drops of oil.  Gently spray the surface of the standing water until you see a thin "slick."  This should evaporate in a few days, so you'll have to re-apply.

If it is feasible, one of the best methods of larvae control is using mosquito fish or tadpoles. Remember to use native species if you plan on introducing them into your body of water.

Last, but not least, you can also use bacteria.  There are two species, Bacillus thuringiensis israelensis and Bacillus sphaericius, which can be added to water.  These types of bacteria are eaten by the larvae and they then die from the toxins that the bacteria produce.  The bacteria are suggested by the EPA and are thought to be safe and effective.  You can read more on their website.  My main concern with this type of control would be the effects to other native insects, so use with caution and weigh your options!

Here's a great video that you watch about their life cycle

Mosquito Life Cycle

I know that mosquitoes are a pain, but they are also biologically important.  The best control you can do is prevention.  If you can't prevent them, then knowing about their biology and their butt snorkel physiology can help in treating for them.  Besides, now you have a cool nature fact to drag out at those summer picnics!

Stay tuned for more insect abdomen posts.  Mosquitoes aren't the only ones with unique posterior appendages and uses.  Female crickets have funky ovipositors (egg laying tube) and turtles can absorb oxygen and breathe through their butts!  Biology is awesome.

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Check out the ovipositor (egg laying tube) on the abdomen of this cricket. (Photo: Wiki commons).

 

 

Stink Bugs: Will They Bite and How Can I Get Rid of Them?

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The Brown Marmorated Stink Bug (Photo: Wiki Commons).

Brown Marmorated Stink Bugs

Stink bugs are one of those creatures everyone sees, but no one really understands or likes, and for good reason.  The Brown Marmorated Stink Bug (Halyomorpha halyes), also known by BMSB, first showed up in the US around 2001 in Pennsylvania.  It's thought to have been brought in with either fruits or fruit trees of some sort.  As a native to Eastern Asia it is truly an invasive.  Even in its home countries, it's a pest, including in Japan, Korea, and China.  In the last decade or so they have invaded over thirty-four states in the Mid-Atlantic region of the US, including Washington DC.  They were first seen in Oregon and out west around 2004 and since then they've spread in California and other states.

I'm going to call these guys stink bugs for now because Brown Marmorated Stink Bug sounds good, but it's long to type and BMSB just looks funny.  The stink bugs we're talking about are mostly brown or marbled brown and tan on top and whitish grey on bottom.  They are usually about 1" long as adults, smaller as nymphs.  They belong to the Hemiptera, or "true bug" family, and more specifically, to the suborder called Heteroptera.  That's not to say that there are false bugs, but true bugs are "typical insects" with the usual set up of body parts and legs. Hemiptera, also, all have piercing mouth parts (bug sippy straws).  Stink bugs and Heteropterns also have a special set of wings (Heteropera means "different wings" in Greek). Their type of wings are called hemelytra.  The wing part nearest their head is leathery while the part near their rear is membranous like the wings of a dragonfly.  If you look carefully at the stink bug's back you can see a large X.  It's this X that lets you know it's in the hemiptera family.  There are two triangles formed by the X, one near the head, and one near the rear. The one near the rear is the set of membranous wings folded up.  X marks the spot when you're looking for all true bugs.

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X marks the spot when looking for a true bug or Hemipteran. You can see the unique wing configuration of this stink bug, with the leathery wings on the top of the X and the membranous wings at the bottom. (Photo: USGS, Wiki Commons)

To be sure you're looking at a brown marmorated stink bug, and not a native US species, be sure to look for the white bands that are on their antennae.  There should be one near the antennae joint, and sometimes a smaller one or two closer to the head.

When talking with friends and "non-bug-folks", some of the first questions they ask are:

1. Do stink bugs bite?  Nope, you're safe.  If you look closely at these little home (and crop) invaders, you'll see that they have a straw like projection that tucks up under their head. This is a sucking proboscis.  It can pierce the flesh of fruit, such as apples, pears, and peaches, so it's not out of the question that it could give you a short poke or stab, but this is rare.  They don't sting either.

There are other Hemipterans that can give a much worse poke than the stink bug.  Check out this picture of an Assassin bug sucking the life juices from a beetle.

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An assassin bug sucking the juices from a tortoise beetle. (Photo: Wiki Commons).

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The Gastric Mills of Crayfish and Other Crustaceans

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Crayfish use gastric mills to help break down their food. (Photo: Wiki Commons).

"Chew All Your Food Dear....With Your Stomach!"

It's not often that you can wax poetic about the chewing, grinding, and digesting of invertebrates, but here goes.  Many crustaceans are highly specialized for their aquatic lifestyle. Inside their digestive system they have a unique stomach that is called the GASTRIC MILL. The gastric mill is found in crabs, lobsters, crayfish, barnacles, krill, and many others. These invertebrates don't have teeth in their mouth to grind their food, so they process it a bit differently.  Their claws rip and tear apart their food (mostly plants and animals), their mandibles (or mouth parts) shred the food down a bit more, and then it is passed on to the digestive tract. The gastric mill functions a bit like a gizzard in a bird, but unlike a gizzard which has rocks and sand for grinding the food, the gastric mill has strong muscles which are folded into ridges that increases surface area for absorption and helps in mechanical breakdown of the food.

Depending on the species of crustacean some have ossicles or calcified plate-like structures in the stomach (much like the flat surfaces of molars) while others have chitenous gastric teeth.  Chiten is the same material that the arthropods shells are made out of, and is very strong.  In some cases, after going through the gut, food particles may still be too large or hard to break down, then the particles may be ejected back out of the mouth and reprocessed.  In many crustaceans, there is a set of glands within the stomach to help with digestive absorption and secretion.

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The Infinite Spider Blog: Origin of a Name

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A common garden spider (Photo: Karen McDonald)

How the Infinite Spider Blog Got Its Name

I’ve been asked by quite a few readers to explain why I chose the name “Infinite Spider” for my blog, and what the symbol means. So in this post, I have partnered with Anne Littlewolf  to give you a bit of information about this symbol and the name of this blog.

As the Bard so rightly said, “That which we call a rose, by any other name, would smell as sweet”.  But roses and spiders seem to be at opposite ends of the spectrum of human emotion.  Roses make us fall in love, spiders send us into a screaming panic (OK, sometimes the two resemble each other) searching for shoes, rolled up paper, fly swatters and other such ammunition.  It’s guaranteed to get you lots of adoration if you rescue your partner from the dreaded Arachnidus Superbadus.  So why name this blog after a spider?  And why do we have such loathing for spiders and their kinfolk?  Yes, they are small and hairy, and they have far too many eyes and fangs… but really?  Most are less than ¼” in size?

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Discovering Diatomaceous Earth

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Diatoms as seen through a microscope. Note their stained glass window shapes and silica bodies (Photo: Wiki Commons).

To Use or Not to Use, That is The Question

As Spring infestations of pests, fleas, and insects begin, many homeowners are faced with how to control these critters, either in the home, garden, or even on pets. If you're like me, you'd rather stay away from chemicals all together. There are many different natural solutions out there for different organisms, but it's difficult to tell what works and what doesn't. In coming posts I'll explore some of these solutions, but I want to start with Diatomaceous earth.

Diatoms are a type of microscopic aquatic plankton or algae (2-200 micrometers in size). They are small photosynthetic plants.  We owe almost every other breath that we take to these numerous wee producers that are respiring in our lakes, rivers, and oceans. Their shells are made up of silica and calcium carbonate. In essence, they look like tiny stained glass windows.

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Pictures of diatoms under the microscope (Photo: Wiki Commons).

Their bodies are made like a gift box, with a top that slides over a bottom. When they reproduce, their two halves separate and then regenerate a new half. In the oceans, they are estimated to provide nearly 1/2 of all the primary food production for aquatic life! They've been around for a long time, all the way back to the Jurassic. Their glassy bodies have been floating around providing oxygen and food for millions of years. As these small organisms die, their glass bodies either sink to the bottom of the ocean or become sediment deposited on shorelines. When you look at sand under a microscope, you'll often see tiny grains of rock, but you'll also see the remains of diatoms. The main ingredient in making glass is silica, which is added in the form of sand. Guess who provided all those bits of silica? Diatoms!

Diatomaceous earth, or diatomite, is made up of the sedimentary deposit of fossilized diatoms deposited over millions of years.  They are usually whitish and abrasive feeling because of the nature of the silica, though the food grade kind may feel as soft as talc. It is very light because it has a high porosity and it is not combined with all the other heavy elements of rock and sand that are found in sedimentary sandstone.

Diatomaceous earth has been used in a variety of industrial settings, including for filtration, reinforcement of plastic, abrasion for tooth pastes, fillers for rubber and cat litter, and even stabilizing dynamite. One of its more common uses is as an insecticide.

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Diatomite from a mine in CA (Photo: AlishaV. Flicker)

As a pesticide, diatomaceous earth must be unheated or calcified (which is often done to increase its filtration value). Calcification burns or melts the silica, reducing its efficacy. If you were to look at diatomite under a microscope, you would see startling edges. These glassy edges are sharp as razors to invertebrates, but won't hurt humans or large animals. This is why it has been touted as a natural pest control. Before you get too excited though, let's really examine what it does to control all of these "pests."

Diatomaceous earth acts as a very strong cutting abrasive on the exoskeleton of invertebrates, including bed bugs, fleas, ticks, worms, slugs, and all six and eight legged insects. It is essentially the "death of a thousand cuts." Those cuts open up the organism to dehydration and infection within 24-48 hours, causing death. The other property of diatomaceous earth is that it is absorptive. It acts to dry out and desiccate the microorganisms that are cut by its sharp edges. So, how is this bad you ask? Diatomaceous earth is a generalist. When you apply it to your garden, you are in turn, not only killing the harmful slugs, grubs, roaches, silverfish, aphids, and thrips, but you're also killing all the beneficial insect life as well. This includes earthworms, pill bugs, ants, beetles, ladybugs, beneficial caterpillars, and more. This generalist approach is detrimental to the ecosystem, though perhaps less so than most chemicals. The other down-side to diatomaceous earth is that it loses its potency once it rains and the diatoms clump together. It has to be applied during dry days without rain.

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Beneficial jumping spiders may be negatively impacted by diatomaceous earth (Photo: Karen McDonald).

As with all pesticides, you have to consider the ramifications of using it in your garden or around your home. Yes, diatomaceous earth is mostly harmless to humans and pets (with a few exceptions of inhaling etc., and it is a controlled substance through the USDA), and yes, it can be quite effective in killing grubs and other garden pests. However, it's a generalist and like other chemicals, it kills everything indiscriminately. On a microscale, I can only imagine the "gory movie scenes" of what really goes on in the undergrowth and below ground once it is applied. I can picture the razor like edges cutting the microinvertebrates and their slow desiccating deaths. I have my own opinions, but everything has a cost and must be weighed. What do you think? Would you use it? Have you used it?

 

Ant Teaching Resources for Your Classroom

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An ant keeping his aphid "cows" safe. (Photo: K. McDonald)

Free and Low Cost Resources

As many of you know, I lead a double blogging life with my Citizen Science in the Classroom series on the umbrella citizen science site called SciStarter. If you haven't checked out their plethora of citizen science activities that you can get involved with, then head over to their site. In my series, I focus on specific citizen science projects and then help teachers figure out how to conduct those projects to meet grade specific, Next Generation and Common Core teaching standards. While writing my last post about a project called School of Ants, I was amazed at how little there is out there for teaching about ants. I had to do a great deal of digging to find teaching resources. But when I did, I found some great ones that I thought I'd share here. You can also check out my SciStarter blog post with Next Gen. and Common Core connections.

My favorite resource so far is Dr. Elanor's Book of Common Ants. This is a great free resource with wonderful illustrations, large ant pictures and close ups, and clear text. It's written for adults, but it's also kid friendly (4th-12th Grade). This book, along with a magnifying glass, is all you need to get yourself started with basic ant ID (or toss your kid outside with it and get them busy discovering on their own). I loved learning facts about pavement ants, winter ants, and the common little black ants called the "Odorous House Ant." Odorous house ants are the tiny little black sugar ants that come into the house. She suggests the "Squish-n-Sniff" for these guys because when you squish them, they smell good! This is how they got their names. How fun is that? If you are a naturalist at heart and want to learn more about ants, then this is the go-to resource.

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Dr. Elanor's book is an amazing resource. (Photo: Your Wildlife)

I found some other great teaching resources that might be helpful as well, such as :  ant lesson plans, MP3 interviews with ant researchers, free life cycle and anatomy worksheets, instructions for building an ant colony box, and more that come out of Arizona State University. If you haven't heard about their "Ask A Biologist" teaching resources, it's time to pop over to their pages (click here for their activity page). They have much more than just ant materials. You can find lesson plans, interviews, and worksheets, about plankton, space physiology, the nervous system, and more. It's worth visiting.

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Arizona State University has a great website on ants (Photo: ASU)

I also stumbled across a great video about ants on YouTube. It's called "ANTS-Natures Secret Power." It is a bit long to show in class (about an hour), but you could use segments or assign it as homework to the students.

I'd also like to suggest some of the following books:

DK Readers: Ant Antics. Lock. [2nd-4th] (used $.01)

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Are You an Ant? Allen and Humphries [K-5th] (used $1)

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The Fascinating World of Ants. Julivert et. Al. [2nd-5th] (used $.01)

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Journey to the Ants: A Story of Scientific Exploration. Holldobloer and Wilson. [Adult reading and reference] (used $.50)

EO Wils

There are many more books out there that are great, these are just a few. If you need magnifying glasses, ant farm kits, or other supplies, you can find resources on my "Nature Gifts and Teaching Supplies" page. The wonderful thing about ants is that they are everywhere and require very few materials to study and observe. Happy "anting" (this is actually a term used by birders when birds rub ants on their feathers for some unknown reason, but I think it applies here).

 

Tardigrades: Learning About Water Bears and Resources for Teaching

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Water bear in active state (Photo: Flicker, SaguartoNPS).

Tardigrades in Your Own Backyard!

One of my favorite invertebrates is the water bear or tardigrade. It is arguably the most extreme animal on Earth in the unassuming cute and cuddly form of a moss piglet with bear like claws. In this post I'm going to share with you some of the amazing natural history of tardigrades and some teaching resources that you can use for an indoor or outdoor classroom. If you're like me (and love exploring things like this) then you probably will also want to check these cool little guys out at home too, though you'll need a compound microscope to see them.

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Tardigrade in active state (Photo: Wiki commons)

Tardigrades belong to the phylum Tardigrada. They're aquatic invertebrates commonly found in the base of mosses and lichens; though they can also be found around the world, from the heights if the Himalayas to the depths of hot springs. They are known as extremophiles, meaning that they can live in places on Earth that most creatures couldn't handle. They can endure temperatures of absolute zero, pressure higher than that of the deepest oceans, radiation that would kill all other animals, and they can go without food or water for more than 10 years! Now you'd think a creature that can handle these extremes should be the large and flashy  but they're actually not much bigger to 1/2 a millimeter, about the size of the period made by a .5 mm pen.

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Leopard Slug Mating is Well....Strangely Beautiful

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Leopard slugs can be quite large, this is a beautiful specimen (Photo: Flicker Sharing, NorthDevonFarmer)

or "Ewwww, I Can't Look Away"

So once in a while I have to veer off track and bring you something completely different (much like my previous post on 50 foot cockroaches). Today I want to share with you something so gross and disgusting that it's almost beautiful (sort of like hairless cats and Shar pei dogs), leopard slug mating. Now for those of you that are gardeners you probably find leopard slugs (Limax maxiumus) a great nuisance that eats your vegetables and leaves slimy trails everywhere, but they are really much more complex (and a good cup of stale beer put out at night will take care of the problem).

Slugs 101

All slugs and snails are in the phylum Mollusca, along with squid, clams, and octopi. Slugs are gastropods, literally meaning "foot mouth". Leopard slugs have a noticeable mantle on their backs and in almost all species it's black spotted. They also have two optic tentacles with eye spots on the tips and two below them for feeding and tasting. Their anal opening is under the mantle (on the right side of the head) and they are hermaphrodites with both male and female genitalia.

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Anatomy of a slug (Photo: Wiki Commons)

Also on their mantle is a large hole or respiratory opening (called the pneumostome) that leads to lung-like tissue for respiration. Their respiratory opening opens and closes at regular intervals to prevent dehydration. Slugs glide along on a large muscular foot. The leading edge of the foot is called the "skirt."  Mucus is produced in glands on the "sole" of the foot. This mucus has specific pheromones that attract other slugs and also acts as a signal, trail marker, and travel lubricant. Underneath the smallest pair of tentacles is the rasping and chewing mouth part that are used to chew plants and vegetation.

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Identification Tips for Brown Spiders of the Eastern US

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A wolf spider carrying its egg sac. (Photo: Wiki commons)

Knowing What is and is Not A Brown Recluse or Wolf Spider

I'm often amazed at the number of times I've been outdoors with someone and when we see a brown spider immediately someone says, "Look, there's a wolf spider." I have to admit, I hate identifying "little brown jobs" or LBJs (a term we use commonly for brown sparrows when birding) because it's hard to find the fine distinctions between species, especially when the creatures are moving  or you're just skeezed out by the hairy eight legged creature crawling across your floor. However, it is important to understand that not all brown spiders are wolf spiders.

There are many different types of brown spiders and this blog post will help you begin to tell the difference between them. I'm going to write mostly about the spiders common to Eastern and mid-western North America, because this is my home range, but there is some overlap with western species.

A great starting place to learn spider ID and to become familiar with their body parts, names, and  the eye placement of spiders is on the website "Spider Identification Guide." I am particularly fond of their great graphic on the 25 different eye patterns you can find on spiders (I wonder if they make this in poster form?). Begin with the basics of spider anatomy on their website if you need a refresher. They also have a great guide for finding spiders by region and color. Check out their page on "Brown Spiders" for a quick browse of the diversity out there.

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An Introduction to the Teaching and The Citizen Science Website Journey North

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Journey North, a Citizen Science Website for Everyone

Journey North is a Citizen Science Website That Tracks Phenology (life cycle changes in plants and animals) and Seasonal Changes

Spring weather has briefly visited us this week, though the cold is coming back soon. But invariably we're seeing the first signs of Spring everywhere. This weekend the first osprey was spotted locally, geese are migrating, red-winged blackbirds are singing out their territories, and I heard a lone spring peeper. With thoughts of spring it's a good time to make you aware of a wonderful resource for citizen science. The website Journey North is designed as a tool for individuals and classrooms, as well as informal educators, to use for tracking seasonal changes and migrations. The term for tracking the seasonal life cycle changes of plants and animals is called phenology. This website provides the tools to track the phenology of robins, humming birds, whales, barn swallows, worms, first leaf-out, eagles, flowers blooming, caribou, whooping cranes, and so much more. They also specialize in providing tracking maps and information for recording seasonal changes in sunlight and weather.

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Examples of projects found on the Journey North website and "teaching" pages.

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