If you're like me, you get up in the middle of the night to either go to the kitchen to grab a bite, or hit the bathroom. Now, usually I avoid turning on the light, but sometimes you just have to. It's then that you see the quick silvery flashes of insects moving like those dragons you see at the Chinese New Year, back and forth scuttling quickly for their lives. Those are silverfish (Lepisma saccharina), and in this post we'll explore exactly what silverfish are, why people don't really like them, and a few ideas for helping secure your home from them.
A Story of Prehensile Jaws, Butt Propulsion, and Biting Mouth Bits
Dragonflies are one of those creatures that people love and hate. They show up on Memaw's knitted sweater, baby onesies, wine glasses, and summer napkins, but when it comes to actually seeing them in the wild many people cringe. They're fast moving, multi-winged, and bug-eyed creatures that look like aliens. Two of the most common questions I get asked is "Do dragonflies bite?" and "What do dragonflies eat?" In this blog we'll cover both questions, and the extraordinary world of dragonfly feeding, from prehensile jaws to mandibles.
Starting in spring bees and wasps begin to appear and I can always tell that people are concerned because my posts on "What Bit Me?" gets a lot more traffic. I completely understand fear and phobia of bees, ranging from concerns of severe allergies to those that have watched horror movies. As a former bee keeper though, I truly love and respect bees. One of my most favorite types of bees are the carpenter bees (here in Maryland we have Xylocopa virginica). Yes, they can be destructive; yes, they are big; and yes they can be scary, but when you really study them they're quite interesting. So, on to the question, "Do carpenter bees sting?" And more importantly what should I do around them?
Cecropia Moth (Photo: Flicker Sharing, Charlie Kellogg)
Identifying Big Moths of the Eastern US
Around this time of year I find a lot of moth cocoons and newly emerging moths at night. I thought it would be a good time to review some of the big moths that you may find in the Eastern US, and what they look like.
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,
This time of year there is a fun abundance of moths and insects flying around at night, and often hanging on buildings during the day. One such popular moth in our region is the luna moth (Actias luna). Luna moths are the charismatic megafauna of the moth world. They're big and flashy and easy to spot, as well as being quite harmless. In honor of these beauties, and the summer nights, here are ten interesting facts about luna moths.
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.
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.
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.
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.
Have you ever been digging in the garden or your flower bed and come across a HUGE grub or large black beetle? If you've ever spent any time digging around outside or under logs in the Eastern US (or Midwest) then you've probably encountered our guest beetle for today, the Bess beetle or Bess bug . Their Latin name is Odontotaenius disjunctus (O-don-tote-a-knee-us dis-junk-tus). Odon means "tooth" and taeni means "band" or "ribbon". This refers to the bands of teeth on their bodies (abdomen and wings) that they use to make sound. Dis refers to "separate", "double" or "two", and junc refers to a "rush" or "reed". This may reference that they sound like rushes or reeds rubbed together.
Bess beetle (Photo: Wiki Commons)
Bess beetles are one of the largest beetles you can find (1.2-1.6" long) and can be quite startling. Their backs look like shiny patent-leather dress shoes with legs (there's an image for you). Their bellies have golden hairs and their head has a single horn. Bess beetles are in the scarab super-family (Scarabaeoidea), and there are over 500 species around the world. The Bess beetles of North America (Odontotaenius disjunctus) are one of the few scarabs in the US. Look carefully and you can see the characteristic scarab looking club-like antennae on their head.
Bess beetle (Photo: Flicker Sharing, Cotinis)
The common Bess beetle name probably comes from the the early English term buss meaning "kiss" or the French term baiser or evenune bise, which also means "to kiss." Both sound very close to "Bess." This name may attributed to the noise that the beetles make when they're startled or feel threatened. It's akin to a "kissy-sound," like what you'd make when making fun of your older brother kissing his girlfriend or the practice smooches you did as a kid in the mirror. The sound is made much like how a cricket makes sound, by rubbing body segments together, a process called stridulation (st-rid-you-lay-shun). Listen to this...
As a child you learned about bees and how they fly from flower to flower pollinating the plants, and that they carry the pollen on the hairs of their legs while some even carry it on hairs their bottoms (called scopa). However, there's another way that bees can pollinate that most people don't know about and its immanently useful for gardeners to be familiar with. The process is called sonication or buzz pollination.
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.
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.
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:
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:
Bumblebees like this can sting multiple times, and don't leave in a stinger (Photo: Karen McDonald)
What To Do If You're Stung
At the best of times it's nearly impossible to avoid bees and wasps. Regardless of how most people view them, I'm a huge fan of bees and wasps. This is because they help pollinate plants to create food and they eat other insects. The upshot is that nature has armed them a defense that humans find painful, stings.
I'll say this up front, I'm not a doctor, but I have been an outdoor educator for over 15 years, and I've been stung, or dealt with stings, in places you don't want to imagine (including the tongue). From these experiences I wanted to share with you ways to find bee sting relief and what to do for a bee sting if you are stung.
Ladybugs are familiar sights in the Spring. (Photo: Wiki Commons).
Biting Ladybugs: Should I Run and Hide?
Ladybugs are one of those insects that even non-insect lovers tend to like. They're bright and colorful, tickle when they walk, and are easy to handle and play with. Kids don't feel threatened by them and adults will often go out of their way to move them or take them outside. There are countless children's story books about the wee creatures. However, they are still insects. In this post I want to share with you the awesome life cycle of lady bugs (you will never guess what they look like as babies!), their mouth parts/anatomy, and a few ideas for lessons or teaching materials.
Monarchs in Pacific Grove California (Photo: Wiki Commons).
Do They Really Travel That Far?
Right now, Autumn, is the time of Monarch Butterfly migration. You can see monarchs languidly gliding on the cool fall air against a backdrop of colorful leaves and scattered pumpkins. When I lived along the coasts of Delaware I loved to see the monarchs cross the dunes on fall winds. This brings me to one of the most common misconceptions about monarch migration, which is that it's one butterfly that makes the entire trip North and South for migration.
A bee with its mandibles and sucking mouth parts. (Photo: Karen McDonald)
Answering Questions About Spider & Insect Bites and Stings
When I take groups into the woods, along the shores, or into the field, invariably we have to deal with bug bites. One of the most common questions I get is, "What does a spider bite look like?" or "How can I tell what bit me?" It's a tough question to answer, but I'll try to provide you with some basics of what to look for.
There are more insects and invertebrates on Earth than any other living creatures, thus it becomes difficult to specifically classify how they all behave and how they interact with humans, in part because it varies by where you are, the temperament of the crawlie wee beast, the invertebrate's physical make-up, your physical chemistry, etc. However, there are a few commonalities you can look for.
NOTE: I am not a medically trained doctor, so please take the materials below as general advice and guidelines, and seek professional treatment if you have been bitten or stung, and you need assistance.
First, Not All Things That Bite And Sting Are Insects
Remember, all insects have three body parts and six legs. This means that not all invertebrates that bite are insects. This is true of spiders, which have two body parts and eight legs, as well as ticks, chiggers, scorpions, and leeches.
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.
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.
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.
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 thuringiensisisraelensis 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
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.
Check out the ovipositor (egg laying tube) on the abdomen of this cricket. (Photo: Wiki commons).
How to Identify and "Call" Lightning Bugs or Fireflies
Photinus sp. (Photo: James Jordan, Flicker Sharing).
An "Enlightening" Conversation
As summer rolls around it's time again for the emergence of fireflies or lightning bugs. These benign insect ambassadors have been many children's introduction to the world of beetles and friendly insects. For today's post I will introduce you to the three most common groups of fireflies in the Eastern US and how you can use LED flash patterns to call the most common species to you. It makes a great lesson plan for evening programs or just something fun to do with the kids on a summer night.
Fireflies, or lightening bugs, are beetles (order Coleoptera). Unlike their cousins, that have hard-bodied elytra (ee-light-tra) or wing coverings. Their bodies and wings are relatively soft and they have leathery wing coverings. The are usually about 2 cm long, and blackish with reddish or yellow spots on their head covering. The head covering is also called the pronotum (pro-know-tum). Around the world, there are over 2,000 species of fireflies, and most live in tropical, moist and damp areas, in part because of their soft bodies. Lightning bugs are called this because their abdomens light up using a chemical process called bioluminescence.
In the Eastern US there are three common families of fireflies that we see, Photinus (Foe-tine-us), Pyractomena (Pie-rack-toe-mean-A), and Photuris (Foe-tur-is). You can distinguish them apart by looking at their head covering and their wings.
Stink Bugs: Will They Bite and How Can I Get Rid of Them?
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 calledhemelytra. 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.
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.
An assassin bug sucking the juices from a tortoise beetle. (Photo: Wiki Commons).
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?
A mantis egg case or ootheca (Photo: Flicker Sharing, Lori Erickson)
A Quick Introduction
Now that Spring weather is finally upon us, it's time to talk about hatching young. In today's post I want to introduce you to preying mantis egg cases. Early spring is a great time to spot them because they usually hang from twigs or they are laid on bare wood and natural surfaces. Without leaves to obstruct your view (or in early leaf out), they're fairly easy to spot.
Praying mantises are invertebrates that have incomplete metamorphosis. This means that their young look like little adults and they don't make a cocoon like butterflies. Their life stages are egg, nymph, and adult. I'll do another post on mantid natural history later, but for today, I'm going to focus on their egg cases.
There are over twenty types of mantis native to the US and they are wide-spread. The Carolina mantis is the most common and there are two introduced mantis species from China and Europe. Most of these species are insectivorous (eating insects and sometimes even small mammals or hummingbirds) and they participate in the cannibalism of mates (females eat the males during reproduction). I will say from experience, that young mantises, unless separated, will also eat each other. In the Autumn when the days are still warm, mantises will mate. After mating, females lay between 50-400 eggs in a foamy egg case called an ootheca. The foam is secreted from a gland in her abdomen. This foam looks white when laid, but it turns brown as it hardens.
A mantis egg case laid on twigs (Photo: Flicker sharing, Mike Maehr)
Here is a cross section of what an egg case looks like when laid open. Notice each egg has its own chamber and exit to the outside of the egg case.
There are a variety of shapes and sizes of mantis egg cases, and as you can imagine, they vary by species though many are very similar. If you haven't checked out Bugguide.net, they are a great resource for identifying insects, eggs, nymphs, and larvae of all sorts of insects, including mantises. Check out the images of different types of mantis egg cases on their web page.
An example of a common type of mantis egg case. (Photo: Flicker sharing John Tann)
Here are a few images of mantises actually laying their eggs:
This is a New Zealand mantis (Orthodera novaezealandia) laying her eggs. (Photo: Wiki commons)This mantis is laying her eggs in the corner of a mud wall. The white color will harden to brownish color. (Photo: Wiki Commons).
The emergence of the young is like watching grains of rice, with little black beady eyes, wiggle out of the foam cases and then their legs deploy. When they finally stand up, they look like little miniature mantises. At first they are light colored, but as they mature and molt their deeper color comes in.
There are several types of parasitic wasps (Podagrion sp.) that will prey on the egg cases by depositing their eggs into the mass to feed on the mantises eggs and larvae. The wasps are tiny and usually have very long ovipositors (long tubes for sticking into the ootheca). Click on this link to bug-net for some images and also the OZ website for some up close images. This is something to be aware of if you're going to rear mantises for your class or inside the home.
It's quite fun watching mantis egg cases hatch in the Spring, and it's a great experience for students to watch the emergence. If you plan on bringing an egg-case inside, be sure to provide it with a mesh cage, with plenty of air circulation. You can tie it to a twig or branch. The little mantises should hatch in early to mid spring. It's best to take them outside where they came from once they hatch. Rearing isn't too difficult, but it's time-consuming and requires feeding flightless fruit flies or other insects and checking on them every day. If you don't feed them enough flies, crickets, or aphids, they will eventually cannibalize each other. You'll be left with one large mantis with a smile on its face!
Here are a few places you can find rearing information:
You can also buy kits online from a variety of sources from $30-$50.
Mantises are a fun organism to watch and observe. When you're out hiking, look for these brownish egg cases and know that our insect friends will soon be hatching.
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.
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.
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.
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?
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.
Dr. Elanor's book is an amazing resource. (Photo: Your Wildlife)
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).
An Introduction to the Teaching and The Citizen Science Website Journey North
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.
Examples of projects found on the Journey North website and "teaching" pages.
Winter Searching for Paper Wasp and Yellow Jacket Nests
An aerial paper nest made by yellow jackets. (Photo: Karen McDonald)
Exploring Paper Wasp Nests (and yellow jackets too!)
Winter is the perfect time to look for things that are typically hard to see when trees are in leaf. This includes birds, mistletoe, and wasp nests. It's not unusual to see yellow jacket nests that are grey, round, and large in the upper branches of trees, but how much do we really know about paper wasps and yellow jackets? Are they still in there over the winter? Is it safe to approach? Let's look at these fascinating creatures in more detail.
Sorry B-Flick Movie Lovers, 50 Foot Cockroaches Can't Really Exist!
I absolutely adore good B-flick movies, especially those with giant lizards, killer tarantulas, man-eating mole rats, and destructive turtles. However, the biologist in me always has a running commentary in the back of my head when I watch those films, I can't help it. So, just because it's useless fun knowledge, here's why it is impossible for fifty foot cockroaches to exist:
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