Saturday, 24 August 2013

What Are Those Funny Looking Tumours Growing on Goldenrod Plants?

Newly formed gall on Goldenrod Plant
Have you ever noticed those strange tumour-looking bulges on some wildflowers?  especially Goldenrod plants?  I didn't know what these were, and your students probably don't either. 

Living inside these round spheres are tiny insects!  Called "galls" or "cecidia"   these bulges are actually hibernation dens!

A parasitic fly called the "Goldenrod Gall Fly" [Eurosta solidaginis], lays its eggs on the stem of a Goldenrod plant.  The female fly injects her egg-laying tube called an "ovipositor" into the Goldenrod stem.  In about 10 days, the larvae hatch and begin to eat the inside of the plant's stem.  The swelling and creation of the round-shaped gall is the plant's response to the insect living inside.  The larva is laid in spring and will live inside the plant for the entire summer.  Sometimes galls become very big - about the size of a Ping-Pong ball!

Dried gall showing exit hole.
As winter approaches, the larvae produce a chemical that prevents them from dying in the cold weather.  This chemical is very much like anti-freeze.  The stems of the Goldenrod plant, along with the gall, dry and become brown.  Before winter, the larva creates a spring exit tunnel by eating almost to the surface of the gall.  It then returns to the center where it lays dormant during the winter.

Unless eaten by predators, such as other insects or birds, the larvae turn into grubs and then adult insects that will emerge next spring.  Many birds have learned to hunt for large galls in order to get a tasty meal.  Some fishermen are known to carry a few galls in their pocket and use large grubs as bait.

Two grubs living in a dormant gall.
There are two types of parasitic wasps Eurytoma gigantean and Eurystoma obtusiventris that steal the galls made by the Goldenrod Gall Flies.  These two wasps hunt for galls into which they lay their own eggs.  The Eurytoma obtusiventris lays its eggs inside the Gall Fly larva while the Eurytoma gigantean eats the whole gall fly and takes its place in the gall.  

Round galls are created by the Goldenrod Gall FLY, while elliptical galls are created by the Goldenrod Gall MOTH.  The moth's life cycle is much the same as that of the fly except that theie galls are more camouflaged and elongated. 

It should be noted that there are other causes of galls as well which include other parasites such as fungi, bacteria, insects and mites.

Fun Classroom Activity

Take your class for a walk to your local park, woodland or even hunt in the grasses alongside parking lots and shopping malls.  Goldenrod grow just about everywhere.  Have students search for and collect galls at various times of the year.

Look for mature, brown galls that do not have any exit holes.  This will ensure that the grub is still in the gall.  Cut open the galls and try to identify the insect species inhabiting its home.  

This is a great introduction or companion to teaching students about the various types of animal homes.  Photographs in this category can be found at Animal Homes.  Complement your lesson plan with a slide show on this same topic at Free Slide Presentations

Friday, 9 August 2013

Using Images to Enhance Student Learning

It’s an animal that’s about the size of a Loonie (that’s a Canadian dollar coin to you non-Canadians), but sometimes it can grow to be heavier than a small child.  It’s usually green, but some are also shades of brown and black.  Some are “painted” with a yellow streak.  It has small eyes and flaring nostrils along with four stout legs.
Do you know what animal I’m describing?  Neither might your child or a student.  If I further continue my description to include that on some species of this animal, its tail looks like that of a dinosaur, can you now guess the animal?  Probably not.
If, however, I were to post or show you a picture of the animal I was describing, I am sure that at any age, almost everyone would be able to identify it.   Perhaps not the specific scientific name of the animal, but you would certainly be able to identify the species.
Learning, at any age, takes repetition. Have you ever watched a young child watch the same video over and over until they “get” it?  My aged mother has to repeat a new telephone number many times before as she says “it sinks into my old brain”.  But repetition of the same method of learning is not as good as being exposed to new material or a new concept in a variety of ways.  Just as we use our senses of touch, taste and smell to identify a food, learning about new concept, or, in this case a new animal, is made easier by the use of a variety of teaching methods in order to comprehend and grasp the new idea. One of the best learning methods is visual – seeing a picture.
Compare my talking about a “Teasel”, to that of seeing a picture of one.  A Teasel, by the way, is a genus of a flowering plant in the Disacaceae family known as Dipsacus.  It’s an amazing specimen of plant with lavender flowers located on prickly heads that form on tall stems.  The plant blooms on the heads in an outward fashion resulting in what looks like a purple floral belt.  The flowers continue to open blooming towards the top and bottom of the head leaving a barren cone where the spent flowers were.  Get the idea?  I’ll bet an image would help?

Teasel (Teazel or Teazle)
Although rather pretty,
Dipsacus is considered an invasive species.

Have you ever wondered where the term “a picture is worth a thousand words” came from?  Believed to have come from an article written by Fred R. Barnard used to promote images in advertising, the phrase affirms that a visual image can easily take the place of a lengthy, textual description.
Educators, be they teachers or parents, are ever in search of images to enhance their lessons.  In fact, students also have a great need for photographs for school projects and assignments.  Neither has much time to spend on research nor wants to expend the effort it takes to register and become a member of a website only to get access to a limited amount of free materials.  Paying for image resources – have you seen a teacher’s budget or a student’s allowance lately? – is usually out of the question.  Cutting and pasting images from your search engine’s internet image search result pages may result in your using images that are copyrighted.  Such usage is the same as stealing the work of others.
Find good sites that offer free images, bookmark them and check often for new materials.  If you do find a website that offers free photographs, read the Terms of Use carefully.  Ensure they hold the copyrights to the images and be very sure you understand what you can and cannot do with the pictures.  Be aware of any restrictions or requirements there may be for you to use and download the photos.
The animal described above, by the way, was a snapping turtle.  The reference to “painted” is in relation to Northern Ontario’s wide-spread Painted Turtle species. 
Tiiu Roiser  BAA, BEd.
Classroom ideas:  Use images -- to decorate your classroom, make vocabulary flash cards, include in slide presentations, add to your handouts & worksheets, provide as a resource for your students, and as inspiration for art work.  Images can help to illustrate items and sentence structure for English as a Second Language (ESL) students and may assist them in expressing their needs.  Consider making a picture book for young students.
To enhance your lesson plans and/or student projects, you can download 100% free images from  There are no gimmicks and no registration is required.  Just follow the Terms of Use and download high resolution images and slide shows for use in the classroom.
The webmaster and owner of this blog is a retired teacher currently working with young children on a volunteer basis.  Although not a professional photographer, her work has been published on a variety of websites and some of her photographs are part of Environment Canada’s photo bank.  She has developed and maintains an educational website on which she freely shares her photographs and educational resources. 

Wednesday, 7 August 2013

Little Gobbling Larvae That Wreak Havoc Upon a Forest - The Gypsy Moth

While photographing lichens in Northern Ontario, a fuzzy brown patch upon the bark of a cedar tree caught my attention.  I thought I had come upon the nest of a spider. 

The fuzzy brown material I assumed was chewed pulp – quite possibly a nest made of chewed tree fibres, constructed much the same way that hornets chew plant materials for form their papery homes.  But the bark around the fuzzy patch was intact – from where had the spider gotten the material from which to build its nest?  I began to take note that a great many trees had similar patches on their trunks and I even found some patches on cement posts.  This was no spider nest!

Egg mass of the Gypsy Moth
on Poplar Tree
Thanks to the research of a Park naturalist at Grundy Lake Provincial Park in Northern Ontario, I learned that what I’d discovered was actually the egg mass of the Gypsy Moth [Lymantria dispar L.], also known as the European or North American Gypsy Moth.  According to the Ontario Hamilton Conservation Authority, the larvae of this species consumes the leaves of over 500 species of both deciduous and coniferous trees, shrubs and plants.  The starving larva move from tree to tree and are transported by wind currents.  
The Gypsy Moth was accidentally introduced to North America around 1868 in a failed attempt at starting a silk industry.  It first evolved in Europe and Asia .  The US Forest Service calls them one of North America ’s most devastating forest pests.  The Park was grateful for my discovery and concerned as to whether or not they had an epidemic on their hands. 

So what does a Gypsy Moth look like?  Adult males are a light brown and grey colour with a darker brown mottled pattern on their wings. The male has feathery brown antennae and a wingspan of just under 2 inches.  Females are slightly larger (2.5 inches) and are almost completely white in colour having a few dark-coloured stripes across her wings.  She has a light-coloured fuzzy head and has a few dark markings on her wings.  Females are flightless.
Round black eggs wrapped in the warmth of the
Female Moth's hair.
Reproducing once a year, females usually lay egg masses from late June through August on tree trucks, but have also been known to lay eggs on rocks, etc.  Each beige coloured egg mass that is about 304 cm long and 102 cm wide, contains about 100 – 1,500 eggs.  As the female lays the eggs, she covers them with hair that she pulls from her abdomen.  Protected by the warmth of the female’s hairs, the eggs remain in their mass over the winter and hatch in the late spring or early summer. The hair mixture also provides protection from predators.  A hatched egg mass is lighter in colour and has tiny exit holes on the surface.  The eggs will no longer be felt inside.


As they hatch from their tiny, dark-coloured eggs, the larva are about 3 mm in size, but will grow to be about 50 to 90 mm. The larvae go through several developmental stages and pupate in the late summer.  Males emerge first and begin to search for females.  After mating, both adults die.
Since my discovery, I have now further learned that adult Gypsy Moths only live about a week since they do not have an active digestive system.  While they can drink moisture, they cannot eat.
This species of Moth is particularly destructive because it causes havoc in a number of ways. Did you know, that one Gypsy Moth caterpillar can eat about one square meter of foliage?  Multiply that with an infestation and entire forests can be stripped of their leaves.  Defoliation causes a tree stress and weakens it.  After about two years, the tree can no longer produce its own energy and may die.  Many mature trees can be lost in this way.
What about the nuisance of something called caterpillar "frass"?  With the large amount of eating that they do, caterpillars also produce a lot of fecal matter, or "poop" called "frass".  In a large infestation, frass has been known to cover backyards, outdoor furniture, etc. decreasing a homeowner's enjoyment and use of their land.

How do you get rid of the Gypsy Moth?  
Hand picking the egg masses and spraying is done in an effort to rid an area of these pests.  While scraping egg masses off infested trees and the removal of caterpillars and pheromone traps work to some degree, often a biological pesticide called Bacillus thuringiensis kurstaki (Btk) is sprayed over large areas.  Made of a dormant bacteria that is toxic to Gypsy Moth caterpillars, this pesticide affects only this species and, although costly since it needs to be sprayed from the air, is very effective.

While taking photographs, I touched an egg mass quite a bit as I examined and rubbed off some hairs and vigorously rolled the eggs in my palms to reveal the black spheres.  After the fact, I’ve now learned that the fuzzy hairs that protect the egg mass can cause a serious rash if touched by bare skin.   Perhaps since it was spring, the potency of the irritant had decreased over the winter months, but luckily I did not experience any irritation or rash.  My advice should you find a Gypsy Moth egg mass, is that you not touch it for you may not be as lucky.

 Teaching ideas:

Introducing students to the Gypsy Moth works well with Ontario’s Elementary curriculum.  Teachers can stress how plants and animals are interdependent and are adapted to meet their needs from the resources available in their particular habitats.  Have students think about how might deforestation caused by the Gypsy Moth impact on the lives of other animals?  the forest?  the lumber industry?  recreation? 
Your discussion should progress to students getting an understanding of a community as a group of interacting species that share a common habitat.  How are communities affected by this moth?  What about a community dependent upon timber as their source of income?
Download these and other images of Gypsy Moths from  Check out the Insect Category where you can download free clip art to share what the male and female Gypsy Moth look like.
Further info:

CBC News - Helicopters to spray gypsy moth pesticide



Friday, 2 August 2013

Fabulous Fungi-Making Spore Prints

Marasmius rotula - "Pinwheel Mushroom"

I have recently become fascinated by the world of fungi, the study of which is called “mycology”.  I found some pretty mushrooms while walking through the woods, took a few shots and then tried to identify them.  That was it, my world was changed forever.  I now walk with my head down, peering into the damp forest underbrush, hoping to find elusive toothed fungi like Hericium coralloides - the Comb Tooth fungi or Hericium americanum with beautiful white cascading  hanging spines. 

Did you know, that fungi are organisms that are made up of networks of tiny, microscopic “threads” which spread themselves throughout the soil?  The individual threads are known as “hypha” and an entire network of hypha is called a “mycelium”.

The mycelium lives in the ground throughout the year, but when the conditions are right, the fungus will want to “bloom” in order to produce and disperse spores to produce new fungi.  The mushrooms we typically see coming out of the ground or growing from rotting timber are actually the fungi “blooming”.  We call these visible spore producing structures “fruiting bodies” or “sporocarps”.

Mycena leaiana
Little knots of hyphae begin to form under the ground and then grow into two parts:  the mushroom’s cap and the stem.  When the knots, called “primoridia” get large enough, the stem and cap get pushed above the ground and become visible to us.

Fruiting bodies grow in a wide variety of shapes, sizes and colours.  Some are quite ugly like the dark “Devil’s Urn” which is 12 cm tall and goblet-shaped, or the cute “Lemon Drops” which are small, bright, yellow 3 mm droplets.  There are some that look like orange peels, and the beautiful Amanita Muscaria with its red cap and white speckles.  Some even look like underwater coral! 

While the mycelium remains under the ground all year, the visible mushroom portions live for only a short while.  A single mycelium can produce many mushrooms.

Did you know, that fungi cannot manufacture their own food by means of photosynthesis and that they secrete an enzyme in order to digest parts of their surroundings?  Spores are produced on the “gills” that are typically under the “cap” of the mushroom.  A mushroom will grow tall on its stalk in order to raise its cap higher than its surroundings.  When the spores are released, they fall to the ground and are carried by breezes in the air.  The higher the cap, the further the spores can be dispersed.

Identification – With photos in hand, I began to leaf through mushroom identification books and Googled images for comparison, trying to put names to the specimens I'd found. What I found, however, was a whole new world and that proper identification by sight alone is impossible!  Two mushrooms may appear exactly alike with only very slight differences.  One may have a slight indentation in its cap that you may not notice.  The Lactarius and Russula genera are difficult to identify for even the expert fungus enthusiast.  Unlike the Russula, Lactarius mushrooms “bleed” a latex-like fluid.  While looking identical, one may emit a white latex from its gills while the other does not.  Some species look exactly alike except for the colour or pattern of their spores – identified by doing something called taking a spore print. 

I next learned that fungi can be grouped as Sac fungi, Earthballs, Puffballs, Jelly fungi, Stinkhorns, Morels, Corals, Toothed fungi, Brackets, and Boletes.  Spore prints may be pink, brown or light.  Herein I need to mention that there are also slime moulds (Myxomycota) and lichen… but that’s a topic for another day.

Fun Classroom Activity – Making Spore Prints

Making a spore print with your students is a great tactile addition to your fungus lesson plan.  You will need:
- fresh mushrooms – picked from the field, not the grocery store;
- a clear sheet of plastic; 
some type of covering – perhaps a bowl or glass.

Cut or pull off the stalk of the mushroom; place the cap on the sheet of clear plastic with the cap facing down; cover over night with a bowl.  If the mushroom is small, a cup or glass will do as well - I used plastic drinking glasses with my students. 
By the morning, the cap will have released its spores onto the plastic and you will see a colour and pattern.  A white sheet of paper works well too, unless your mushroom specimen happens to drop very light spores in which case you will be disappointed thinking you are seeing nothing and will assume this exercise didn't work. Unless you know ahead what colour spores your mushroom will drop, use clear plastic.

Note:  A mushroom will drop spores without the bowl being placed upon it, the bowl merely speeds up the process.

You need to explain to your class that a mushroom’s spores are microscopic and that normally you would not be able to see them.  You can see the pattern and colour of the spores since the mushroom is releasing millions of them! 


Note:  There are many toxic mushroom “look-alikes” that resemble edible ones.  You should under no circumstances rely upon my identification of species.  I am not a mycologist and have not done microscopic identification - I have added names to images which I merely THINK resemble the species.  Some mushrooms and fungi are DEADLY poisonous and their effects do not show up until it is too late to save yourself.
Resources for your fungi lessons:



Welcome to my rambling thoughts as I continue to expand my Teacher and Student image resource website at   I have shared some of my photographic experiences with others and it has been their desire that I share some of my learning adventures with the rest of you.  As I come upon more things I never knew, I'll share them with you.  If I add new image categories, I'll let you know.  If I find some great online materials that will be helpful to you in your teaching or learning, I'll post them for you.

If you have a burning desire to know more about me, visit my "About" page at, otherwise, let's get started....