Created: 9/30/2013 Updated: 8/9/2016
In the early 1900s, North America lost nearly every American Chestnut to the chestnut blight. My grandparents have likely never seen a mature one, though they are estimated to have numbered 3 billion. Most people of my generation have rarely if ever seen an American Elm, once an extremely widely-planted shade tree which was almost killed off by Dutch Elm Disease from the 1920s to 1970s (and beyond). Now it seems that my grandchildren may be lucky to see an ash tree on this continent, as the Emerald Ash Borer (EAB) threatens to wipe out the entire genus, Fraxinus.
The Emerald Ash Borer (Agrilus planipennis) was first discovered in North America in 2002, and since then has caused the death of around 40 million ash trees. While it seems to slightly prefer some ashes to others, it will attack any member of the genus. The beetle causes destruction in its larval phase, when it lives just under the outer bark and chews winding trails or “galleries” through the layer of tissue called phloem, which moves sugars from the leaves to the roots. Since the beetle lives under the bark, infestations can go unnoticed until the tree is visibly distressed.
Sprouts from the base are a common symptom
I saw this recently on the museum grounds. In an ash tree, sprouts from the base are a common symptom of EAB infestation. The phloem is so damaged the roots have all but stopped getting nutrition from the leaves, and the tree sends new shoots from below the damaged area. Clearly, these few sprouts won’t suffice, and by the time such sprouts appear it is usually too late to save the tree.
D-shaped hole of emerging beetle
A second sign presented itself with a closer look: the characteristic D-shaped hole where the adult beetle emerged. I saw around ten such holes on this tree. By prying some loose bark back with my knife I was able to catch a glimpse of the galleries left by the larvae.
Gallery or trails of larvae
The adults left to lay eggs on other nearby ash trees, of which there are plenty. 19% of the City of Chicago's trees are ashes, and there are an estimated half-million privately owned in the city.
So far, the only effective treatment has been systemic insecticides. They must be applied before an infestation occurs, must be re-applied every few years, save only the treated tree, and kill all the other insects which feed on ash trees. Because of the expense and complications involved, only certain "high-value" trees are being treated, and most agencies prepare for the EAB’s arrival by replacing ashes with other trees. The EAB has a limited range and moves slowly, so it may be possible to impede its spread by treating and/or removing trees in areas not yet affected, in a strategy similar to a fire-break.
Even if you don’t own or manage ash trees, you can still help. Always use locally-sourced firewood, so if any EAB larvae or adults are in the wood they stay in an already-infested area instead of being driven somewhere that had yet to be affected. It is likely that the original U.S. infestation was a small number of individual insects that arrived in wooden packing crates from Asia, where the insect is a minor pest. The cost of removing or replacing or treating trees could well run into the billions of dollars-- largely taxpayer dollars as governments manage large ash populations and dead trees cause hazards in populated areas-- so it is best for everyone if we leave wood where we find it and do what we can to limit the spread of this invasive species.
Trust me, I wish I could end on a hopeful note, or even just give a spoonful of sugar with this bitter pill, but the destruction caused by invasive species far exceeds the limited resources of time, money, and personnel available to combat them. With luck, the EAB won’t kill all 2 billion ash trees and we’ll still have some for our grandchildren to appreciate, but now would probably be a good time for you to get to know the ashes in your area, whether the EAB is already present, and who to call if you spot damage in unaffected areas.
Andrew WunschelView Comments
Created: 9/30/2013 Updated: 8/9/2016
Throughout the ages, butterflies have been symbolically important to many cultures, representing everything from the souls of the dead, to resurrection, to steadfast love. Their true stories of survival in the natural world are no less meaningful, but often go largely unnoticed. So I was grateful and excited when the cast of Steppenwolf Theater’s current production of “The Wheel” wanted to ask about the real butterflies behind the imagery and references in this play.
Here is a sampling of questions I was more than happy to answer:
What is the source of butterflies’ color?
- Mostly light refracting off the scales of their wings.
How long does the entire life cycle take to complete?
- Frequently as long as a year, though some adult stages may only last for two weeks.
How do butterflies make it through the winter in Illinois?
- Depending on the species, they may overwinter as adults, larvae, eggs, or chrysalises. A well-known exception is the Monarch, which flies away to warmer climates.
Do butterfly species have “personalities”?
- They have field behaviors that are unique and help with their identification, such as flight patterns (flap, flap, glide for the monarch), or territorial dog fighting amongst male skippers.
We observed a sample of the stunning tropical species on display in our Haven (such as the Swallowtail Ulysses butterfly or Blue Mountain Butterfly, Papilio ulysses from Australia, one of my favorites) and talked about some of the unique plant/habitat/insect interactions that occur around the world. What became clear as we discussed the physical progression from egg, to caterpillar, to chrysalis, to adult is just how perilous a journey it is – not unlike the journey that occurs in the play itself. Much of the cast was unaware of just how much trouble certain butterfly species are in around the country.
Blue Emperor Swallowtail
We discussed the tiny but elegant Swamp Metalmark Calephelis muticum that used to fly (and as of this summer’s work, may again establish) in Illinois. It is startling in its small size– a stark size contrast to the giant Ulysses but still an incredible beauty. The story of its loss is one of human imposed challenges.
Butterflies have endured the ever-revolving cycles of life and abundance for thousands of years, but are now facing new, manmade challenges. How butterflies and other species might respond to these changes was a topic of discussion and inspiration for the cast members.
It was a great afternoon, and I was left feeling grateful that although we have come far in our understanding of the processes behind it all, our love of the magic of nature still inspires artists and scientists alike. Watching the drama of nature play out is never boring, with plot twists and surprises to keep you at the edge of your seat. And the best thing is, we all have a role to play.View Comments
Created: 9/12/2013 Updated: 8/9/2016
Our Blanding’s project deals with several hundred turtles in numerous different locations and if we are not careful, the individual identities of the turtles can quickly get mixed up. So how do we stop that happening? Those of you who are dog owners are probably already familiar with ID chips. We use a very similar thing for our turtles.
These are the tools we use. The ID chip is about the size of a grain of rice, the syringe has a hollow tip to hold the chip and the tweezers hold the skin of the turtle as the chip is inserted. The turtles’ skin is quite loose just in front of the hind leg so this is the location of choice for inserting the chip. As with anything slightly invasive that has to be done to a turtle you get one chance only! One chance to grab the leg before it is pulled firmly into the shell and one chance to get hold of the skin before the turtle clenches up and that loose skin miraculously disappears!
Luckily for us it appears the turtle doesn’t bear a grudge for long so if we miss at the first attempt, we put the turtle back into the water, go on to the next one and then come back to the original turtle to insert the chip. Once the chip is inserted we scan the turtle and read off the ID number. This is a multi digit and letter sequence that will immediately let us know which turtle we are working with.
Some of our turtles go directly from the museum out into the wild but we can’t afford to put radio transmitters on all of them so this is a great way of knowing which turtle is which should we come across them a few years later. This is such a precious species, we want to be able to use as much data as possible when we find an individual so being able to identify them, of course, is vital.View Comments
Subscribe to the Nature Museum blog and never miss a post!
Created: 9/5/2013 Updated: 2/16/2017
Wondering how to green-up your clean-up? Join us on Wednesday, September 11th from 6-7pm for Green Cleaning 101! In this one hour workshop, you’ll learn the basics of green cleaning for your home and make a starter kit so that you can get cleaning right away- no excuses!
Green Cleaning 101 has been held at the Nature Museum since 2010. Over the past three years, many people have taken the class, including some of our Nature Museum volunteers. Walt Mellens has been a Nature Museum volunteer for three and a half years, and took the class with his wife. Here’s what Walt has to say about his experience with the class:
“We took the Green Cleaning 101 Class at the Museum and what a difference it made! Previously we were purchasing 'green' cleaning products at a premium price, and unhappy with the efficacy of them. Now we make our own cleaning products for pennies, and we are constantly impressed with the results! We have a clean home, a green home, and no chemicals in the air we breathe! Thank you!”
Green Cleaning 101 ingredients
Ready to get started? The class is only $10/members, $15/non-members and includes all materials, even a bucket to lug everything home! Register online at naturemuseum.org (click the date on the online calendar for the registration link) or call 773-755-5122.
We hope that you can join us!
Heather GranceView Comments
Manager of Public Programs