Gossamer Tapestry

Reflections on conservation, butterflies, and ecology in the nation's heartland

Monday, June 25, 2007

Yet Another Weedy Enemy

Summers at Bluff Spring Fen mean lots of weed control. There are many invasive species that would overrun the preserve given half a chance. This year, we have discovered a new problem: a large stand of nodding thistle at the far east end of the preserve. The thistles are not in an area that we are actively managing. Still we worry that the light, fluffy seeds will blow into important parts of the preserve, so Leon and I went out over the weekend to do battle.

Nodding Thistle

The thistles are insidious. Even if you cut them down, the flowers can still complete their development and produce viable seed. So we go through the stand, cutting and bagging all of the flower heads. These get thrown into a pond that was created decades ago as part of a gravel mining operation. Then we go back and cut down the stalks, which can produce more blooms. Finally spritz the cut edge of the stem with herbicide, which will kill the roots.

Strangalia solitaria

While engaged in thistle control, I found a beautiful flower-feeding longhorn beetle called Strangalia solitaria. It took me a moment to recognize it, because it’s superficially similar to a related species, Typocerus octonoatus, that is common on site. I managed to get a nice shot of a Typocerus for comparison. Note that the end of the abdomen tapers much more in Strangalia than it does in Typocerus.

Typocerus octonotatus

While out and about, I also got some shots of a nice buprestid beetle. Tropical buprestids can be larger than my thumb, and beautifully metallic. They are among the most beautiful insects in the world. I’m happy that I got its photo. This is a species that I collected along railroad tracks lasts year. I don’t know what it is, nor do I have a good key to local buprestids. Now I can post the picture on my favorite online insect identification site. Perhaps I’ll get an ID.

The mystery buprestid
Update: the mystery buprestid is Acmaeodera pulchella

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At 16:06, Anonymous Mark H said...

Dr. Taron: HEY.....our climates DO match in some ways. Our entire Skyline neighbors banded together to fight Garlic Mustard and pulled, bagged, carted to one sight over 10 tons of the stuff. We figure ONE more spring, and we may have almost all of it gone. That can do what thistles do after being pulled...produce viable seed. YES, insidious is the right word. Once again, we're sharing the same issues. ***BY THE WAY....I added to your comment on the pickles and WILL be posting that recipe very soon (WE will begin making pickles in a couple of weeks).......yeah! Glad Leon's enjoying that last one....hah hah.

At 17:04, Blogger robin andrea said...

I was really surprised to find that thistle will still produce seed even after its been cut down. That's a very interesting reproductive strategy. We put a bunch of cut thistle into a box, closed the lid and waited. After several months, the thistle itself had dried and shrunk to practically nothing, but the seeds nearly filled the box.

Great beetles, love those longhorns.

At 17:32, Blogger Dave said...

Off subject, but I have a bug question! Today while on a tree survey I saw these skinny metallic green damselflies (?) with soild black wings. There were a few of them engaged in what looked like a drunken dogfight over the little creek that went through the property. I've only seen them a couple times before - they seem to like water? They're really cool looking, and I was hoping you'd know what they are?

At 19:17, Anonymous Lemuel said...

I should have you come and assess the weeding of my new "south 40". Although I have not yet seen any thistle.

At 19:18, Anonymous rcwbiologist said...

Geez, I'm glad we don't have that plant on any of the properties I've worked on. What a pain!

At 22:31, Blogger Ur-spo said...

nasty things; invasive species; but I admire their cheek.

At 08:07, Blogger Doug Taron said...

Mark- Yeah, we have to remove the garlic mustard, too. It seems like we've been working on it for decades.

Robin- Your experiment illustrates the problem beautifully

Dave- Your damselflies are ebony jewelwings (Calopteryx maculata. They are one of my favorites. We put them in our butterfly exhibit sometimes.

Lemuel- Thistles are nearly ubiquitous. My guess is that sooner or later they will show up.

RCW- True, but then your sites have their won charm, as I'm sure you can attest.

Spo- Come on out to the fen and help with weed control some time. Then we'll see how much you admire their cheek.

At 12:59, Blogger rodger said...

Mark is known to wander the neighborhood with shovel in hand searching for thistle and scotch broom. He is the "Hamlet (as our neighborhood is known) Hunter" when it comes to non-native, invasive species.

And...although the thistle is nasty, it is also very beautiful! Like so many poisonous critters.

At 02:58, Blogger Tony said...

But Doug....
Just like I told you when I said hello in person at the museum for the first time. Where else does one get to maintain a "front yard' like yours and not have it called a weed patch. LOL. Hope all is well..thanks so much for all your hospitality the day I visited. enjoyed it immensely.

Back blogging again.

At 19:06, Blogger Dave said...

Doug -

Thx for the ID! It's a really cool insect. I'm curious as to it's rarity. I have only seen them a couple times near creeks - never near larger rivers, etc.

At 17:21, Blogger Doug Taron said...

Rodger- I'm so glad we don't have Scotch broom in Chicago

Tony- I enjoyed meeting you, also. We'll have to do it again.

Dave- Ebony jewelwings do prefer smaller creeks. They also show a preference for habitat that is at least partly shady. They are a very common Chicago area species, but you have to look in the right spot.

At 17:24, Blogger Texas Travelers said...

I assume this is the buprestid to which you referred. It's a nice looking bug. I am really looking forward to finding some nice bugs this summer. Not looking forward to the Texas heat though.

Thanks for the visit.

Have a great week,


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