Photo of the Week – July 30, 2015

During our trip to the Grassland Restoration Network workshop in Minnesota last week, several of us got up early enough to catch sunrise at The Nature Conservancy’s Bluestem Prairie on two beautiful mornings.  I shared a few photos from those outings last week, but thought I’d post a few more today.  I’ve got lots more…it wasn’t hard to find subject matter to photograph!

Leadplant and wildflowers.  TNC Bluestem Prairie, Minnesota.

Leadplant (Amorpha canescens) and other wildflowers abound on The Nature Conservancy’s Bluestem Prairie near Glyndon, Minnesota.

Woundwort (Stachys palustris).

Marsh hedge nettle, aka woundwort (Stachys palustris).

The cool dewy morning allowed me to get pretty close to this resting monarch butterfly...

The cool dewy morning allowed me to get pretty close to this roosting monarch butterfly…

Beetle on Flodman's thistle.  TNC Bluestem Prairie, Minnesota.

This beetle was feeding its way across the top of this Flodman’s thistle (Cirsium flodmanii) – at least I think that’s what I think the thistle species was… it’s always dangerous to guess when I’m far from home.

Common milkweed.  The Nature Conservancy's Bluestem Prairie - Minnesota.

Common milkweed flower buds can be just as attractive as the open flowers…

Bee on milkweed.  TNC Bluestem Prairie, Minnesota.

This bee spent the night on a milkweed leaf and wasn’t quite warm and dry enough to fly off when I spotted it.  If you look carefully, you can see pollinia stuck on two (maybe three?) of its feet.  If you’re not familiar with the fascinating (and unlikely) story of how milkweed is pollinated, you can learn more here.

Purple coneflower (Echinacea angustifolia).  The Nature Conservancy's Bluestem Prairie - Minnesota.

Purple coneflower (Echinacea angustifolia).  This is a species we don’t find very often in the Platte River Prairies (though it’s fairly common nearby) so I always enjoy seeing and photographing it when I can.  As with other “composite” flowers, coneflowers are actually collections (composites) of two kinds of flowers – the ray flowers that look like petals and the disk flowers in the center.  Occasionally, as in this case, a genetic signal gets crossed and ray flower pops up where a disk flower should be.

If you find yourself traveling to or through northwestern Minnesota (just east of Fargo, ND), I encourage you to make the time to visit Bluestem Prairie Scientific and Natural Area.  You can find directions and more information on the site here.  The Nature Conservancy owns about 6,000 acres of prairie there, and their ownership is bolstered by several other tracts of conservation land right next door.  The prairie hosts nesting prairie chickens and beautiful tracts of northern tallgrass prairie.  It’s worth the trip to see it.

A Hole New Mystery to Consider

On my last trip to the Niobrara Valley Preserve, I photographed the bark of wildfire-killed pine trees in warm late day light.  I liked both the patterns and the color and was just trying to make some visually-interesting images.  As I was taking the photos, I saw numerous small holes in the trees but didn’t think much about them.  Holes in dead trees are not really unusual, after all.  Upon looking at the photos later, however, I noticed something intriguing – many of the holes seemed to have a funnel shape, or beveled edge, at the surface of the tree.

Beveled

Tiny holes in the bark of a standing dead ponderosa pine tree killed by a 2012 wildfire.  The two near the center of the image have a funnel-shaped or beveled edge to them.  The Nature Conservancy’s Niobrara Valley Preserve, Nebraska.

I couldn’t come up with a good explanation for that beveling, so I did what I usually do when I can’t identify something – I sent the photos to people with more expertise and begged for help.  Ted MacRae was kind enough to respond that except for the flared ends, the perfectly round holes might have been created by adult pine sawyers (Monochamus spp.).  James Trager liked my speculation that perhaps something like a woodpecker might have chipped away at the holes, looking for an invertebrate meal, and added nuthatches and chickadees as other options.  But none of us have a good answer.

After hearing back from Ted and James, I looked more closely at other photos from that evening and noticed something else that might or might not be a useful clue.  Not only had the edges of some of the holes been chipped (?) away, but there were similar marks elsewhere on the bark.  I’m not sure if those are related to what happened around the margins of the holes or not.  In the photo below, look at the “pitting” – especially in the top left quarter of the image.

More holes in trees.

More holes in trees, along with tiny chipped or pitted marks, both around the insect(?) holes and elsewhere.

Is some creature (bird?  insect?  microbe?)  chipping away at the tree?  If so, why?  And is that creature chipping away at the edges of holes made by beetles too?  And if so, WHY?  Or, are the beveled edges of the round holes a separate phenomenon from the pitted surface of the bark elsewhere?

I guess it’s good for my brain’s health to ponder mysteries like this, and it’s fun to think through all the possibilities.  On the other hand, it would also be fun to KNOW WHAT THE HECK IS HAPPENING HERE, so if you have good theories – or even better, actual answers – please let me know!

I didn’t measure the holes, so I hesitate to give estimates of their size, but they were really small.  Maybe 3-4 mm across?  I didn’t give that info to Ted (but I should have), and I’m wondering now whether the holes were actually too small for pine sawyer beetles.

Help?