Photo of the Week – September 2, 2011

I photographed this bee in late August of 2009 in a restored (reconstructed) prairie.  At the time, I naively assumed it was a honey bee – not knowing much about bee identification.  I stuck to that assumption a year later when a version of the photo was used on the cover of NEBRASKAland magazine.

Native bee on pitcher sage (Salvia azurea) in restored prairie at the Deep Well Wildlife Management Area near Phillips, Nebraska.

Then, in August of this year, I was giving a presentation to staff of the Missouri Department of Conservation (MDC) about prairie ecology, and I used my “honey bee” photo as part of a slide on the decline of honey bees and the need for a strong community of native bees to pick up the slack.  As I was talking, I glanced over at Mike Arduser, a natural heritage biologist – and bee expert – with MDC and noticed that he had a pained expression on his face.  Knowing I was in trouble, I stopped and asked him what I’d said.

Mike explained that the bee in the photo is actually the native bee, Tetraloniella cressoniana, that feeds only on the pollen of pitcher sage (Salvia azurea) – the plant I photographed it on.  So – far from being a social generalist feeder like a honey bee, this bee is an example of the other extreme.  A specialist bee that relies on pollen from only a single plant species.  How great is that!

Apart from my chagrin about calling it a honey bee, knowing the real story about this bee makes me like the photo even more.  The fact that the photo was taken in a location where cropland had been converted to high-diversity prairie – and there is no other prairie nearby – makes it even more interesting.  I’d love to know how this bee managed to find and nest in/near a prairie that contains pitcher sage.  Where did the bee come from?  Did it search randomly, or does it have a way to “smell” or otherwise sense this plant species?  What a fun thing to think about!

The above photo wasn’t taken in one of our Platte River Prairies, but I’m sure hoping to find Tetraloniella there this fall.  Pitcher sage just started blooming a week or so ago and I’ve been out looking a couple times.  So far, no luck.  I did find a bee with a similar color and striping pattern, but it turned out to be the other species of bee Mike said I’d likely find using pitcher sage (don’t you love experts!).  So I’m still looking… 

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Lady’s Tresses Orchids in Prairie Seedings

I love mysteries. 

I don’t know much about orchids, but my understanding is that they can be difficult to establish in restored (reconstructed) prairie, largely because they rely on mycorrhizal fungi that are unlikely to be present in soils after years of row crop agriculture.  Regardless of that information, or maybe because of it, (I can be somewhat obstinate) we keep harvesting seed from nodding lady’s tresses orchids (Spiranthes cernua) whenever we can find the plants after they’ve gone to seed in the fall. 

…and darned if they’re not showing up in our prairie seedings!  To date, I’ve found Spiranthes in at least four separate prairie seedings in our Platte River Prairies.  When I saw the first plant, I came up with all kinds of explanations for how it might have occurred, none of which included our seed (there was some bulldozer activity near where the plant was, so surely some plant material and soil came in with the dozer…).  By the third and fourth sites, though, I finally came around to the idea that the plants had to be a result of our seed.  I’m still not sure of that, but it’s pretty hard to think of other reasonable explanations.

We've found nodding lady's tresses plants like this one in at least four prairie seedings now. Those seedings were planted in 1995, 1995, 1997, and 1999, respectively.

So – what’s going on?  Is there something special about the sandy loam soils that allowed myccorhizal fungi to survive many decades of row crop agriculture?  Are those fungi somehow making their way into the soils once prairie vegetation establishes?  Are orchids less reliant on those fungi than we thought – or maybe just able to use a wider variety of fungi species than we thought?

I don’t have any answers, just lots of questions.  I’m hoping to hear from some of you about your experiences with Spiranthes species in prairie seedings.  I’m also hoping that some of you know more about myccorhizal fungi than I do (I still have to check the spelling every time I type it…) and can explain what I’m seeing.

Help?