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Re: [beemonitoring] L. chrysurus - Roberts article‏

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  • Joe Metzger
    I think I can give you an explanation as to why the bees are found along railroad corridors. I m assuming the term oligolectic means they only (or primarily)
    Message 1 of 2 , Apr 12, 2008
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                I think I can give you an explanation as to why the bees are found along railroad corridors. I'm assuming the term oligolectic means they only (or primarily) collect pollen from species of the genus Centaurea. In areas where railroad tracks go through dry habitat, it is common for members of this genus to grow in the area next to the tracks. It seems to prefer this dry, open habitat. The railroad companies often use herbicide sprayed from the trains to keep down plant growth and since most of the species in the genus are either fast growing annuals or biennials, they can re-establish quickly if one group is wiped out by the spraying. There is a railroad track near Point of Rocks, MD, on MD 77 between Westminster and Thurmont (Thurmont is at the base of Catoctin Mountain in the Blue Ridge) where I have observed Centaurea spp. growing. I've never bothered to confirm its identity but I think it's C. maculata.
       
                                                        Joe Metzger


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    • Matthew Sarver
      I agree with Joe. C. maculosa seems to love railroad ballast throughout its eastern range. I imagine the tolerance to xeric conditions, combined with its
      Message 2 of 2 , Apr 12, 2008
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        I agree with Joe.  C. maculosa seems to love railroad ballast throughout its eastern range.  I imagine the tolerance to xeric conditions, combined with its allelopathic properties allow it to do very well in these areas.  I'll never forget gathering knapweed from a railroad bed along a New York lakeshore in extremely high winds one time.  The stuff was prolific there, and the wind allowed one to chuck the pulled plants up into the air where they were swept rapidly against a nearby chain link fence and pinned four or five feet up against the fencing for subsequent convenient collection in wildly flapping garbage bags.
         
        It's an excellent bee plant, unfortunately.  I have been pulling blooming plants in an effort to eradicate a small population of it on a shale road side on my property in western Pennsylvania.  This past year, my plants were literally covered in Bombus on the day I was working.  I actually got stung once or twice by grabbing a bee along with the stem I was pulling.  A late day rainshower had put most of the bees down and they settled in the knapweed foliage.  The bumblebees were going for a ride as I tossed the knapweed plants into piles on the roadside!
         
        I felt really bad about eradicating this obviously excellent food source, at a time when bees were using it so heavily.  I did leave the piles of knapweed out to dry on the roadside, so that the bees could take advantage of whatever nectar and/or pollen remained in the flowers that were still accessible, before they wilted.  After the plants had dried and there was no longer any chance of killing bees, I finally bagged up and removed the material.
         
        At any rate - it sounds like a focused knapweed effort is in order in the immediate vicinity of the Lithurgus sightings to reduce potential spread.  I wonder if there are local groups who might start to tackle this?
         
        -Matt


        From: beemonitoring@yahoogroups.com [mailto:beemonitoring@yahoogroups.com] On Behalf Of Joe Metzger
        Sent: Saturday, April 12, 2008 7:39 AM
        To: beemonitoring@yahoogroups.com
        Subject: Re: [beemonitoring] L. chrysurus - Roberts article‏

                  I think I can give you an explanation as to why the bees are found along railroad corridors. I'm assuming the term oligolectic means they only (or primarily) collect pollen from species of the genus Centaurea. In areas where railroad tracks go through dry habitat, it is common for members of this genus to grow in the area next to the tracks. It seems to prefer this dry, open habitat. The railroad companies often use herbicide sprayed from the trains to keep down plant growth and since most of the species in the genus are either fast growing annuals or biennials, they can re-establish quickly if one group is wiped out by the spraying. There is a railroad track near Point of Rocks, MD, on MD 77 between Westminster and Thurmont (Thurmont is at the base of Catoctin Mountain in the Blue Ridge) where I have observed Centaurea spp. growing. I've never bothered to confirm its identity but I think it's C. maculata.
         
                                                          Joe Metzger


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