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Re: [beemonitoring] Osmia chalybea - Thistle Food Plant

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  • Liz Day
    ... Yes! Bumblebees seem to be very attracted to the non-native thistles as well as the native ones. I feel it is a mistake to eradicate them all when no
    Message 1 of 3 , Jun 4, 2011
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      > One wonders if O. texana is feeding on the late season native thistles....as the 2 are very similar but temporally apart, if so it apparently does not benefit by the presence of non-native thistle/pests such as bull-thistles.  

      >Here lies another argument for resurrecting our native thistles from the hate pile.  C. horridulum is quite a lovely low growing plant and I have an equally lovely C. discolor.....

      Yes!

      Bumblebees seem to be very attracted to the non-native thistles as well as the native ones. I feel it is a mistake to eradicate them all when no comparable food source is present to take their place.

      Liz Day
      Indianapolis
      east-central USA
    • RestoreHabitat@aol.com
      Thanks to everyone for the well-deserved recognition of this critically important genus of our native flora. We are currently propagating all native thistles
      Message 2 of 3 , Jun 4, 2011
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        Thanks to everyone for the well-deserved recognition of this critically important genus of our native flora.
        We are currently propagating all native thistles (allowable) and establishing them as a substantial component of our habitat restoration projects for
        pollinators.
        Soon on the heels of C. horridulum, we have Cirsium pumilum-the second of our earliest blooming thistles here in the east. Everywhere that I have observed the
        the remarkably large blooms of C. pumilum- there appear bee parties of multiple genera on this sweet-smelling cloud of pink temptation.
        Cirsium hillii-federally endangered, I believe, is the important Midwestern cousin to our C. pumilum here in the East.
        Sadly, the two non-native biocontrols intended to control non-native thistles (Carduus and C. Vulgare) have been shown to have a devastating impact on the
        ability of our native species of Cirsium to reproduce--sad especially since our native Cirsium are such an important part of our flora and ecosystem. Larinus planus- a non-native thistle flower weevil, was observed actively feeding on native thistle as late as September of last year.
        Their activity begins in April/May in many parts of the country
        Any that have spent field time observing Bombus species will recognize the importance and value of our native Cirsium species.
        Randy Pheobus
        Native Grassland Conservancy




        -----Original Message-----
        From: sdroege@...
        To: beemonitoring
        Sent: Sat, Jun 4, 2011 10:46 am
        Subject: [beemonitoring] Osmia chalybea - Thistle Food Plant

         

        All

        Yesterday I stopped by the Isle of Wight, which is an island in the Back Bay of Fenwick Island which houses Ocean City on the coast of Maryland and collected two O. chalybea on Cirsium horridulum.  I was struck that both Osmia specimens were on the only C. horridulum around and how this plant is usually associated with sand, relatively rare and coastal, and had the potential to be a primary food plant for this species.  I also note that John Ascher has a picture of this species of bee on a Thistle in Florida (http://www.discoverlife.org/IM/I_JSA/0009/640/Osmia_chalybea,I_JSA910.jpg) but I am not sure if the thistle species is C. horridulum or not.

        C. horridulum is also the earliest blooming thistle in this region.

        Below is the distribution of the plant


        and here is the distribution of this uncommonly encountered bee (with some mixup with O. texana likely) and a showing of the general lack of collecting along the coast for bees.



        So, for those of you near C. horridulum you may want to swing some nets over the next few days as they were in full flower.

        One wonders if O. texana is feeding on the late season native thistles....as the 2 are very similar but temporally apart, if so it apparently does not benefit by the presence of non-native thistle/pests such as bull-thistles.  

        Here lies another argument for resurrecting our native thistles from the hate pile.  C. horridulum is quite a lovely low growing plant and I have an equally lovely C. discolor that Randy Pheobus gave me this is a spectacular addition to my garden.

        sam

                                                       
        Sam Droege  sdroege@...                      
        w 301-497-5840 h 301-390-7759 fax 301-497-5624
        USGS Patuxent Wildlife Research Center
        BARC-EAST, BLDG 308, RM 124 10300 Balt. Ave., Beltsville, MD  20705
        Http://www.pwrc.usgs.gov

        Those old days when the balancing of a
                yellow butterfly o'er a thistle bloom
        Was spiritual food and lodging for the
                whole afternoon.
              - Lowell

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