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Re: [beemonitoring] Divining the floristic record of Bee Specimens

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  • Doug Yanega
    ... Washing and cleaning of bees is a relatively recent technique. Old museum specimens of female bees often still have full scopal loads. Good collectors
    Message 1 of 7 , Feb 8, 2010
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      Re: [beemonitoring] Divining the floristic record of B
      Randy Pheobus wrote:

                  The subject of bee phenology and Redbud is an excellent introduction to two questions, the answers for which I am seeking some assistance:
      • First question:  Would sampling of native bee specimens collected historically have the potential to reveal the species of pollen (and, therefore, the flora) from which they themselves were collecting when they were collected? I am not sufficiently familiar with methods of specimen collection to know if, historically, collection of species entailed netting and pinning but little else that would eliminate the pollen record that the specimen contained. Obviously, washed bees would not contain the information that I am seeking. My research to support restoration efforts has revealed substantial declines in nectar and pollen producing flora native to this region and to which our native pollinators are so well adapted.

      Washing and cleaning of bees is a relatively recent technique. Old museum specimens of female bees often still have full scopal loads. Good collectors would have noted the host plant, but there is still hope of IDing mystery pollen. That being said, it IS a lot of work to glean and ID old pollen; palynological prep techniques involving slide mounts are often poorly-suited to processing such tiny amounts of pollen, while SEM photos can be time-consuming and expensive. I've tried both, and didn't find it to be very encouraging when imagining extrapolating the process to thousands of pinned specimens. A quick and easy technique for IDing old dry scopal loads should be the next of Sam's video tutorials! ;-)

      Peace,
      --

      Doug Yanega        Dept. of Entomology         Entomology Research Museum
      Univ. of California, Riverside, CA 92521-0314        skype: dyanega
      phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
                   http://cache.ucr.edu/~heraty/yanega.html
        "There are some enterprises in which a careful disorderliness
              is the true method" - Herman Melville, Moby Dick, Chap. 82
    • Cory Sheffield
      Hi Doug et al, One possibility that may soon be a reality (as right now it is very expensive) is the use of DNA barcoding (of sorts...different genes than used
      Message 2 of 7 , Feb 8, 2010
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        Hi Doug et al,

        One possibility that may soon be a reality (as right now it is very expensive) is the use of DNA barcoding (of sorts...different genes than used for insects) to identify pollen on bees.  Apparently, this is a way to not only quantify type and the amount of pollen in a scopal load. I dont know if it would work old very old specimens, but someone did get viable DNA from a moth collected by Alfred Russell Wallace.  Of course, this would involve population a database with known pollens...which may be a worthwhile project at some point.  The technique for pollen looked promising at a recent Barcodes of Life meeting in Mexico.

        Cheers
        Cory


        From: Doug Yanega <dyanega@...>
        To: beemonitoring@yahoogroups.com
        Sent: Mon, February 8, 2010 9:25:51 PM
        Subject: Re: [beemonitoring] Divining the floristic record of Bee Specimens

         

        Randy Pheobus wrote:

                    The subject of bee phenology and Redbud is an excellent introduction to two questions, the answers for which I am seeking some assistance:
        • First question:  Would sampling of native bee specimens collected historically have the potential to reveal the species of pollen (and, therefore, the flora) from which they themselves were collecting when they were collected? I am not sufficiently familiar with methods of specimen collection to know if, historically, collection of species entailed netting and pinning but little else that would eliminate the pollen record that the specimen contained. Obviously, washed bees would not contain the information that I am seeking. My research to support restoration efforts has revealed substantial declines in nectar and pollen producing flora native to this region and to which our native pollinators are so well adapted.

        Washing and cleaning of bees is a relatively recent technique. Old museum specimens of female bees often still have full scopal loads. Good collectors would have noted the host plant, but there is still hope of IDing mystery pollen. That being said, it IS a lot of work to glean and ID old pollen; palynological prep techniques involving slide mounts are often poorly-suited to processing such tiny amounts of pollen, while SEM photos can be time-consuming and expensive. I've tried both, and didn't find it to be very encouraging when imagining extrapolating the process to thousands of pinned specimens. A quick and easy technique for IDing old dry scopal loads should be the next of Sam's video tutorials! ;-)

        Peace,
        --

        Doug Yanega        Dept. of Entomology         Entomology Research Museum
        Univ. of California, Riverside, CA 92521-0314        skype: dyanega
        phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
                     http://cache. ucr.edu/~ heraty/yanega. html
          "There are some enterprises in which a careful disorderliness
                is the true method" - Herman Melville, Moby Dick, Chap. 82


        Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail
      • Jack Neff
        All: I would not be so negative about analyzing past dietary patterns from old pollen, at least for local faunas. Extracting pollen from pinned specimens is
        Message 3 of 7 , Feb 9, 2010
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          All:  I would not be so negative about analyzing past dietary patterns from old pollen, at least for local faunas.  Extracting pollen from pinned specimens is easy (assuming they haven't been subjected to the current fad for specimen washing) and there are several methods available from the literature (Dafni et al, 2005; Kearns and Inouye, 1993).  Many pollens are quite distinctive and can be identified without any special preparation beyond staining, at least if one knows the local possibilities.  More nondescript pollen may require acetolysis, a nasty involved process.  SEM works exceedingly well but can be expensive if your institution does not have its own machine.  The key is having a good local reference collection for comparison purposes.  Identifying pollen from samples from across a broad area (the entire Great Plains) is much more problematic.   Identifying unknown pollens from an unknown flora can be extremely frustrating for the non-palynologist, and often isn't a snap even for the professional.

          best

          Jack


          John L. Neff
          Central Texas Melittological Institute
          7307 Running Rope
          Austin,TX 78731 USA
          512-345-7219



          From: "RestoreHabitat@..." <RestoreHabitat@...>
          To: beemonitoring@yahoogroups.com
          Sent: Mon, February 8, 2010 8:15:28 PM
          Subject: Re: [beemonitoring] Divining the floristic record of Bee Specimens

           

           
           
          To All
                     
                      The subject of bee phenology and Redbud is an excellent introduction to two questions, the answers for which I am seeking some assistance:
          • First question:  Would sampling of native bee specimens collected historically have the potential to reveal the species of pollen (and, therefore, the flora) from which they themselves were collecting when they were collected? I am not sufficiently familiar with methods of specimen collection to know if, historically, collection of species entailed netting and pinning but little else that would eliminate the pollen record that the specimen contained. Obviously, washed bees would not contain the information that I am seeking. My research to support restoration efforts has revealed substantial declines in nectar and pollen producing flora native to this region and to which our native pollinators are so well adapted.
          • That leads to the second question:  Has there been observed a measurable decline in the size of adult native bees (Bombus is a good example) during certain portions of their pollen and nectar gathering season over the past few decades? Recently, field observations have shown a remarkable decrease in the size of workers toward the end of the season. Does anyone have any information or guidance on data that would indicate whether this is typical, as observed historically; or, perhaps, a more modern development?
                   These data will assist in creating a comprehensive plan for restoration of heliophilic habitat that will support the greatest diversity of both native floral and fauna.
           
                          Randy Pheobus, President
                              Native Grassland Conservancy
                                  301-440-8915
                      

        • Peter Bernhardt
          Dear Colleagues: Dr. Neff is taking us into a sensitive area. The fact remains that the majority of American pollination biologists still refuse to identify
          Message 4 of 7 , Feb 9, 2010
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            Dear Colleagues:

            Dr. Neff is taking us into a sensitive area.  The fact remains that the majority of American pollination biologists still refuse to identify the pollen grains carried by the insects they catch on flowers.  This leads to the premature conclusion that, "if I catch the insect in a flower, then that insect must be a pollinator or at least a potential/prospective pollinator of the flowers of that species."  Throughout the 20th century, and into the 21st, an entire "branch" of pollination ecology has been built on the notion that field notes and insect collections made in Illinois during the 1920's represent the Shining Path to pollinator identification/conservation.    

            It's a shame that relatively simple techniques of pollen identification instituted by the Australian Tarlton Rayment and the late Walter Macior are not used more often.  Yes, the grains of a broad number of North American plants are often very difficult to identify but the trick is to make a reference library of pollen slides from known plants before you harvest and identify pollen carried by insects.  It's still the best way as there are few pollen atlases published of any region.  Some grains are real signature grains and can't be mistaken for anything else provided you have the library to back you up.  This includes grains released as polyads or tetrads and those with prominently sculptured surfaces and apertures (pores and/or slits).  That's why you can easily identify both the fossil and living pollens of members of the WInteraceae.  Even look alike grains can betray their identity by their different sizes and the color and density of lipid droplets clinging to the pollen wall.  One of my graduate students found this a useful technique for separating pollen of the Rosaceae (Potentilla, Fragaria, Rosa etc.) found on the same bee at the same site.  The grains of North American Paeonia spp. are not very memorable either until you realize that their anthers release an unprecedented number of sterile collapsed grains (30-50%) and that's another signature in it's own way.  If you keep a library you may even be able to identify grains of two different species that belong to the same plant genus found on the same insect (see my past coauthored papers on Acacia and Persoonia). 

            One of the wash-the-pollen-off-the-insect, dry-the-residue and stain-the- residue techniques in the books mentioned by Dr. Neff is my technique.  That is, I modified pre-existing techniques learned in the lab of Bruce Knox at the U. of Melbourne from 1977-1985.  If I could do it all over again, though, I'd rewrite one aspect of those techniques.  I know now to never, never never wash pollen off an insect using ethanol.  You destroy the insect's cuticle and shorten the "useful life" of the pinned voucher specimen.  These days I wash pollen of insects using ethyl acetate.  Do this procedure in a fume hood, of course.

            Just remember that most pinned insect specimens came out of a communal killing jar.  The corpses bumped and clumped together so the presence of a few rose pollen grains on a bumblebee doesn't mean it every visited a rose in its life.  Something else in the jar may have foraged on that rose on that same day.  It's up to you to decide how many grains derived from a corpse amount to significant and sustained rates of foraging.  Wash your jars with soap and hot water and keep forceps and nets as clean as possible in-between usage.

            Sincerely, Peter I'm-still-washing-beetles Bernhardt         

            On Tue, Feb 9, 2010 at 10:13 AM, Jack Neff <jlnatctmi@...> wrote:
             

            All:  I would not be so negative about analyzing past dietary patterns from old pollen, at least for local faunas.  Extracting pollen from pinned specimens is easy (assuming they haven't been subjected to the current fad for specimen washing) and there are several methods available from the literature (Dafni et al, 2005; Kearns and Inouye, 1993).  Many pollens are quite distinctive and can be identified without any special preparation beyond staining, at least if one knows the local possibilities.  More nondescript pollen may require acetolysis, a nasty involved process.  SEM works exceedingly well but can be expensive if your institution does not have its own machine.  The key is having a good local reference collection for comparison purposes.  Identifying pollen from samples from across a broad area (the entire Great Plains) is much more problematic.   Identifying unknown pollens from an unknown flora can be extremely frustrating for the non-palynologist, and often isn't a snap even for the professional.

            best

            Jack


            John L. Neff
            Central Texas Melittological Institute
            7307 Running Rope
            Austin,TX 78731 USA
            512-345-7219



            From: "RestoreHabitat@..." <RestoreHabitat@...>
            To: beemonitoring@yahoogroups.com
            Sent: Mon, February 8, 2010 8:15:28 PM
            Subject: Re: [beemonitoring] Divining the floristic record of Bee Specimens

             

             
             
            To All
                       
                        The subject of bee phenology and Redbud is an excellent introduction to two questions, the answers for which I am seeking some assistance:
            • First question:  Would sampling of native bee specimens collected historically have the potential to reveal the species of pollen (and, therefore, the flora) from which they themselves were collecting when they were collected? I am not sufficiently familiar with methods of specimen collection to know if, historically, collection of species entailed netting and pinning but little else that would eliminate the pollen record that the specimen contained. Obviously, washed bees would not contain the information that I am seeking. My research to support restoration efforts has revealed substantial declines in nectar and pollen producing flora native to this region and to which our native pollinators are so well adapted.
            • That leads to the second question:  Has there been observed a measurable decline in the size of adult native bees (Bombus is a good example) during certain portions of their pollen and nectar gathering season over the past few decades? Recently, field observations have shown a remarkable decrease in the size of workers toward the end of the season. Does anyone have any information or guidance on data that would indicate whether this is typical, as observed historically; or, perhaps, a more modern development?
                     These data will assist in creating a comprehensive plan for restoration of heliophilic habitat that will support the greatest diversity of both native floral and fauna.
             
                            Randy Pheobus, President
                                Native Grassland Conservancy
                                    301-440-8915
                        


          • Doug Yanega
            ... Do you have either a simple summary, or links to online copies, of either or both of the techniques you mention? Perhaps more to the point, though, is the
            Message 5 of 7 , Feb 9, 2010
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              Peter Bernhardt wrote:

              >It's a shame that relatively simple techniques of pollen
              >identification instituted by the Australian Tarlton Rayment and the
              >late Walter Macior are not used more often. [snip]
              >
              >One of the wash-the-pollen-off-the-insect, dry-the-residue and
              >stain-the- residue techniques in the books mentioned by Dr. Neff is
              >my technique. That is, I modified pre-existing techniques learned
              >in the lab of Bruce Knox at the U. of Melbourne from 1977-1985. If
              >I could do it all over again, though, I'd rewrite one aspect of
              >those techniques. I know now to never, never never wash pollen off
              >an insect using ethanol. You destroy the insect's cuticle and
              >shorten the "useful life" of the pinned voucher specimen. These
              >days I wash pollen of insects using ethyl acetate. Do this
              >procedure in a fume hood, of course.

              Do you have either a simple summary, or links to online copies, of
              either or both of the techniques you mention? Perhaps more to the
              point, though, is the question as to why any washes need to be used
              at all?

              We have at least 80,000 old pinned bee specimens in our collection
              with scopal loads, and washing them individually, drying the residue
              individually, and staining the residue individually, is vastly more
              manpower-intensive than we could ever hope to manage, even if we had
              a source of outside funding. The number of samples even a full-time
              technician could process and ID per day is probably too low to be
              cost-effective, even if that technique itself is *materially* cheap.
              The wear and tear on the bee specimens and their labels is also VERY
              significant, and that alone would probably prevent us from even
              *attempting* such a project.

              So, for the kind of large-scale processing we would need, we would
              also need a highly streamlined procedure which requires minimal
              specimen handling. With that in mind, let me ask: would it be
              possible to place a very tiny droplet of some prepared medium on a
              slide, scrape pollen grains out of the scopa directly into this
              medium under a microscope, and drop a cover slip on it and be ready
              to go?

              If so, it would eliminate at least four or five time-consuming steps
              (the worst of them being having to strip all the labels off the pin
              in order to wash the specimen - and note that ethyl acetate can
              destroy pin heads! Morpho brand pins are especially vulnerable to
              this). This would still entail *some* wear and tear on the specimens
              - many hind legs would be snapped off - but this would be *orders of
              magnitude* less damage than the washing would cause, on specimens and
              labels 50+ years old.

              What do you think?

              Peace,
              --

              Doug Yanega Dept. of Entomology Entomology Research Museum
              Univ. of California, Riverside, CA 92521-0314 skype: dyanega
              phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
              http://cache.ucr.edu/~heraty/yanega.html
              "There are some enterprises in which a careful disorderliness
              is the true method" - Herman Melville, Moby Dick, Chap. 82
            • Jack Neff
              Doug et al. I take it you want to analyze what pollen bees are actively collecting (scopal pollen) rather than some crude record of what they may, or may not,
              Message 6 of 7 , Feb 9, 2010
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                Doug et al.

                I take it you want to analyze what pollen bees are actively collecting (scopal pollen) rather than some crude record of what they may, or may not, have visited (overall body pollen).  The latter is extremely important for  pollination studies but not so much for bee diet.  For the former, I heartily recommend the scrape-some-scopal pollen-onto-a-slide method (perhaps with some melted stained glycerin jelly).  Much quicker and less destructive than washes which unnecessarily combine pollen from different parts of the body.  If the first try doesn't yield anything readily identifiable, one can always go back to the scopa for another sample which may need further processing.

                best

                Jack


                John L. Neff
                Central Texas Melittological Institute
                7307 Running Rope
                Austin,TX 78731 USA
                512-345-7219



                From: Doug Yanega <dyanega@...>
                To: beemonitoring@yahoogroups.com
                Sent: Tue, February 9, 2010 12:32:38 PM
                Subject: Re: [beemonitoring] Divining the floristic record of Bee Specimens

                 

                Peter Bernhardt wrote:

                >It's a shame that relatively simple techniques of pollen
                >identification instituted by the Australian Tarlton Rayment and the
                >late Walter Macior are not used more often. [snip]
                >
                >One of the wash-the-pollen- off-the-insect, dry-the-residue and
                >stain-the- residue techniques in the books mentioned by Dr. Neff is
                >my technique. That is, I modified pre-existing techniques learned
                >in the lab of Bruce Knox at the U. of Melbourne from 1977-1985. If
                >I could do it all over again, though, I'd rewrite one aspect of
                >those techniques. I know now to never, never never wash pollen off
                >an insect using ethanol. You destroy the insect's cuticle and
                >shorten the "useful life" of the pinned voucher specimen. These
                >days I wash pollen of insects using ethyl acetate. Do this
                >procedure in a fume hood, of course.

                Do you have either a simple summary, or links to online copies, of
                either or both of the techniques you mention? Perhaps more to the
                point, though, is the question as to why any washes need to be used
                at all?

                We have at least 80,000 old pinned bee specimens in our collection
                with scopal loads, and washing them individually, drying the residue
                individually, and staining the residue individually, is vastly more
                manpower-intensive than we could ever hope to manage, even if we had
                a source of outside funding. The number of samples even a full-time
                technician could process and ID per day is probably too low to be
                cost-effective, even if that technique itself is *materially* cheap.
                The wear and tear on the bee specimens and their labels is also VERY
                significant, and that alone would probably prevent us from even
                *attempting* such a project.

                So, for the kind of large-scale processing we would need, we would
                also need a highly streamlined procedure which requires minimal
                specimen handling. With that in mind, let me ask: would it be
                possible to place a very tiny droplet of some prepared medium on a
                slide, scrape pollen grains out of the scopa directly into this
                medium under a microscope, and drop a cover slip on it and be ready
                to go?

                If so, it would eliminate at least four or five time-consuming steps
                (the worst of them being having to strip all the labels off the pin
                in order to wash the specimen - and note that ethyl acetate can
                destroy pin heads! Morpho brand pins are especially vulnerable to
                this). This would still entail *some* wear and tear on the specimens
                - many hind legs would be snapped off - but this would be *orders of
                magnitude* less damage than the washing would cause, on specimens and
                labels 50+ years old.

                What do you think?

                Peace,
                --

                Doug Yanega Dept. of Entomology Entomology Research Museum
                Univ. of California, Riverside, CA 92521-0314 skype: dyanega
                phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
                http://cache. ucr.edu/~ heraty/yanega. html
                "There are some enterprises in which a careful disorderliness
                is the true method" - Herman Melville, Moby Dick, Chap. 82


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