Loading ...
Sorry, an error occurred while loading the content.
 

Relative importance of pollinators

Expand Messages
  • Crystal Boyd
    Hi, everyone. I m hoping to tap your collective wisdom on this beautiful Friday morning. How do you speak about the relative importance of the 4 major
    Message 1 of 17 , Nov 15, 2013
      Hi, everyone. I'm hoping to tap your collective wisdom on this beautiful Friday morning.

      How do you speak about the "relative importance" of the 4 major pollinating groups (bees, butterflies and moths, flies, and beetles)? I can explain the importance of pollen foraging and floral constancy in bees, but people are asking for statistics to compare the groups.

      High-level comparisons can be misleading, for sure. I'll point out that even if beetles aren't the most efficient pollinators, they are (of course) critical to the plants they are pollinating.

      Thanks!
      -Crystal
    • Peter Bernhardt
      Dear Crystal: Before we do anything you have to give us an idea of parameters? Are we talking about the continental USA or globally? Different insects are
      Message 2 of 17 , Nov 15, 2013
        Dear Crystal:

        Before we do anything you have to give us an idea of parameters?  Are we talking about the continental USA or globally?  Different insects are important in different biomes globally.  For example, a recent paper notes that 80% of the beetles native to the canopies of Australian, tropical forests visit flowers (they do not munch on leaves).  Consequently, beetle-pollination might be more important in northern tropical forests of Australian then in southern temperate forests.  Likewise, hummingbird pollination is far more important in the western half of the United States (about 6 nesting species) but far less important east of the Mississippi River (only one nesting species).  We note that the majority of species of hummingbird-pollinated members of such families as the cacti, mints, snap dragons, phlox, honeysuckles, lilies etc. are western.  Their close relatives in the east tend to depend on bees and other insects.  Consequently, hummingbird pollination is probably far more important in South America (an estimated 230 native species) then in Canada and the continental U.S.

        Whatever the case, number-crunching will not be possible without a hard look at the literature from today to back to the 1870's (time in which Darwin's books really popularized the study of pollination in Europe, South Africa, America, Canada and Australia).  Unless Drs Inouye and Kevan have kept literature lists and statistics (they've published to big reviews on fly pollination, for example) all we can do is generalize.  

        Then there's the question of how you define importance.  Paeonia brownie is a threatened species important to conservation efforts in the U.S. and it is pollinated primarily by vespid and polistes wasps but there are relatively few studies of wasp pollination nationally or internationally.

        Peter


        On Fri, Nov 15, 2013 at 9:20 AM, Crystal Boyd <Crystal.Boyd@...> wrote:
         

        Hi, everyone. I'm hoping to tap your collective wisdom on this beautiful Friday morning.

        How do you speak about the "relative importance" of the 4 major pollinating groups (bees, butterflies and moths, flies, and beetles)? I can explain the importance of pollen foraging and floral constancy in bees, but people are asking for statistics to compare the groups.

        High-level comparisons can be misleading, for sure. I'll point out that even if beetles aren't the most efficient pollinators, they are (of course) critical to the plants they are pollinating.

        Thanks!
        -Crystal


      • Crystal Boyd
        Thanks, Peter. Parameters are another difficulty with these high-level comparisons. I m most interested in statistics for pollinator comparisons in Minnesota
        Message 3 of 17 , Nov 15, 2013
          Thanks, Peter. Parameters are another difficulty with these high-level comparisons. I'm most interested in statistics for pollinator comparisons in Minnesota (not available, I'm sure), the United States, or the globe. Really, though, I can use what's available. If there happen to be statistics for Australia, I could use those but explain the differences you highlight for different biomes.

          What about this?  This paper reports that 67% of flowering plants are pollinated by bees (but it's missing a reference for it). Then I'd just need stats about butterflies, moths, flies, beetles, thrips, etc... to split up the remaining 33%. Of course, this assumes that each plant species is pollinated by only one insect group.
          -Crystal


          On Fri, Nov 15, 2013 at 10:11 AM, Peter Bernhardt <bernhap2@...> wrote:
          Dear Crystal:

          Before we do anything you have to give us an idea of parameters?  Are we talking about the continental USA or globally?  Different insects are important in different biomes globally.  For example, a recent paper notes that 80% of the beetles native to the canopies of Australian, tropical forests visit flowers (they do not munch on leaves).  Consequently, beetle-pollination might be more important in northern tropical forests of Australian then in southern temperate forests.  Likewise, hummingbird pollination is far more important in the western half of the United States (about 6 nesting species) but far less important east of the Mississippi River (only one nesting species).  We note that the majority of species of hummingbird-pollinated members of such families as the cacti, mints, snap dragons, phlox, honeysuckles, lilies etc. are western.  Their close relatives in the east tend to depend on bees and other insects.  Consequently, hummingbird pollination is probably far more important in South America (an estimated 230 native species) then in Canada and the continental U.S.

          Whatever the case, number-crunching will not be possible without a hard look at the literature from today to back to the 1870's (time in which Darwin's books really popularized the study of pollination in Europe, South Africa, America, Canada and Australia).  Unless Drs Inouye and Kevan have kept literature lists and statistics (they've published to big reviews on fly pollination, for example) all we can do is generalize.  

          Then there's the question of how you define importance.  Paeonia brownie is a threatened species important to conservation efforts in the U.S. and it is pollinated primarily by vespid and polistes wasps but there are relatively few studies of wasp pollination nationally or internationally.

          Peter


          On Fri, Nov 15, 2013 at 9:20 AM, Crystal Boyd <Crystal.Boyd@...> wrote:
           

          Hi, everyone. I'm hoping to tap your collective wisdom on this beautiful Friday morning.

          How do you speak about the "relative importance" of the 4 major pollinating groups (bees, butterflies and moths, flies, and beetles)? I can explain the importance of pollen foraging and floral constancy in bees, but people are asking for statistics to compare the groups.

          High-level comparisons can be misleading, for sure. I'll point out that even if beetles aren't the most efficient pollinators, they are (of course) critical to the plants they are pollinating.

          Thanks!
          -Crystal



        • Cane, Jim
          Folks- since only some small fraction of plant species have been studied as regards even their basic breeding system, let alone quantifying floral visitation
          Message 4 of 17 , Nov 15, 2013

            Folks- since only some small fraction of plant species have been studied as regards even their basic breeding system, let alone quantifying floral visitation intensities and efficacies of candidate pollinators, I would be very suspect of any sweeping generality about the “importance” of pollinator groups.  As an example, the largest genus of flowering plants, Astragalus (3270 named species), has classic pea-shaped flowers, so one might expect that it needs bees for seed set.  It is true that bees are prevalent where people have looked, but for only 29 or 3279 species do we know anything about pollination needs, and among those 29, it runs that gamut from cleistogamy to obligate outcrosser.  So how does anyone justify extrapolating to the other 3241 species in the genus?  If you simply change your generalization from “most” to “many” you can be safe, but an actual number will be largely drawn out of thin air, I believe.

             

            Yours,

             

            Jim

             

            ===============================

            James H. Cane

            USDA-ARS Pollinating Insect Research Unit

            Utah State University, Logan, UT 84322 USA

            tel: 435-797-3879   FAX: 435-797-0461

            email: Jim.Cane@... 

            web page: www.ars.usda.gov/npa/beelab

            publications: http://digitalcommons.usu.edu/piru/

            Gardening for Bees: http://extension.usu.edu/files/publications/factsheet/plants-pollinators09.pdf

             





            This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately.
          • Peter Bernhardt
            Jim is right. This is the sort of thing you can give only as an estimate with a WARNING that research lags and lags. Plenty of pollination books (texts and
            Message 5 of 17 , Nov 15, 2013
              Jim is right.  This is the sort of thing you can give only as an estimate with a WARNING that research lags and lags.  Plenty of pollination books (texts and references) will offer these estimates but what are the really based on?

              Peter


              On Fri, Nov 15, 2013 at 10:51 AM, Cane, Jim <Jim.Cane@...> wrote:

              Folks- since only some small fraction of plant species have been studied as regards even their basic breeding system, let alone quantifying floral visitation intensities and efficacies of candidate pollinators, I would be very suspect of any sweeping generality about the “importance” of pollinator groups.  As an example, the largest genus of flowering plants, Astragalus (3270 named species), has classic pea-shaped flowers, so one might expect that it needs bees for seed set.  It is true that bees are prevalent where people have looked, but for only 29 or 3279 species do we know anything about pollination needs, and among those 29, it runs that gamut from cleistogamy to obligate outcrosser.  So how does anyone justify extrapolating to the other 3241 species in the genus?  If you simply change your generalization from “most” to “many” you can be safe, but an actual number will be largely drawn out of thin air, I believe.

               

              Yours,

               

              Jim

               

              ===============================

              James H. Cane

              USDA-ARS Pollinating Insect Research Unit

              Utah State University, Logan, UT 84322 USA

              tel: 435-797-3879   FAX: 435-797-0461

              email: Jim.Cane@... 

              web page: www.ars.usda.gov/npa/beelab

              publications: http://digitalcommons.usu.edu/piru/

              Gardening for Bees: http://extension.usu.edu/files/publications/factsheet/plants-pollinators09.pdf

               





              This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately.

            • pollinator2001
              How are you defining pollination? In a botanical sense, I guess you d say a plant was pollinated if it produced a few seeds. But in a agricultural system,
              Message 6 of 17 , Nov 15, 2013

                How are you defining pollination?  In a botanical sense, I guess you'd say a plant was pollinated if it produced a few seeds.  But in a agricultural system, that would be an inadequate definition for multi-seeded crops like apples, strawberries, watermelon, kiwi fruit, tomatoes, or squash. You would want the delivery of sufficient quantities of pollen grains to have 90% or more of the ovules fertilized. For watermelons, that would mean about 1000 grains of viable pollen, evenly distributed across the lobes of the stigma. Only in this manner can a quality fruit be produced. 


                Dave Green

                Retired pollination contractor

                Coastal SC



                ---In beemonitoring@yahoogroups.com, <Crystal.Boyd@...> wrote:

                Hi, everyone. I'm hoping to tap your collective wisdom on this beautiful Friday morning.

                How do you speak about the "relative importance" of the 4 major pollinating groups (bees, butterflies and moths, flies, and beetles)? I can explain the importance of pollen foraging and floral constancy in bees, but people are asking for statistics to compare the groups.

                High-level comparisons can be misleading, for sure. I'll point out that even if beetles aren't the most efficient pollinators, they are (of course) critical to the plants they are pollinating.

                Thanks!
                -Crystal
              • Mitchell,Randall J
                I agree that answering Crystal s question about relative importance of pollinator groups properly will require much more context and precision. But I think
                Message 7 of 17 , Nov 16, 2013
                  I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.

                  For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)

                  When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                  Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.

                  I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                  Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                  Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.

                  For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.

                  Randy Mitchell
                • Colin Phifer
                  What a good discussion! The 3 of 4 bits is often quoted but I wanted to add another dimension to the discussion. Many of the most pollinator dependent food
                  Message 8 of 17 , Nov 16, 2013
                    What a good discussion! The "3 of 4 bits" is often quoted but I wanted to add another dimension to the discussion. Many of the most pollinator dependent food crops are also the main sources for certain vital nutrients needed for human health. I'm pasted in the abstract and linked to the citation. Cheers, cp

                    Abstract:

                    The contribution of nutrients from animal pollinated world crops has not previously been evaluated as a biophysical measure for the value of pollination services. This study evaluates the nutritional composition of animal-pollinated world crops. We calculated pollinator dependent and independent proportions of different nutrients of world crops, employing FAO data for crop production, USDA data for nutritional composition, and pollinator dependency data according to Klein et al. (2007). Crop plants that depend fully or partially on animal pollinators contain more than 90% of vitamin C, the whole quantity of Lycopene and almost the full quantity of the antioxidants β-cryptoxanthin and β-tocopherol, the majority of the lipid, vitamin A and related carotenoids, calcium and fluoride, and a large portion of folic acid. Ongoing pollinator decline may thus exacerbate current difficulties of providing a nutritionally adequate diet for the global human population.

                    Citation:
                    Elisabeth J. Eilers, Claire Kremen, Sarah Smith Greenleaf, Andrea K. Garber, and Alexandra-Maria Klein. 2011.

                    • • • • • • • • • •
                    Colin Phifer, PhD Student
                    School of Forest Resources & Environmental Science
                    Michigan Tech University
                    1400 Townsend Drive
                    Houghton, MI 49931-1295
                    Phone: (808)-315-2830
                    Email: ccphifer@...


                    On Nov 16, 2013, at 5:31 AM, "Mitchell,Randall J" <rjm2@...> wrote:

                     

                    I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.

                    For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)

                    When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                    Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.

                    I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                    Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                    Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.

                    For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.

                    Randy Mitchell


                  • Jack Neff
                    The discussion seems to have veered far from the original question about the importance of different pollinator groups which of course varies with the
                    Message 9 of 17 , Nov 16, 2013
                      The discussion seems to have veered far from the original question about the "importance" of different pollinator groups which of course varies with the habitat and which particular plants one is talking about, plus what definition of importance one is using.  
                      I would be careful about casually throwing about the 70% of our most important food crops or 2 in every three bites are dependent on pollinators.  I believe the actual number is that 70% are to some degree, dependent on pollinators and the USDA says that 1 in every three bites is at least partially dependent on animal pollinators.  World crop estimates are that animal pollination adds about 10% to the monetary value of all food crops.  Not quite the same as the more exuberant numbers often tossed around.  Obviously pollinators are extremely important to some crops but good intentions does not justify exaggeration.

                      best

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


                      On Saturday, November 16, 2013 10:25 AM, Colin Phifer <ccphifer@...> wrote:
                       
                      What a good discussion! The "3 of 4 bits" is often quoted but I wanted to add another dimension to the discussion. Many of the most pollinator dependent food crops are also the main sources for certain vital nutrients needed for human health. I'm pasted in the abstract and linked to the citation. Cheers, cp

                      Abstract:

                      The contribution of nutrients from animal pollinated world crops has not previously been evaluated as a biophysical measure for the value of pollination services. This study evaluates the nutritional composition of animal-pollinated world crops. We calculated pollinator dependent and independent proportions of different nutrients of world crops, employing FAO data for crop production, USDA data for nutritional composition, and pollinator dependency data according to Klein et al. (2007). Crop plants that depend fully or partially on animal pollinators contain more than 90% of vitamin C, the whole quantity of Lycopene and almost the full quantity of the antioxidants β-cryptoxanthin and β-tocopherol, the majority of the lipid, vitamin A and related carotenoids, calcium and fluoride, and a large portion of folic acid. Ongoing pollinator decline may thus exacerbate current difficulties of providing a nutritionally adequate diet for the global human population.

                      Citation:
                      Elisabeth J. Eilers, Claire Kremen, Sarah Smith Greenleaf, Andrea K. Garber, and Alexandra-Maria Klein. 2011.

                      • • • • • • • • • •
                      Colin Phifer, PhD Student
                      School of Forest Resources & Environmental Science
                      Michigan Tech University
                      1400 Townsend Drive
                      Houghton, MI 49931-1295
                      Phone: (808)-315-2830
                      Email: ccphifer@...


                      On Nov 16, 2013, at 5:31 AM, "Mitchell,Randall J" <rjm2@...> wrote:

                       
                      I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.

                      For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)

                      When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                      Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.

                      I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                      Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                      Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.

                      For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.

                      Randy Mitchell




                    • Cane, Jim
                      Folks- you will also notice that the one in three bites quote implies that a third of what you eat results from insect pollination. I believe that the
                      Message 10 of 17 , Nov 17, 2013

                        Folks- you will also notice that the “one in three bites” quote implies that a third of what you eat results from insect pollination.  I believe that the original calculation is that a third of the crop SPECIES that we eat are bee pollinated. Thus, wheat is counted with the same weight as, for example, eggplant.  In the original formulation too (whose lineage I believe traces back to MacGregor in his “Insect Pollination of Cultivated Crop Plants), alfalfa featured prominently as feed for dairy (and beef?…I forget) and all of the resultant milk, cheese, ice cream and butter that results.  In reality, alfalfa hay is only important in some regions, particularly drier areas where alternative forages and silage crops won’t grow for lack of enough water (in the U.S., a vivid example is all of the massive dairies along the Rio Grande River north of El Paso).  With alfalfa, no bees, no seed, so it gets a high score.  For some of those big crops, as Jack notes, the contribution of bee pollination is small or restricted to select cultivars (many citrus come to mind, or cotton).  Those are well-summarized in John Free’s big crop pollination book.

                         

                        I say all of this not because I undervalue bees as pollinators.  I like eating much of what bees pollinate, and without them, our diets would be more boring, less nutritious and the businesses of many farmers and processors would be devastated in the US and around the world.  However, I have been approached on multiple occasions by non-scientists (I remember in particular a cameraman on a film crew) who, reflecting on their own diets, confided that they thought that the “one in 3 bites” could not be true and wanted confirmation.  You need only tot up what you eat tomorrow to realize it for yourself.  With every person who correctly questions the assertion, and feels a bit misled, we advocates of bees lose a little credibility.

                         

                        I state all of this directly, but please, if I have my facts wrong or am missing the right interpretation, do speak up!  I am always wanting  to tailor or change my perspective with new and persuasive insights.

                         

                        Jim

                         

                        ===============================

                        James H. Cane

                        USDA-ARS Pollinating Insect Research Unit

                        Utah State University, Logan, UT 84322 USA





                        This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately.
                      • John Mola
                        I am fairly certain it is 1/3 of agricultural production by *volume* is from bee pollinated crops. Yet, within that, each of those crops is more or less pollen
                        Message 11 of 17 , Nov 17, 2013
                          I am fairly certain it is 1/3 of agricultural production by volume is from bee pollinated crops. Yet, within that, each of those crops is more or less pollen limited. So in the end, you actually get far less than 1/3 by volume. Usually, when discussing this, I highlight what Jim said above: the exciting and nutritious foods are often bee pollinated!

                          In regards to the original question, I would contend you at least have to add birds to the groups (and maybe others). Unless we are sticking to insect pollinators only, I'm fairly certain birds play a large role in some areas.

                          John


                          On Sun, Nov 17, 2013 at 11:29 AM, Cane, Jim <Jim.Cane@...> wrote:
                           

                          Folks- you will also notice that the “one in three bites” quote implies that a third of what you eat results from insect pollination.  I believe that the original calculation is that a third of the crop SPECIES that we eat are bee pollinated. Thus, wheat is counted with the same weight as, for example, eggplant.  In the original formulation too (whose lineage I believe traces back to MacGregor in his “Insect Pollination of Cultivated Crop Plants), alfalfa featured prominently as feed for dairy (and beef?…I forget) and all of the resultant milk, cheese, ice cream and butter that results.  In reality, alfalfa hay is only important in some regions, particularly drier areas where alternative forages and silage crops won’t grow for lack of enough water (in the U.S., a vivid example is all of the massive dairies along the Rio Grande River north of El Paso).  With alfalfa, no bees, no seed, so it gets a high score.  For some of those big crops, as Jack notes, the contribution of bee pollination is small or restricted to select cultivars (many citrus come to mind, or cotton).  Those are well-summarized in John Free’s big crop pollination book.

                           

                          I say all of this not because I undervalue bees as pollinators.  I like eating much of what bees pollinate, and without them, our diets would be more boring, less nutritious and the businesses of many farmers and processors would be devastated in the US and around the world.  However, I have been approached on multiple occasions by non-scientists (I remember in particular a cameraman on a film crew) who, reflecting on their own diets, confided that they thought that the “one in 3 bites” could not be true and wanted confirmation.  You need only tot up what you eat tomorrow to realize it for yourself.  With every person who correctly questions the assertion, and feels a bit misled, we advocates of bees lose a little credibility.

                           

                          I state all of this directly, but please, if I have my facts wrong or am missing the right interpretation, do speak up!  I am always wanting  to tailor or change my perspective with new and persuasive insights.

                           

                          Jim

                           

                          ===============================

                          James H. Cane

                          USDA-ARS Pollinating Insect Research Unit

                          Utah State University, Logan, UT 84322 USA





                          This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately.




                          --
                          John Mola
                          JohnMMola@...




                        • Peter Bernhardt
                          Dear David: Botanists define the word, pollination, as the deposition of pollen grains on a pollen receptive/processing surface. In gymnosperms the surface
                          Message 12 of 17 , Nov 18, 2013
                          Dear David:

                          Botanists define the word, pollination, as the deposition of pollen grains on a pollen receptive/processing surface.   In gymnosperms the surface is usually a droplet on the micropyle.  In angiosperms, of course, the receptive stigma provides the surface.  Modern botanists don't define pollination in terms of seed set as seeds are produced by fertilization (usually accompanied by fructification) not pollination.  Yes, I'm aware that scientists once used fertilization and pollination interchangeably (Darwin did it) but that went out of fashion almost a century ago.  You EAT with your mouth.  You DIGEST what you eat with your innards...right?      

                          Since a receptive stigma is pollinated if only one pollen grain lands on it the actual conversion rate of ovules into seeds is often just as variable in natural as in agricultural systems.   Trust me (and see attached), some wild plants are pollen-limited because they are pollinator-limited.  Bees pollinated three sun orchids in our study but, very often, bees failed to show up.  Doe this mean that bees are not the most important pollinators of three species of sun orchid?   For that matter, populations of wild strawberries (Fragaria virginiana) in eastern North America and Andean South America (F. chiloensis) exist as male and female plants (dioecious) just as our populations are made of men and women.  Small bees are the native pollinators of female strawberries but, as male flowers lack functional pistils they aren't pollinated at all... right?  Does this mean that small native bees are not the most important pollinators of wild, strawberries of the Western Hemisphere because they only pollinate half the population, at best?   

                          Peter Bernhardt


                          On Fri, Nov 15, 2013 at 4:55 PM, <Pollinator@...> wrote:
                           

                          How are you defining pollination?  In a botanical sense, I guess you'd say a plant was pollinated if it produced a few seeds.  But in a agricultural system, that would be an inadequate definition for multi-seeded crops like apples, strawberries, watermelon, kiwi fruit, tomatoes, or squash. You would want the delivery of sufficient quantities of pollen grains to have 90% or more of the ovules fertilized. For watermelons, that would mean about 1000 grains of viable pollen, evenly distributed across the lobes of the stigma. Only in this manner can a quality fruit be produced. 


                          Dave Green

                          Retired pollination contractor

                          Coastal SC



                          ---In beemonitoring@yahoogroups.com, <Crystal.Boyd@...> wrote:

                          Hi, everyone. I'm hoping to tap your collective wisdom on this beautiful Friday morning.

                          How do you speak about the "relative importance" of the 4 major pollinating groups (bees, butterflies and moths, flies, and beetles)? I can explain the importance of pollen foraging and floral constancy in bees, but people are asking for statistics to compare the groups.

                          High-level comparisons can be misleading, for sure. I'll point out that even if beetles aren't the most efficient pollinators, they are (of course) critical to the plants they are pollinating.

                          Thanks!
                          -Crystal


                        • Peter Bernhardt
                          Dear Randy: As the three out of four bites statement represents an estimate by Nabhan and Buchmann why not ask them how they arrived at it? What data did
                          Message 13 of 17 , Nov 18, 2013
                            Dear Randy:

                            As the "three out of four bites" statement represents an estimate by Nabhan and Buchmann why not ask them how they arrived at it?  What data did they use?  Surely, they consulted Free's "Insect Pollination of Crops" (1970).  Does the information in that book remain valid today?  Self-pollinating breeds of soybeans may have replaced bee-pollinated breeds.  On the other hand, Free wrote the book before Armstrong did all that work on the pollination of domesticated and wild nutmegs.   

                            Meanwhile, there are plenty of literature reviews on pollination by specific animal groups.  Ask Dr Inouye for a copy of his most recent, multi-authored review of fly-pollination.  Why not find and read them before estimating anything at all?  Bioinformatics looks impressive but won't solve much in this case as we don't know the pollinators of most of the angiosperm species on this planet and, NO, I won't estimate the number of unstudied angiosperm species.  Perhaps readers need to be impressed by our sheer ignorance and remind them that only a few people have attempted scientific analyses of the ecological service we call pollination since 1793.

                            Peter Bernhardt


                            On Sat, Nov 16, 2013 at 4:31 AM, Mitchell,Randall J <rjm2@...> wrote:
                             

                            I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.

                            For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)

                            When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                            Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.

                            I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                            Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                            Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.

                            For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.

                            Randy Mitchell


                          • Crystal Boyd
                            Thanks, everyone, for a great discussion. We ve really highlighted the difficulties with broad statistics, and I ve wondered about the 1 in 3 bites statement
                            Message 14 of 17 , Nov 18, 2013
                              Thanks, everyone, for a great discussion. We've really highlighted the difficulties with broad statistics, and I've wondered about the "1 in 3 bites" statement myself. There are some great comments about it here:
                              http://www.honeybeesuite.com/bees-pollinate-one-third-of-what-do-we-really-know/

                              The fact that these statistics are being repeated so frequently, though, shows that the media and the public want clear, concise statements about troubling issues.
                              -Crystal


                              On Mon, Nov 18, 2013 at 8:59 AM, Peter Bernhardt <bernhap2@...> wrote:
                               

                              Dear Randy:

                              As the "three out of four bites" statement represents an estimate by Nabhan and Buchmann why not ask them how they arrived at it?  What data did they use?  Surely, they consulted Free's "Insect Pollination of Crops" (1970).  Does the information in that book remain valid today?  Self-pollinating breeds of soybeans may have replaced bee-pollinated breeds.  On the other hand, Free wrote the book before Armstrong did all that work on the pollination of domesticated and wild nutmegs.   

                              Meanwhile, there are plenty of literature reviews on pollination by specific animal groups.  Ask Dr Inouye for a copy of his most recent, multi-authored review of fly-pollination.  Why not find and read them before estimating anything at all?  Bioinformatics looks impressive but won't solve much in this case as we don't know the pollinators of most of the angiosperm species on this planet and, NO, I won't estimate the number of unstudied angiosperm species.  Perhaps readers need to be impressed by our sheer ignorance and remind them that only a few people have attempted scientific analyses of the ecological service we call pollination since 1793.

                              Peter Bernhardt


                              On Sat, Nov 16, 2013 at 4:31 AM, Mitchell,Randall J <rjm2@...> wrote:
                               

                              I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.

                              For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)

                              When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                              Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.

                              I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                              Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                              Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.

                              For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.

                              Randy Mitchell



                            • Emily May
                              Hi all, A clearer source for the 1 in 3 bites statement may derive from Klein et al (2007)
                              Message 15 of 17 , Nov 18, 2013
                                Hi all,

                                A clearer source for the "1 in 3 bites" statement may derive from Klein et al (2007). The review found that 39 of 57 leading single crops (accounting for 35% of global food production by volume, according to the FAO) are dependent to some degree on animal pollination, but the amount of production directly attributable to animals is lower than this value (because the degree of dependence varies by crop). The supplemental information reviews what is known about the pollination biology and pollinators/visitors to each of the leading crops.

                                -Emily

                                Citation:
                                Klein, A.M., Vassière, B.E., Cane, J.H., Steffan-Dewenter, I., Cunningham, S.A., Kremen, C., and Tscharntke, T. (2007). Importance of pollinators in changing landscapes for world crops. Proceedings of the Royal Society B: Biological Sciences, 274: 303-313.

                                Abstract:
                                The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.


                                -- 
                                Emily May
                                Department of Entomology
                                Michigan State University
                                202 Center for Integrated Plant Systems
                                East Lansing, MI 48824
                                Lab: 517-432-9554


                                On Mon, Nov 18, 2013 at 9:59 AM, Peter Bernhardt <bernhap2@...> wrote:
                                >
                                >  
                                >
                                > Dear Randy:
                                >
                                > As the "three out of four bites" statement represents an estimate by Nabhan and Buchmann why not ask them how they arrived at it?  What data did they use?  Surely, they consulted Free's "Insect Pollination of Crops" (1970).  Does the information in that book remain valid today?  Self-pollinating breeds of soybeans may have replaced bee-pollinated breeds.  On the other hand, Free wrote the book before Armstrong did all that work on the pollination of domesticated and wild nutmegs.  
                                >
                                > Meanwhile, there are plenty of literature reviews on pollination by specific animal groups.  Ask Dr Inouye for a copy of his most recent, multi-authored review of fly-pollination.  Why not find and read them before estimating anything at all?  Bioinformatics looks impressive but won't solve much in this case as we don't know the pollinators of most of the angiosperm species on this planet and, NO, I won't estimate the number of unstudied angiosperm species.  Perhaps readers need to be impressed by our sheer ignorance and remind them that only a few people have attempted scientific analyses of the ecological service we call pollination since 1793.
                                >
                                > Peter Bernhardt
                                >
                                >
                                > On Sat, Nov 16, 2013 at 4:31 AM, Mitchell,Randall J <rjm2@...> wrote:
                                >>
                                >>  
                                >>
                                >> I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.
                                >>
                                >> For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)
                                >>
                                >> When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                                >> Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.
                                >>
                                >> I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                                >> Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                                >> Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.
                                >>
                                >> For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.
                                >>
                                >> Randy Mitchell
                                >>
                                >
                                >





                              • Peter Bernhardt
                                Dear Emily: Thank you for the clarification. Let s consider one more factor. Many crops are consumed prior to the act of pollination. For example, every
                                Message 16 of 17 , Nov 18, 2013
                                  Dear Emily:

                                  Thank you for the clarification.  Let's consider one more factor.  Many crops are consumed prior to the act of pollination.  For example, every supermarket lettuce dies a virgin (see Bernhardt, 1993, Chapter 3).   However, insects remain essential to the production of many of these crops as you can't grow lettuce without starting with a seed and that seed is the ultimate result of employing animals to pollinate the seed's parent plants.

                                  I'm reminded of several years of work on wild plants in Oregon.  Much of Oregon's economic success in agriculture does not come from exporting edible crops.  It comes from exporting viable seeds that are then as grown as edible crops outside Oregon.  Some of these were wind-pollinated, admittedly, and I passed numerous farms harvesting grass seed (for sacks of lawn seeds) and sugar beets (seed for farms in other parts of the country).  The packages of carrot, celery, turnip, lettuce, cabbage, cauliflower etc. purchased by farmers and home gardeners must come ultimately from specialized farms where the seed, not the edible product, is produced.  They can't be produced unless certain animals are encouraged to forage on rewards offered by inedible flowers.  Is this also what Nabhan and Buchmann alluded to when they gave us the "bites" truism?

                                  Peter


                                  On Mon, Nov 18, 2013 at 9:48 AM, Emily May <mayemil1@...> wrote:
                                  Hi all,

                                  A clearer source for the "1 in 3 bites" statement may derive from Klein et al (2007). The review found that 39 of 57 leading single crops (accounting for 35% of global food production by volume, according to the FAO) are dependent to some degree on animal pollination, but the amount of production directly attributable to animals is lower than this value (because the degree of dependence varies by crop). The supplemental information reviews what is known about the pollination biology and pollinators/visitors to each of the leading crops.

                                  -Emily

                                  Citation:
                                  Klein, A.M., Vassière, B.E., Cane, J.H., Steffan-Dewenter, I., Cunningham, S.A., Kremen, C., and Tscharntke, T. (2007). Importance of pollinators in changing landscapes for world crops. Proceedings of the Royal Society B: Biological Sciences, 274: 303-313.

                                  Abstract:
                                  The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.


                                  -- 
                                  Emily May
                                  Department of Entomology
                                  Michigan State University
                                  202 Center for Integrated Plant Systems
                                  East Lansing, MI 48824
                                  Lab: 517-432-9554



                                  On Mon, Nov 18, 2013 at 9:59 AM, Peter Bernhardt <bernhap2@...> wrote:
                                  >
                                  >  
                                  >
                                  > Dear Randy:
                                  >
                                  > As the "three out of four bites" statement represents an estimate by Nabhan and Buchmann why not ask them how they arrived at it?  What data did they use?  Surely, they consulted Free's "Insect Pollination of Crops" (1970).  Does the information in that book remain valid today?  Self-pollinating breeds of soybeans may have replaced bee-pollinated breeds.  On the other hand, Free wrote the book before Armstrong did all that work on the pollination of domesticated and wild nutmegs.  
                                  >
                                  > Meanwhile, there are plenty of literature reviews on pollination by specific animal groups.  Ask Dr Inouye for a copy of his most recent, multi-authored review of fly-pollination.  Why not find and read them before estimating anything at all?  Bioinformatics looks impressive but won't solve much in this case as we don't know the pollinators of most of the angiosperm species on this planet and, NO, I won't estimate the number of unstudied angiosperm species.  Perhaps readers need to be impressed by our sheer ignorance and remind them that only a few people have attempted scientific analyses of the ecological service we call pollination since 1793.
                                  >
                                  > Peter Bernhardt
                                  >
                                  >
                                  > On Sat, Nov 16, 2013 at 4:31 AM, Mitchell,Randall J <rjm2@...> wrote:
                                  >>
                                  >>  
                                  >>
                                  >> I agree that answering Crystal's question about relative importance of pollinator groups properly will require much more context and precision. But I think that misses the real question - what can we tell an interested and concerned public audience about the importance of the big 4 pollinator groups in general, so they have some tools to think about a topic that is new to them.
                                  >>
                                  >> For example, the '3 out of 4 bites depend on a pollinator' statement is very commonly used, and although it obviously depends on a number of general assumptions, it helps to put the issue into a context the public can understand. (the best estimate I know of is a bit higher - 87%: Ollerton, J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by animals?" Oikos 120: 321-326.)
                                  >>
                                  >> When talking about this topic in public a forum I often point out that for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and S. L. Buchmann (1997). Services provided by pollinators. Nature's services: societal dependence on natural ecosystems. G. C. Daily. Washington, DC, Island Press: 133-150.).
                                  >> Although this statement doesn't directly apply to wild plants, it gives a flavor of relative importance in one context, and lets the conversation move on to pollinators and the challenges they face in general.
                                  >>
                                  >> I think that providing a more technically correct answer than this slightly vague approach is not yet possible.
                                  >> Using pollination syndromes to infer the most effective pollinator has many difficulties, though it may provide another broad-brush starting point.
                                  >> Directly measuring the dependence on each potential pollinator of each plant is an enormous and difficult task (as pointed out by others in this thread), and doing so for all the species in a community (or larger area, such as a state) would be orders of magnitude harder. Meta-analysis of studies from different communities might eventually be useful - I don't know of any to date.
                                  >>
                                  >> For now, I think case studies and anecdotes will probably have to do, but might actually be enough for Crystal's audience.
                                  >>
                                  >> Randy Mitchell
                                  >>
                                  >
                                  >






                                • Emily May
                                  Hi Peter, Good point. The 35% of global food production by volume figure from Klein et al. (2007) includes the types of crops you ve indicated - sub-categories
                                  Message 17 of 17 , Nov 18, 2013
                                    Hi Peter,

                                    Good point. The 35% of global food production by volume figure from
                                    Klein et al. (2007) includes the types of crops you've indicated -
                                    sub-categories of pollinator-dependent crops include "production
                                    increase with pollinators for plant parts that we consume (fruits
                                    and/or seeds: 26 crops with 12 ,108 Mt=55%); increase in seed
                                    production with pollinators to produce the vegetative parts that we
                                    consume (six crops with 2,108 Mt=9%); and increase in seed production
                                    with animals for breeding alone, as the plants reproduce vegetatively
                                    and we consume the vegetative parts (seven crops with 8108 Mt=36%)."

                                    Best,
                                    Emily

                                    On Mon, Nov 18, 2013 at 11:15 AM, Peter Bernhardt <bernhap2@...> wrote:
                                    >
                                    >
                                    > Dear Emily:
                                    >
                                    > Thank you for the clarification. Let's consider one more factor. Many
                                    > crops are consumed prior to the act of pollination. For example, every
                                    > supermarket lettuce dies a virgin (see Bernhardt, 1993, Chapter 3).
                                    > However, insects remain essential to the production of many of these crops
                                    > as you can't grow lettuce without starting with a seed and that seed is the
                                    > ultimate result of employing animals to pollinate the seed's parent plants.
                                    >
                                    > I'm reminded of several years of work on wild plants in Oregon. Much of
                                    > Oregon's economic success in agriculture does not come from exporting edible
                                    > crops. It comes from exporting viable seeds that are then as grown as
                                    > edible crops outside Oregon. Some of these were wind-pollinated,
                                    > admittedly, and I passed numerous farms harvesting grass seed (for sacks of
                                    > lawn seeds) and sugar beets (seed for farms in other parts of the country).
                                    > The packages of carrot, celery, turnip, lettuce, cabbage, cauliflower etc.
                                    > purchased by farmers and home gardeners must come ultimately from
                                    > specialized farms where the seed, not the edible product, is produced. They
                                    > can't be produced unless certain animals are encouraged to forage on rewards
                                    > offered by inedible flowers. Is this also what Nabhan and Buchmann alluded
                                    > to when they gave us the "bites" truism?
                                    >
                                    > Peter
                                    >
                                    >
                                    > On Mon, Nov 18, 2013 at 9:48 AM, Emily May <mayemil1@...> wrote:
                                    >>
                                    >> Hi all,
                                    >>
                                    >> A clearer source for the "1 in 3 bites" statement may derive from Klein et
                                    >> al (2007). The review found that 39 of 57 leading single crops (accounting
                                    >> for 35% of global food production by volume, according to the FAO) are
                                    >> dependent to some degree on animal pollination, but the amount of production
                                    >> directly attributable to animals is lower than this value (because the
                                    >> degree of dependence varies by crop). The supplemental information reviews
                                    >> what is known about the pollination biology and pollinators/visitors to each
                                    >> of the leading crops.
                                    >>
                                    >> -Emily
                                    >>
                                    >> Citation:
                                    >> Klein, A.M., Vassière, B.E., Cane, J.H., Steffan-Dewenter, I., Cunningham,
                                    >> S.A., Kremen, C., and Tscharntke, T. (2007). Importance of pollinators in
                                    >> changing landscapes for world crops. Proceedings of the Royal Society B:
                                    >> Biological Sciences, 274: 303-313.
                                    >>
                                    >> Abstract:
                                    >> The extent of our reliance on animal pollination for world crop production
                                    >> for human food has not previously been evaluated and the previous estimates
                                    >> for countries or continents have seldom used primary data. In this review,
                                    >> we expand the previous estimates using novel primary data from 200 countries
                                    >> and found that fruit, vegetable or seed production from 87 of the leading
                                    >> global food crops is dependent upon animal pollination, while 28 crops do
                                    >> not rely upon animal pollination. However, global production volumes give a
                                    >> contrasting perspective, since 60% of global production comes from crops
                                    >> that do not depend on animal pollination, 35% from crops that depend on
                                    >> pollinators, and 5% are unevaluated. Using all crops traded on the world
                                    >> market and setting aside crops that are solely passively self-pollinated,
                                    >> wind-pollinated or parthenocarpic, we then evaluated the level of dependence
                                    >> on animal-mediated pollination for crops that are directly consumed by
                                    >> humans. We found that pollinators are essential for 13 crops, production is
                                    >> highly pollinator dependent for 30, moderately for 27, slightly for 21,
                                    >> unimportant for 7, and is of unknown significance for the remaining 9. We
                                    >> further evaluated whether local and landscape-wide management for natural
                                    >> pollination services could help to sustain crop diversity and production.
                                    >> Case studies for nine crops on four continents revealed that agricultural
                                    >> intensification jeopardizes wild bee communities and their stabilizing
                                    >> effect on pollination services at the landscape scale.
                                    >>
                                    >>
                                    >> --
                                    >> Emily May
                                    >> Department of Entomology
                                    >> Michigan State University
                                    >> 202 Center for Integrated Plant Systems
                                    >> East Lansing, MI 48824
                                    >> Lab: 517-432-9554
                                    >>
                                    >>
                                    >>
                                    >> On Mon, Nov 18, 2013 at 9:59 AM, Peter Bernhardt <bernhap2@...> wrote:
                                    >> >
                                    >> >
                                    >> >
                                    >> > Dear Randy:
                                    >> >
                                    >> > As the "three out of four bites" statement represents an estimate by
                                    >> > Nabhan and Buchmann why not ask them how they arrived at it? What data did
                                    >> > they use? Surely, they consulted Free's "Insect Pollination of Crops"
                                    >> > (1970). Does the information in that book remain valid today?
                                    >> > Self-pollinating breeds of soybeans may have replaced bee-pollinated breeds.
                                    >> > On the other hand, Free wrote the book before Armstrong did all that work on
                                    >> > the pollination of domesticated and wild nutmegs.
                                    >> >
                                    >> > Meanwhile, there are plenty of literature reviews on pollination by
                                    >> > specific animal groups. Ask Dr Inouye for a copy of his most recent,
                                    >> > multi-authored review of fly-pollination. Why not find and read them before
                                    >> > estimating anything at all? Bioinformatics looks impressive but won't solve
                                    >> > much in this case as we don't know the pollinators of most of the angiosperm
                                    >> > species on this planet and, NO, I won't estimate the number of unstudied
                                    >> > angiosperm species. Perhaps readers need to be impressed by our sheer
                                    >> > ignorance and remind them that only a few people have attempted scientific
                                    >> > analyses of the ecological service we call pollination since 1793.
                                    >> >
                                    >> > Peter Bernhardt
                                    >> >
                                    >> >
                                    >> > On Sat, Nov 16, 2013 at 4:31 AM, Mitchell,Randall J <rjm2@...>
                                    >> > wrote:
                                    >> >>
                                    >> >>
                                    >> >>
                                    >> >> I agree that answering Crystal's question about relative importance of
                                    >> >> pollinator groups properly will require much more context and precision. But
                                    >> >> I think that misses the real question - what can we tell an interested and
                                    >> >> concerned public audience about the importance of the big 4 pollinator
                                    >> >> groups in general, so they have some tools to think about a topic that is
                                    >> >> new to them.
                                    >> >>
                                    >> >> For example, the '3 out of 4 bites depend on a pollinator' statement is
                                    >> >> very commonly used, and although it obviously depends on a number of general
                                    >> >> assumptions, it helps to put the issue into a context the public can
                                    >> >> understand. (the best estimate I know of is a bit higher - 87%: Ollerton,
                                    >> >> J., R. Winfree, et al. (2011). "How many flowering plants are pollinated by
                                    >> >> animals?" Oikos 120: 321-326.)
                                    >> >>
                                    >> >> When talking about this topic in public a forum I often point out that
                                    >> >> for crops, 71 of the top 100 crops depend mostly on bees (Nabhan, G. P. and
                                    >> >> S. L. Buchmann (1997). Services provided by pollinators. Nature's services:
                                    >> >> societal dependence on natural ecosystems. G. C. Daily. Washington, DC,
                                    >> >> Island Press: 133-150.).
                                    >> >> Although this statement doesn't directly apply to wild plants, it gives
                                    >> >> a flavor of relative importance in one context, and lets the conversation
                                    >> >> move on to pollinators and the challenges they face in general.
                                    >> >>
                                    >> >> I think that providing a more technically correct answer than this
                                    >> >> slightly vague approach is not yet possible.
                                    >> >> Using pollination syndromes to infer the most effective pollinator has
                                    >> >> many difficulties, though it may provide another broad-brush starting point.
                                    >> >> Directly measuring the dependence on each potential pollinator of each
                                    >> >> plant is an enormous and difficult task (as pointed out by others in this
                                    >> >> thread), and doing so for all the species in a community (or larger area,
                                    >> >> such as a state) would be orders of magnitude harder. Meta-analysis of
                                    >> >> studies from different communities might eventually be useful - I don't know
                                    >> >> of any to date.
                                    >> >>
                                    >> >> For now, I think case studies and anecdotes will probably have to do,
                                    >> >> but might actually be enough for Crystal's audience.
                                    >> >>
                                    >> >> Randy Mitchell
                                    >> >>
                                    >> >
                                    >> >
                                    >>
                                    >>
                                    >>
                                    >>
                                    >>
                                    >
                                    >



                                    --
                                    Emily May
                                    Department of Entomology
                                    Michigan State University
                                    202 Center for Integrated Plant Systems
                                    East Lansing, MI 48824
                                    Lab: 517-432-9554
                                  Your message has been successfully submitted and would be delivered to recipients shortly.