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

Re: [beemonitoring] Defending the Professional Honor of Male Bees

Expand Messages
  • Dave Green
    My impression was just the opposite. Males stopping to take an occasional sip of nectar for energy, would not make near as much contact with the pollen as the
    Message 1 of 8 , Jun 20, 2010
    • 0 Attachment
      My impression was just the opposite. Males stopping to take an occasional sip of nectar for energy, would not make near as much contact with the pollen as the females who are not only driven to gather pollen for their brood, but who actually move in such a manner as to maximize pollen gathering. Who hasn't seen a megachilid female "doggy paddle" through the stamens?

      By the same token, honeybees who are deliberately gathering pollen are much more effective pollinators than those who are gathering nectar, and only incidently contact the pollen. A honeybee who is deliberately gathering pollen modifies her behavior so as to maximize contact with the stamens, and since her time in each flower will be much more brief, likely will visit more total flowers.

      This is an important item in managing honeybees for pollination service, where one strives to maximize the amount of open brood (which requires pollen), as opposed to frames of sealed brood, nectar or honey. This impels the workers to seek out pollen sources, thereby increasing efficiency.

      Dave Green
      Retired pollination contractor
       
       
      ----- Original Message -----
       
      This is an interesting thought.  I would add this question.  Are perhaps males more effective pollinators in some circumstances since they retain the hairs of the females but would be less active in moving the pollen to the scopa and mixing it with nectar?  Thus untidy males (this trait has been retained throughout the entire animal lineage).... may be beneficial to pollination.

    • Richardson, Leif
      Hello, I have been interested in this topic too. A few other thoughts. Male bumblebees do not sonicate Vaccinium, Rosa, Cassia, Geum, Solanum, etc. They remove
      Message 2 of 8 , Jun 21, 2010
      • 0 Attachment
        Hello,
        I have been interested in this topic too. A few other thoughts. Male bumblebees do not sonicate Vaccinium, Rosa, Cassia, Geum, Solanum, etc. They remove far less pollen from these plants than buzzing females (if they visit them at all), but on the other hand, any pollen they pick up incidentally is not going back to the colony, and may end up on the stigmas of another flower. It would be interesting to know how males and workers compare in pollination of something they both like to forage on—goldenrods and asters for instance.

        I’m also curious about the effect of male bee territoriality on pollination… do aggressive male Anthidium keep pollinating flower visitors away from the plants they patrol?

        Leif



        Leif Richardson
        Ecologist
        Vermont Fish and Wildlife Department
        5 Perry Street, Suite 40
        Barre, VT 05641
        (802) 476-0128
        (802) 279-5320 (c)

        www.vtfishandwildlife.com/wildlife_nongame.cfm
      • Vincent Tepedino
        It seems to me that this is a far more complicated question than we presently have the data to resolve and that we ought to be up front about it. I believe
        Message 3 of 8 , Jun 24, 2010
        • 0 Attachment
          It seems to me that this is a far more complicated question than we presently have the data to resolve and that we ought to be up front about it. I believe that male bees, in general, certainly accomplish some pollinations, but I doubt that one male is equivalent to one female. Why? Because, while the males of many species patrol flowers, they do not VISIT nearly as many flowers per unit time as do females, at least not when I'm watching them. So, if you want to equate males and females, pollination-wise, then you have to make the argument that males make up for fewer flower contacts per unit time by spending a lot more total time patrolling, and occasionally visiting, flowers. While that may be true, I doubt it translates to more total flower visits over a day.

          As others have pointed out, females probably pick up more pollen per flower visit than do males, and are therefore more likely to have something to transfer. On the other hand, females are also far more likely to make many within-plant visits and to transfer pollen within plants; conversely, a far greater proportion of male visits are likely to be to different genets; so males may make a disproportionate number of cross-pollinating visits. This might be especially important for self-incompatible plant species. Males may also contribute to female cross-pollination effectiveness by forcing them to move more frequently between plants by harassing them when on the flowers.

          And then there's the question of how much of the pollen that's picked up by males actually stays on the body as they zip around from plant to plant. Conversely, females may be more likely to groom pollen off many contact areas, but then many males land on rocks, twigs, etc., where they also seem to be grooming. I know of no data that compares pollen on randomly captured male and female bodies.

          Anyway, it seems to me that the safest thing to say, until the data are at hand, is that males undoubtedly make some contribution to pollination, but at present it's unclear how much that contribution might be. I'd guess the importance of males as pollinators has a wide range and is greatly dependent on what plant group we might be considering.

          By the way, I think Jim Cane was trying to put together some lit data on this and he may have something more definite to say when he returns.

          Vince

          Vincent J. Tepedino
          USDA ARS (retired)
          Bee Biology & Systematics Lab
          Dept of Biology
          Utah State University
          Logan UT 84322-5310

          vince.tepedino@...
          435-797-2559
          435-797-0461 (FAX)

          -----Original Message-----
          From: beemonitoring@yahoogroups.com [mailto:beemonitoring@yahoogroups.com] On Behalf Of Richardson, Leif
          Sent: Monday, June 21, 2010 6:33 AM
          To: beemonitoring@yahoogroups.com
          Subject: Re: [beemonitoring] Defending the Professional Honor of Male Bees

          Hello,
          I have been interested in this topic too. A few other thoughts. Male bumblebees do not sonicate Vaccinium, Rosa, Cassia, Geum, Solanum, etc. They remove far less pollen from these plants than buzzing females (if they visit them at all), but on the other hand, any pollen they pick up incidentally is not going back to the colony, and may end up on the stigmas of another flower. It would be interesting to know how males and workers compare in pollination of something they both like to forage on-goldenrods and asters for instance.

          I'm also curious about the effect of male bee territoriality on pollination... do aggressive male Anthidium keep pollinating flower visitors away from the plants they patrol?

          Leif



          Leif Richardson
          Ecologist
          Vermont Fish and Wildlife Department
          5 Perry Street, Suite 40
          Barre, VT 05641
          (802) 476-0128
          (802) 279-5320 (c)

          www.vtfishandwildlife.com/wildlife_nongame.cfm

          ------------------------------------

          Yahoo! Groups Links
        • Doug Yanega
          ... We could probably be safe in saying that the situations in which males might be *superior* to females are rare, even allowing for specialized cases such as
          Message 4 of 8 , Jun 24, 2010
          • 0 Attachment
            Vince Tepedino wrote:

            >Anyway, it seems to me that the safest thing to say, until the data
            >are at hand, is that males undoubtedly make some contribution to
            >pollination, but at present it's unclear how much that contribution
            >might be. I'd guess the importance of males as pollinators has a
            >wide range and is greatly dependent on what plant group we might be
            >considering.

            We could probably be safe in saying that the situations in which
            males might be *superior* to females are rare, even allowing for
            specialized cases such as orchids and other flowers using
            pseudo-copulation. And just as certainly as we can state that certain
            bee taxa are going to be better pollen vectors than others (e.g.,
            Hylaeines are about as bad as they get), we can state that
            differential within-taxon dimorphism is also going to mean more of a
            discrepancy between males and females in some taxa than in others,
            and never in the males' favor. All in all, I wouldn't be confident
            with any overall estimate of male bee pollination contribution more
            ambitious than "minor with rare exceptions", and can't imagine that
            we'd ever gather data sufficient to do much more than quantify just
            how minor.

            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
          • Peter Bernhardt
            Dear Vince and Doug: This is interesting but the whole point of my original message was that it s time for us to help the public understand that the honeybee
            Message 5 of 8 , Jun 25, 2010
            • 0 Attachment
              Dear Vince and Doug:

              This is interesting but the whole point of my original message was that it's time for us to help the public understand that the honeybee drone's life is rather "atypical" when one considers the biology of over 20,000 bee species.  Unfortunately, the honeybee's "glamorous and bizarre" cycle is the only one the general public knows... vaguely.  We can change their impressions with hard facts and some humor.

              1) Fact, male bees of many species are commonly found taking nectar and other resources (see 3) from flowers.  Honeybee drones are not paying members of the much larger flower-visiting club.

              2) Fact, many flowers fail to offer edible pollen.  Bees don't go to most orchids, milkweeds and a wide number of flowers with long, tubular floral throats (see Goldblatt's work on pollination of African Iridaceae) for pollen.  Pollen "collection" by bees at such flowers is passive so males may be just as efficient as females.  In fact, Drs Meier, Arduser and I are now in the position to compare and contrast milkweed pollinaria loads attached to legs of male vs. female Anthophora abrupta and Xylocopa virginica.  We stumbled onto this and I want to expand the collection of data over the following two years.

              3) Fact, male bees don't always visit flowers looking for edible rewards.  Yes, we know males camp out at flowers to hunt incoming females but also consider the perfume flowers of Neotropical orchids, aroids and at least one nightshade tree pollinated by male euglossines exclusively,  Also, consider the male bees that pollinate orchids that look like female bees (Ophrys) or the flower offers the males a place to sleep at night (Serapias and "black" Iris spp. in section Oncocyclus).  Isn't it interesting that no one has found an orchid yet pollinated by male honeybees within the natural distribution of A. mellifera?

              4)  Fact, male bees probably carry less granular pollen than females but is that so important?
                   a) What if the flower's ovary contains only one ovule?  One viable grain on the stigma works as well as a dozen.  Please note that Dr. Weston and I counted pollen loads of male bees on Australian persoonias.  Most males carried less than 100 grains but consider the many flowers pollinated by flies the same size.  It would be good to do a pollen count of male bees and syrphids at the same plant species.  

              Peter

                   



              On Thu, Jun 24, 2010 at 6:22 PM, Doug Yanega <dyanega@...> wrote:
               

              Vince Tepedino wrote:

              >Anyway, it seems to me that the safest thing to say, until the data
              >are at hand, is that males undoubtedly make some contribution to
              >pollination, but at present it's unclear how much that contribution
              >might be. I'd guess the importance of males as pollinators has a
              >wide range and is greatly dependent on what plant group we might be
              >considering.

              We could probably be safe in saying that the situations in which
              males might be *superior* to females are rare, even allowing for
              specialized cases such as orchids and other flowers using
              pseudo-copulation. And just as certainly as we can state that certain
              bee taxa are going to be better pollen vectors than others (e.g.,
              Hylaeines are about as bad as they get), we can state that
              differential within-taxon dimorphism is also going to mean more of a
              discrepancy between males and females in some taxa than in others,
              and never in the males' favor. All in all, I wouldn't be confident
              with any overall estimate of male bee pollination contribution more
              ambitious than "minor with rare exceptions", and can't imagine that
              we'd ever gather data sufficient to do much more than quantify just
              how minor.

              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


            • Cane, Jim
              Folks- I can add some to the discussion, although Vince covered the factors admirably. From my own data and an unpublished literature survey, males are
              Message 6 of 8 , Jun 28, 2010
              • 0 Attachment

                Folks- I can add some to the discussion, although Vince covered the factors admirably.  From my own data and an unpublished literature survey, males are inferior to females in their pollination efficacies at individual flowers, but they do deliver are some substantial fraction of it.  Thus, for instance, male Megachile rotundata and Nomia melanderi are about 2/3 as likely to trip an alfalfa flower as a conspecific female ( I can send the reprint pdf).  Contrast that with a honey bee, which is about 4%, as I recollect.  Having stated that, of course, exceptions will be found.  I am working out the energetics of flight for male Nomia to estimate their daily nectar needs, and so visits to alfalfa flowers for nectar.  It appears that they contribute no more than 10% to the full yield of cultivated alfalfa (but then that is close to the grower’s profit margin), mostly because they only need nectar to fuel their flight, as Vince points out, so they don’t visit that many flowers in a day.  Blair Sampson and I have a paper in revision that shows that male Peponapis can contribute substantially to fruit production at Cucurbita, but then, that is where they hunt for females as well as forage.  The whole topic warrants more study.  And then there are no doubt indirect effects, like male bee attentions driving females to other individual plants (or on alfalfa, it seems, to entirely different more distant fields!).  It is nothing to proud of, but it is a straw to grasp at least!

                 

                Yours,

                 

                jim

                 

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

                James H. Cane

                USDA-ARS Bee Biology and Systematics Lab

                Utah State University, Logan, UT 84322 USA

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

                email: Jim.Cane@... 

                http://www.ars.usda.gov/npa/logan/beelab

                http://www.biology.usu.edu/people/facultyinfo.asp?username=jcane

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

                 

                "The obscure takes time to see,

                but the obvious takes longer"
                Edward R. Murrow

                 

              Your message has been successfully submitted and would be delivered to recipients shortly.