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

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  • 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 1 of 8 , Jun 25, 2010
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      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.  



      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

      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.


      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)
      "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 2 of 8 , Jun 28, 2010
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        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!







        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@... 



        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


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