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3354Re: [beemonitoring] Monarchs/Butterflies/Skippers as pollinators

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  • Peter Bernhardt
    May 15, 2014
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      What we have here, unfortunately, is a lot of opinions based on little research and some general observations.  We DON"T have lots of papers that show that monarchs pollinate Asclepias species.  We do have papers and observations showing that the adults take nectar of milkweeds. Unless you record the removal of pollinaria by these butterflies (and how they carry it on their bodies) you can not discriminate a floral forager or nectar thief from a true dispersal agent of Asclepias pollen.  To date, the single publication by Betz and associates provides the best of a rather meager story.  Furthermore, the literature on pollination of Asclepias, in general, is also very poor because we still don't know which pollinators are most like to forage, in such a manner, that the pollinaria they carry will be inserted into a stigmatic slot.  This same problem concerned the great botanist, Robert Brown, in the 19th century.  He described the biomechanics of pollinarium removal, anatomy and successful pollination but didn't consider who did the best job as pollinator either.  Perhaps this era of videos will solve it eventually.

      Meanwhile, it's nonsense to dismiss monarchs as significant pollinators of non-milkweed species until we start catching them and analyzing them for pollen on the mouth parts, legs and - in some case - their wings.  Yes, they are generalized foragers but... so what? So are most North American bumblebees as queens and workers and the literature shows they are the primary pollinators of many native plant species.  Yes, monarchs only feed on nectar but... so what?  Hummingbirds consume floral nectar (they don't actively collect and swallow pollen) yet 50 years of field and lab studies show they pollinate many native species.  Yes, monarchs visit a lot of flowers with small, generalized, short tubes (Asrteraceae) but... so what?  We still don't have studies that show that a tiny, halictid bee (5-7 mm) in length is automatically a better pollinator of autumn Solidago and Aster compared to a big, galumphing monarch with those big fuzzy feet.  It doesn't matter which insect takes most of the the pollen.  It does matter which insect takes significant grain loads AND consistently dumps viable grains on receptive and compatible stigmas.  

      Let's look at the hard facts for now.  Those monarchs have two migratory periods and those migrations cover different parts of North America at different times of the year.  It doesn't matter which way the monarchs travel because, with each migration, different plant species are in bloom.  I can live with the idea that, in both cases, monarchs are always parasites of vernal and autumnal systems based on interactions between wildflowers and their TRUE pollinators but... where's the proof? 

      Please check your files and old emails for the report I sent to all of you about a year ago.  Monarchs don't pollinate the rare, Asclepias meadii in Kansas or Missouri but we weren't paying any attention to that butterfly as it foraged on other spring prairie plants.  Note, within that same report, all the species in flower while A. meadii bloomed and monarchs foraged and laid eggs.  


      On Thu, May 15, 2014 at 11:44 AM, 'Rutkosky, Flavia' Flavia_Rutkosky@... [beemonitoring] <beemonitoring@yahoogroups.com> wrote:

      Sam (and everyone else)

      Almost a year ago (27june2013) I posed the question of monarchs as pollinators to Delores Savignano  who then asked Donita Cotter what info she had re monarchs as pollinators.  Donita recalled asking the question around 2009 when FWS began work on the North American Conservation Plan and development of the Monarch Joint Venture.  The info she received was that monarchs are probably not, or not known to be important pollinators.

      Donita referred me to several other folk - Chip Taylor (Monarch Watch), Mace Vaughan (Xerxes Society Pollinator Program Director) and Karen Oberhauser (Monarch Joint Venture) to find out if additional research had provided other information re monarchs and pollination.

      I then contacted them and received the following replies. . .

      Chip's response (28June2013):

      I have seen monarchs covered with pollen on several occasions and pictures of same. I don't know the flowers they were visiting but would guess it was a lily in one case.

      Generally, monarchs would be considered poor pollinators or, let's say, inefficient pollinators. They are not designed for pollination yet some pollination is surely achieved by their visits to flowers.

      Because of their numbers, especially in some areas at certain times of the year where flower visitation is intense, it is likely that pollination is more than trivial.

      Like most incidental pollination, the effectiveness of pollination is likely to be a function of floral structure and the intensity of foraging.


      Mace's response(28June2013)

      I asked around to my monarch team. Overall, we concur with Chip that monarchs visit a wide variety of plants for nectar and that there is little documentation of their importance as pollinators of any given plant species.


      The one group of plants for which we know there is some documentation of the monarch’s role as a pollinator are milkweeds!  Countless milkweed pollination studies have been done, due to their unique pollination mechanism, and we know that pollinia transfer by monarchs has been mentioned in a few of them.


      There are certain native plants that are considered to be very important for fueling the monarch’s fall migration, but we don’t think anyone has a clear picture of what their favored nectar sources are throughout the year and across the country, nor the role that the butterflies might be playing in pollination. In the south-central US, frostweed (Verbesina virginica) and blue mistflower (Conoclinium coelestinum) are considered to be important late summer/early fall nectar sources for monarchs. Other plants readily visited by monarchs include Liatris spp, goldenrods in the fall, but no evidence that monarchs are an important pollinator. They could be relatively valuable pollinators of Lobelia cardinalis (in addition to hummingbirds), and possibly Liatris ligulistylis. Without doing a lit search, we would be just guessing here. Even then, I doubt there has been much research to begin with.




      Karen's response(28June2013):

      Another reason that monarchs are probably not important pollinators is that, like most butterflies, individuals are such generalists.  They go to many flower species, probably dropping pollen from one species onto another. However, as Chip says, they probably do transfer a non-trivial amount of pollen to the "right" species under some circumstances.  


      . . .so that is what I know from my question re monarchs and pollination.


      On Wed, May 14, 2014 at 3:52 PM, 'Droege, Sam' sdroege@... [beemonitoring] <beemonitoring@yahoogroups.com> wrote:


      [Disclaimer, of sorts:  I like butterflies and have studied butterfly survey techniques in the past and own 2 pair of butterfly binoculars]

      The feds are revving up to start a pollination campaign... the details of which are currently being worked out.   This is a good thing and almost any directive will be positive.  That said, I have seen some preliminary information from the Department of Interior with a lot of Monarch efforts being mentioned/highlighted.

      Monarchs definitely are in trouble and certainly a general pollinator effort should involve monarchs and other butterflies as the umbrella is large and butterflies are generally more charismatic than the rest. Additionally, both Monarchs and other pollinating groups would benefit from the long coat tails of each other's charms.

      However, in giving talks I have found myself generally poo-pooing (to use a technical term) butterfly and skipper pollination contributions to floral reproduction. 

      But, how true is that?

      So I ask 3 Questions from small to large: 

      1.  Are monarchs transferring pollinia effectively on Milkweeds?
      2.  Are monarchs significant pollinators in any situation?
      3.  Does the average skipper and average butterfly play much of roll in pollination?  Skippers are low slung enought that one would suspect they are better than butterflies...



      See....Internet quotes about Monarch pollination at the end of this email.

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

      The lepidopterist with happy cries
      Devotes his days to hunting butterflies.
      The leopard, through some feline mental twist, 
      Would rather hunt a lepidopterist.
      That's why I never adopted lepidoptery.
      I do not wish to live in jeopardoptery.
                -  Ogden Nash


      Interesting Quotes from the Internet

      Monarch butterflies help to pollinate our food, especially corn!

      monarch butterflys do NOT spread pollen, because they lay their eggs on milkweed which is a non pollinated plant. the actual butterfly itself only lives for a day and its only purpose is to lay eggs. butterflys (caterpillars) are born with the eggs, and there are no "male" butterflys.... hope this helps!

      . Like most butterflies, monarchs are pollinators that play an important ecological role in maintaining biological diversity.

      If the Monarchs become extinct, what happens to the other pollinators we depend on?

      Monarch butterflies pollinate many plants, 

      Bees are Not Optional
      Apes sunt et non liberum

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