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affinity of Thelomma occidentale for picnic tables

  • 15 Mar 2017 6:03 PM
    Message # 4669295

    My observations of Thelomma occidentale in western Washington include 6 on picnic tables near salt water, 2 on docks and boardwalks, 2 on driftwood and 1 on a fence. CNALH specimens from Oregon north include 6 on fences, 3 on driftwood, 2 on bark, and 1 each on several other substrates including a telephone pole. Bruce McCune mentioned that he sees it “most frequently on fenceposts in the Willamette and Umpqua valleys. It also used to grow on my house rooftop, when it was cedar shakes.” At Ways of Enlichenment Curtis Björk has posted a photo of it on “worked wood of a picnic table in lawn, near marine shore”.

    What would explain T. occidentale’s penchant for picnic tables. (Might observer bias contribute, one way or the other?) Many picnic tables are nutrient rich. Epizoochory via birds seems likely, although I have yet to find T. occidentale on wooden structures, fences, etc. near any tables with T. occidentale, Could it be via humans’ shirt sleeves? Some time ago I mentioned this to some people who were encouraging, but I didn’t follow through. Posting a few photos.

  • 17 Mar 2017 5:41 PM
    Reply # 4674303 on 4669295

    I'm loving your affinity for affinities Richard. :-D Continuing that theme, I have to wonder what is the propagules' affinity(s) to shirt sleeves, feathers, hairs, or other epizoochorial substrates?

     

    Here's where I propose a mechanism. :-O I propose electrostatic attraction. I actually came to this epizoochorial idea while pushing some seeds of Oxalis dillenii around with a strip of card stock in order to photograph them. I'd get them just about where I wanted them and Bang!; they would leap off the table and onto my little paper strip. Now a thing about Oxalis dillenii is that the seed capsules are explosive either through drying or touch, so I reasoned an animal brushing the capsules sets off the explosion and the rugged surface of the seeds cause them to acquire a static charge as they fly through the air and then the seeds cling to the animal's fur/hair/skin/feathers. Charge gets discharged later and seed falls.

     

    Soooooo, is it possible the propagules of lichens can take and hold a static electric charge and so facilitate their spread? 

    Last modified: 17 Mar 2017 5:42 PM | Roger George
  • 18 Mar 2017 9:44 AM
    Reply # 4675207 on 4669295

    I love Roger's response to Richard's observation! And, for introducing me to the word "epizoochorial".


    From Wikipedia:

    epizoochory (uncountable) (ecology) seed dispersal via transportation on the outside of vertebrate animals (mostly mammals)


    Thanks guys!

  • 19 Mar 2017 9:31 AM
    Reply # 4676461 on 4669295

    Very interesting idea of Roger’s which bears further looking into. Shirt sleeves would seem to be good for static electricity. (Something very infuriating for me is how slices of apothecia tend to fly off before I can get them to the water on a slide.)


    Roger also mentions the seeds’ rugged surface. Ascospores of Thelomma have “ornamentation: minute to coarse, consisting of irregular ridges, faint parallel ridges or irregular cracks” (Tibell and Ryan 2004 in Nash et.al (eds) Lichen Flora of the Greater Sonoran Desert Region, Volume 2). Does this promote epizoochory? Touching a mazaedium produces streaks of spores - https://www.flickr.com/photos/29750062@N06/5127487912/in/photolist


    Sidetracked from things I should be doing (I blame Craig). Instead looking at things like http://apbrwww5.apsu.edu/thompsonj/Evolution/types_of_seed_dispersal.htm which has many related terms. Anemochory and ballochory would apply to most lichen fungi. Also of interest are endozoochory, particularly malacochory (https://brage.bibsys.no/xmlui/bitstream/handle/11250/2429655/2010-02_Johan%20Asplund_(INA).pdf?sequence=1), ornithochory and anthropochory.

    Last modified: 19 Mar 2017 9:37 AM | Richard Droker
  • 19 Mar 2017 11:51 AM
    Reply # 4676594 on 4676461
    Richard Droker wrote:

    Very interesting idea of Roger’s which bears further looking into. Shirt sleeves would seem to be good for static electricity. (Something very infuriating for me is how slices of apothecia tend to fly off before I can get them to the water on a slide.)

     

    Roger also mentions the seeds’ rugged surface. Ascospores of Thelomma have “ornamentation: minute to coarse, consisting of irregular ridges, faint parallel ridges or irregular cracks” (Tibell and Ryan 2004 in Nash et.al (eds) Lichen Flora of the Greater Sonoran Desert Region, Volume 2). Does this promote epizoochory? Touching a mazaedium produces streaks of spores - https://www.flickr.com/photos/29750062@N06/5127487912/in/photolist


    Sidetracked from things I should be doing (I blame Craig). Instead looking at things like http://apbrwww5.apsu.edu/thompsonj/Evolution/types_of_seed_dispersal.htm which has many related terms. Anemochory and ballochory would apply to most lichen fungi. Also of interest are endozoochory, particularly malacochory (https://brage.bibsys.no/xmlui/bitstream/handle/11250/2429655/2010-02_Johan%20Asplund_(INA).pdf?sequence=1), ornithochory and anthropochory.


    Interesting shot of the spore streaks Richard. Skin, whether dry or oily, is very high (positively charged) in the triboelectric series. The wider the divide in the series, the greater the triboelectric effect when the materials come in contact.

    https://en.wikipedia.org/wiki/Triboelectric_effect#Triboelectric_series

     

    On the roughness, Wiki says, "For surfaces with differing geometry, rubbing may also lead to heating of protrusions, causing pyroelectric charge separation which may add to the existing contact electrification, or which may oppose the existing polarity. Surface nano-effects are not well understood, and the atomic force microscope has enabled rapid progress in this field of physics."

     

    They also say, "When separated, some of the bonded atoms have a tendency to keep extra electrons, and some a tendency to give them away, though the imbalance will be partially destroyed by tunneling or electrical breakdown (usually corona discharge)." So, I wonder if a way to investigate if seeds or lichen propagules acquire a charge when they separate from the parent, would be to look for coronae during the separation?

     

    Gonna take someone far more knowledgeable and better equipped than I to measure the static electric characters of such small entities, let alone the variation of those characters under different atmospheric, material, and temporal conditions.

     

    Electrostaticory dispersal? You read it here first. :-D

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