JFDee
Senior Member.
A new article on a 'Carnicom Institute' site tries to make the case that samples sent to CC from all over the world are not threads made by ballooning spiders. However, on first glance the only indication for this is that they look a bit different when compared to self-collected spider webs under a microscope. No chemical analysis provided so far.
Screenshot from the article:

Quote from the article:
https://carnicominstitute.org/wp/global-validation/
The occasion for that article seems to have been a recent ballooning event reported by Terry Lawton from Wexford. See post #15 for details about this video.
Discussion:
It is not very obvious from the images on the site that there is an optical difference between the 'normal' spider webs and the 'filament' sample. However, even if it were - there are significant differences between threads in a normal spider web and the threads used for 'ballooning'
Ballooning threads consist only of a certain type of silk, produced by the so called ampullate glands (the majority of spiders has several different types of silk glands). The ampullate silk is also used as a 'life line' (constantly attached during movement) and for 'bridging' (connecting wide gaps with wind support). In webs, it appears only in the 'framework'. One important property is that it is less sticky than silk from other glands.
Consequently, it is to be expected that the micro-optical properties of threads from a collected web and 'balloon' threads are different - even if they came from the same species of spider.
In this case however, neither of the species producing the samples is known in the first place, so the comparison does not make much scientific sense at all.
Reference:
Spider Physiology and Behaviour, Jérôme Casas (ed.), Academic Press, 2011. Excerpt:
Pg. 190, retrieved from Google Books
The specific chapter of the book is available (but probably unintentional, as it's not free):
http://ezlab.zrc-sazu.si/uploads/2011/10/Blackledgeal2011_Review-OrbWebs.pdf
[appended with information from the following posts]
See also this thread: Debunked: Chemwebs / Mysterious Fibers fall from sky (ballooning spiders)
Screenshot from the article:
Quote from the article:
The occasion for that article seems to have been a recent ballooning event reported by Terry Lawton from Wexford. See post #15 for details about this video.
Discussion:
It is not very obvious from the images on the site that there is an optical difference between the 'normal' spider webs and the 'filament' sample. However, even if it were - there are significant differences between threads in a normal spider web and the threads used for 'ballooning'
Ballooning threads consist only of a certain type of silk, produced by the so called ampullate glands (the majority of spiders has several different types of silk glands). The ampullate silk is also used as a 'life line' (constantly attached during movement) and for 'bridging' (connecting wide gaps with wind support). In webs, it appears only in the 'framework'. One important property is that it is less sticky than silk from other glands.
Consequently, it is to be expected that the micro-optical properties of threads from a collected web and 'balloon' threads are different - even if they came from the same species of spider.
In this case however, neither of the species producing the samples is known in the first place, so the comparison does not make much scientific sense at all.
Reference:
Spider Physiology and Behaviour, Jérôme Casas (ed.), Academic Press, 2011. Excerpt:
The specific chapter of the book is available (but probably unintentional, as it's not free):
http://ezlab.zrc-sazu.si/uploads/2011/10/Blackledgeal2011_Review-OrbWebs.pdf
[appended with information from the following posts]
See also this thread: Debunked: Chemwebs / Mysterious Fibers fall from sky (ballooning spiders)
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