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UltravioletPhotography

Vision in ultraviolet wavelengths - some remarkable possibilities


rfcurry

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I'm not sure where this thread belongs.

 

We know that every family of birds tested has vision in the UV, but now we are learning that many mammals may also.

Here are some old tables about birds. You would expect that if a bird has UV reflective markings, he would also have UV vision.

 

http://overmywaders.com/images/Birds_Page_2crop.jpg

 

http://overmywaders.com/images/Birds_Page_6crop.jpg

from Ultraviolet Vision in Birds: What is its function?

Bennett and Cuthill (1993)

 

You might be surprised by the recent work on mammals --

http://overmywaders.com/images/UVinMammals-2014-Douglas-_Page_4.jpg

 

http://overmywaders.com/images/UVinMammals-2014-Douglas-_Page_5.jpg

 

More later.

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Thanks for posting this, Reed!

 

One thing that stands out for me (since I am involved in anthropological sciences in particular), is the irony demonstrated between some Carnivora listed as being more UV-sensitive than many Primates.

 

How can this be, one might ask, if Carnivora supposedly depend much less on plants as food sources, compared to many Primates who actually integrate a good portion of plant-derived foods into their diets ... and yet, the Primates are somehow more "blind" to UV, compared to Carnivora?

 

Of course, we can also assume that Carnivores could implement their "UV vision" to disseminate other vital information, such as being able to distinguish their choice prey over other, less-preferred prey. Or being capable of spotting hidden prey amid certain cover ("camouflage"). After all, we already know that various animals can also display significantly different and unique patterns under UV-A energy, compared to Visible.

 

So, there can be any number of alternate dynamisms which have facilitated the evolution of certain radiation-sensing ranges, when it comes to visual information.

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One thing that stands out for me (since I am involved in anthropological sciences in particular), is the irony demonstrated between some Carnivora listed as being more UV-sensitive than many Primates.

 

How can this be, one might ask, if Carnivora supposedly depend much less on plants as food sources, compared to many Primates who actually integrate a good portion of plant-derived foods into their diets ... and yet, the Primates are somehow more "blind" to UV, compared to Carnivora?

 

And why would UV vision in mammals be correlated to the presence of plant-derived foods in their diet?

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For potentially similar reasons to why UV vision in some aves is believed to correlate to plant-derived foods in their diet.

 

However, obviously though, this trend doesn't seem to extend into mammalia, given the charts provided. And this could make some reasonable sense, since most leaves, roots, shoots, and tubers (the primary dietary materials of many primates) remain unspectacular in UV-A, unlike flower patterns.

 

(It should also be considered that the majority of primates are actually omnivores, and not strict herbivores. Perhaps it is such dietary diversification - opportunistic omnivorism prevailent within the majority of the primate order - which may have downplayed any evolutionary stressors to develop extended vision into the UV-A in order to help with locating specific types of food. Indeed, primates have among the most diverse diets within animalia).

 

Although it should also be acknowledged, though, that the incidence of correlation (or even a lack of it) does not necessary equal causation.

 

Curious, though, how reptilia would stack up, here. I do not see any reptiles amongs these charts.

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For potentially similar reasons to why UV vision in some aves is believed to correlate to plant-derived foods in their diet.

 

Would you mind pointing me to specific references? Thanks

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Which references, in particular? That the majority of the primates exhibit among the most diversified and opportunistic omnivorous diets within the animal kingdom?

 

That's common biological knowledge which can be looked up and verified across many available texts.

 

But, if you want me to dig into some of my own references, then I would be happy to. It's just that I am not home right now, and typing from phone. But, I will be glad to pull out some of my biology books from my home library (left over from the course curriculum materials of my fields of study), as soon as I get home.

 

No problem. Thanks!

 

(Or are you asking me for reference of another matter?)

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Ahhh. Never mind. I didn't see your quote, above, when I first read your response.

 

Well, hummingbirds, for example: Are they not hypothesized to be attracted to certain flower patterns visible under UV-A?

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Reference for your hummingbird statement?

 

Most of the flowers I have seen hummingbirds visit do not have any patterned UV-signature.

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I see. So, then, bird feeding behavior is NOT ever influenced by UV markings on flowers, then?

 

Ok. I had the distinct impression that this was what was being proposed, by this site? Looks like I misunderstood what was being taught by this website, concerning UV flower patterns.

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Also, by your own example, I would like to point out that I have seen plenty of bees and butterflies also land on various flowers with no known UV patterns, just the same.

 

What this demonstrates for me as that exclusional behavior doesn't necessarily rule out inclusional behavior. It could be a complex mixture of both, depending on opportunity.

 

So, my next question would be: By what testing methodology has it been determined that bees and butterflies are attracted to certain UV patterns on flowers, while birds are not? What are the factors of ruling this out, short of being inside of the mind of the animal, itself, and knowing its true intentions?

 

And if we cannot be certain, based on existing knowledge, then maybe we should be questioning the premise that UV flower patterns play any role in animal signaling, at all?

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We have barely accepted that many animals can see in the UV, it may take another twenty years to determine why each species evolved (or re-evolved) UV sight.

Here is a study done on the preference of Kestrels in choosing not just the species of vole, but the gender and health of said supper.

 

http://www.researchgate.net/publication/236947780_Kestrels_prefer_scent_marks_according_to_species_and_reproductive_status_of_voles/file/3deec51a8b9713f992.pdf

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Thanks for that link, Reed.

 

You know, it just hit me: The evolutionary lineage of all mammals is believed to trace backwards to a convergence period when anamniotes (water-dwelling vertebrates which produce eggs) first led to the rise of amniotes (first terrain-adapted vertebrates which produce eggs).

 

In other words, all mammals are theorized to fist come from the water, before they ever became land-dwelling ... synapsids being among them. And as of today, all mammals are the only remaining extant synapsids (non-extinct). Other synapsids went extinct, during the "great dying off" during the Permian-Triassic extinction (which is known to be the largest mass-extinction event within Earth's entire time-line).

 

Being as such, then, it would stand to reason that all proto-mammals (the evolution from anamniotes to amniotes) first started out as being "blind" to UV radiation, since water-dwelling animals would have little to no use for detecting UV (or so, that is what I understand, at least).

 

Thus, I feel that in order to begin to approach and gain insight into the evolution of UV-adapted vision, we should look at this study from the position that UV-capable vision was initially completely absent from all our proto-mammal ancestors, and not because some mammals have "gained back" an ability from a prior progeny. In other words, abilities gained in UV-sensitive vision among some mammals most likely run in a linearly single direction, from less to more, based on evolutionary knowledge. There probably isn't any "re-gaining" going on. Just gaining.

 

However, I would be curious to see the charts above extended into testing the UV-transmissive properties of eyes belonging to water-dwelling animals which exist today, just to confirm my assumption.

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Andrea: Most of the flowers I have seen hummingbirds visit do not have any patterned UV-signature.

Igor: I see. So, then, bird feeding behavior is NOT ever influenced by UV markings on flowers, then?

 

I do not know. I've mostly read about bees. My one observation makes neither an hypothesis nor a generalization about birds and their UV vision w.r.t. feeding behavior. I'm mostly here to do UV photography. And, on occasion, keep threads from veering off the rails.

 

Igor: I had the distinct impression that this was what was being proposed, by this site?

Looks like I misunderstood what was being taught by this website, concerning UV flower patterns.

 

To the extent that UVP is teaching anything, it would be teaching about UV photography. There's no one here to my knowledge is teaching anything about bird feeding behavior.

Igor, you are always weirding me out.

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Well ... but, then again. Threads can also be designed to explore additional posibilities. Science doesn't learn new things and gain additional insight, by remaining complacent, does it? :)

 

I think the topic of this thread actually has remained on-course, considering the topic material of the initial post. Otherwise, why even bother having a thread, if discussion is discouraged?

 

Agreed, though, that other threads have NOT remained as on-course as this one. Haha.

 

(Which is precisely why we have attentive moderators, such as yourself. Thank you for all you do to maintain that vital order of things, where and when we need it.)

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And, of course, UV-reflected visual science / analysis - pertaining to how it applies to biological systems - is still quite a relatively fledgeling field, isn't it? Just as Reed pointed out.
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I didn't think we were doing science either, but I'm probably wrong.
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What is science, if not starting with an experiential "hunch" or "premise" first ('hypothesis') based on existing empirical knowledge / evience .... then followed through into the formulation of a working 'theory', through additionally-gathered and organized supporting evidence that gains peer-review through uniformity in testing and duplication of results?

 

And as my last "hypothesis" stands, I wish to see some UV-transmissive testing done on the eyes of water-dwelling animals, before I move on to more assertive hunches.

 

But, until or unless that happens, thanks all for this thread!

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And, of course, UV-reflected visual science / analysis - pertaining to how it applies to biological systems - is still quite a relatively fledgeling field, isn't it?

 

I have some references from the 1920s, so the investigations are at least 90 years old.

 

1924: A. Kühn related UV reflections from flowers to UV sensitivity in insect vision.

  • Kühn, A. (1924). Zum Nachweiss des Farbunterscheidungsvermögen der Bienen. Naturwissenschaften 12, 116.
  • Kühn, A. (1927). Über den Farbensinn der Bienen. Z. Vergl. Physiol. 5, 762–800

1925: H. Wolff demonstrated UV sensitivity in minnows.

  • Wolff, H. (1925). Das Farbunterscheidungsvermögen der Elritze. Z. Vergl. Physio. 3, 279-329.

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I don't consider 90-year-old data as a "mature science" ... when Galileo Galilei was already looking at moon craters, nebulae, and galaxies, and confirming Copernican heliocentrism, as far back as the start of the 1600's.

 

Or even more related to our topic: Joseph von Fraunhofer was already observing spectral lines within radiation, back in the early 1800's.

 

But, then, everything is relative, of course.

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But, then, everything is relative, of course.

Sayeth Einstein.

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http://www.sciencedaily.com/releases/2013/02/130211090928.htm

Birds evolved ultraviolet vision several times

Date: February 11, 2013

Source: BioMed Central Limited

Summary:

 

Ultraviolet vision evolved at least eight times in birds from a common violet sensitive ancestor finds a new study. All of these are due to single nucleotide changes in the DNA.

Journal Reference:

  1. Anders Ödeen, Olle Håstad. The phylogenetic distribution of ultraviolet sensitivity in birds. BMC Evolutionary Biology, 2013; 13 (1): 36 DOI: 10.1186/1471-2148-13-36

*****

The leading theory regarding the evolutionary selection of UV vision in select fish species is due to its strong role in mate selection.

  1. Kodric-Brown, A., & Johnson, S.C. (2002). Ultraviolet reflectance patterns of male guppies enhance their attractiveness to females, Animal Behaviour, 63(2), 391-396.

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Fascinating, Andrea!

 

This would be precisely the type of information that would pertain to what I was interested in exploring. Thank you for this!

 

I will read it in its entirety, tomorrow, as soon as I am on lunch-break ... because I have an early rise for the start of my work-day (4:15 am).

 

So, I need to get in the sack, right now!

 

I will get back to you, concerning this subject, and my impressions of this linked article. Thank you, once again!

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