Why Rana arvalis turn blue?

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Re: Why Rana arvalis turn blue?

Postby Ilian Velikov » Sat Feb 25, 2017 1:30 am

Guillaume Gomard wrote:it would be interesting to check if someone ever tried to quantify this effect to figure out if it is significant, beyond the maybe misleading impression that one can get with "simple" observation in the field.


I wasn't trying to present a thesis here just wanted to share some thoughts and hear what other people might have thought about it, proven or not.Sorry if I've offended anybody.
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Re: Why Rana arvalis turn blue?

Postby Mario Schweiger » Sat Feb 25, 2017 8:50 am

DOI: 10.1007/s00265-012-1412-6 = PDF-10898 in db :)
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Re: Why Rana arvalis turn blue?

Postby Guillaume Gomard » Sat Feb 25, 2017 9:36 am

Ilian Velikov wrote:I wasn't trying to present a thesis here just wanted to share some thoughts and hear what other people might have thought about it, proven or not.Sorry if I've offended anybody.


There was absolutely no form of criticism in my answer, I just tried to make a point on the fact that it's probably hard to evaluate this effect without a proper analysis on energy loss. I hope I did not give the impression that this topic should be closed, since I really like this kind of discussion.
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Re: Why Rana arvalis turn blue?

Postby Berislav Horvatic » Sat Feb 25, 2017 5:20 pm

Jeroen Speybroeck wrote:Nuptial colours in males mainly serve to impress the ladies, I'd say.

Very helpful and revealing, indeed, regarding this particular issue... The final, sweeping solution
von oben herab. Thanks a lot. All clear. Case closed.
Guillaume (would have) said that much more gently, of course. But if he's sincerely interested in
a less sweeping, oversimplified solution, so am I. Let's wait and see.

P. S.
BTW, why have our avatar pictures disappeared recently? Not all, but most of them?
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Re: Why Rana arvalis turn blue?

Postby Berislav Horvatic » Sat Feb 25, 2017 5:42 pm

Mario Schweiger wrote:DOI: 10.1007/s00265-012-1412-6 = PDF-10898 in db :)

Thanks, Mario. This one is much more helpful for understanding.
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Re: Why Rana arvalis turn blue?

Postby Jeroen Speybroeck » Sat Feb 25, 2017 6:15 pm

An anecdote came to mind. Peter Engelen told me about a single male calling throughout the (short) season, yet never turning blue. Hardly the basis for an answer, but it did get me wondering - did he miss the drive of female attention to do his best, or was it the lack of competitors, or ... ?
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Re: Why Rana arvalis turn blue?

Postby Bobby Bok » Sat Feb 25, 2017 7:18 pm

I somewhere read that the amount of calling males certainly influences how blue they get, can't remember the source though :oops:
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Re: Why Rana arvalis turn blue?

Postby Mario Schweiger » Sun Feb 26, 2017 8:13 am

I've heard of populations (not here in Austria), where the males never turn into blue (max. to a glimpse of purple, like R. temporaria males). But could not remember who told/wrote this.
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Re: Why Rana arvalis turn blue?

Postby Jeroen Speybroeck » Sun Feb 26, 2017 10:48 am

Mario Schweiger wrote:I've heard of populations (not here in Austria), where the males never turn into blue (max. to a glimpse of purple, like R. temporaria males). But could not remember who told/wrote this.

I believe that happens here in years with poor weather, but not sure.
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Re: Why Rana arvalis turn blue?

Postby Jeroen Speybroeck » Sun Feb 26, 2017 12:32 pm

Here = Belgium.
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