Guillaume Gomard wrote: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.
No problem, Guillame. I like having these discussions as well and exactly because a lot of things that are being discussed are hard to prove or not proven yet I'm using phrases like "I think" and "it seems". Still no harm in talking about it.
Mario Schweiger wrote:DOI: 10.1007/s00265-012-1412-6 = PDF-10898 in db
Yes, thanks Mario! From this perspective it makes more sense for me personally.
There's been some interesting info from all of you guys. Just to summarize, it looks like the blue colouration is correlated to:
- presence of females
- presence (and number) of other males
- weather
- water temperature
It is not correlated to:
- physical fitness
Could it be that some of the factors correlating with the blue colouration have to do with the physical process of turning blue (any publications on this?) rather than the behavioral aspect of it, e.g. they might need certain temperature and conditions to change colour...?
For me one thing is sure neither the calling nor the colouration has anything to do with a female's choice of an individual male, simply because she obviously doesn't have such choice.
So far the best we have is that in breeding masses with males greatly outnumbering females it would be useful for males to turn different colour so they don't waste time and energy by trying to mate with other males. However, even if this is so I don't think it stops males of trying to dislodge other males that are already in amplexus with a female. There's one thing I find a bit unsettling with this scenario - male frogs and toads of explosive breeding species have been known to go into amplexus not only with other males but also with dead females, dead fish, salamanders, other frog species, bottles and other objects...one male Bufo bufo even grabbed my hand as I was trying to catch him (they squeeze quite hard). So how just a visual cue like colour would help a male who can't tell the difference between a female and a dead fish to distinguish between sexes? Which also makes me wonder what is a frog's perception of others of its kind? Surely there must be other, maybe chemical cues for a male to recognize a female, or not...?