Catalyst Program

[Tintola]

For those who haven't seen this yet, http://www.abc.net.au/catalyst/stories/2589683.htm A very complex little creature.

[arthur]

And its all because of climate change . . amazing

Now only a fool would deny that the climate is changing . .

But some of the claimed causes, and some of the alleged effects certainly stretch the credibility


All in all a very interesting clip . . Thanks for posting

[finches247]

Great Clip Thanks for sharing

[Tintola]

Seems to me that there are still a couple of unanswered questions;

1. How does the hen know what head colour she is herself? Or is it instinctive or genetically set? and

2. Why is it that in the wild population, Black-headed birds are the most abundant, when the Red-headed morph is dominant genetically?

Anyone know these answers?

[Tiaris]

I find the conclusions drawn in this to be very dubious indeed.

Tintola, I asked your second question to Sarah Pryke at the last finch convention and was basically told that red-headeds are such aggressive and highly strung birds that their stress hormones override their DNA to result in them not producing offspring as you would expect from their dominant mode of inheritence.
If you believe that, you probably also find many of the other findings in this story totally plausible. I certainly do not.

[finchbreeder]

It would appear that the research is done only with BH and RH. No YH are used?
LML

[Netsurfer]

But that's nothing new, I remember reading something similar before on this subject that the female prefers black-headed males. Stella Lorikeets are similar (2 forms) red and black and the Gouldian finch comes in 3 forms both species have very long tails feathers.

[arthur]

[quote="Tintola"]1. How does the hen know what head colour she is herself? quote]

How does one know that she does know . . .

Perhaps she saw her father and knows that if she wasn't the same head colour as he, then she would be a he and not a she ??????



Academics devise solutions to problems that will never exist





Anyway it was an interesting clip

[BrettB]

1. How does the hen know what head colour she is herself? Or is it instinctive or genetically set? and

As I am sure most are aware, no-one really knows the answer to this. However, theoretically at least, it is not really necessary for the hen to know what color she is, only that she has a preference for a particular color. Then, assuming that "mixed marriages" are less successful than same head color pairings (and I know this is not agreed by a lot of people), you would end up over time with a populations of black heads that prefer black heads and red heads that prefer red heads. Those black heads that preferred red heads and vice versa would be less successful at breeding and reduce in frequency .

Lots of ifs and buts, but it is plausible.

Cheers
Brett

[Danny]

The obvious answer to the first part is they look at themselves in the water when the come to the waterhole to be counted.

They are not alone in the second part - There are other species in which the genetically dominant species does not dominate phenotypically.
The same occurs in Bells Phase (heavy bands) Lace monitors. I can't vouch for increased aggressiveness or reduced sperm counts but in them its a pure mathematical thing. If we consider the typical mating interactions then on average a phenotypically Bells male (who is more likely to be heterozygous on average) is most likley to meet either a heterozygous Bell's (which are for some reason quite rare) or a homozygous normal female at mating resulting in the production of more heterozygous Bells and homozygous normal offspring and only a small proportion of homozygous dominant animals.Until such time as the homozygous dominant form can selectively mate with homozygous dominant forms, the recessive gene will always be present.