Positive feedback in "ornaments" in animals implies that females have genes for "bigger than" ie. abstraction?

Question

In the blind watchmaker Dawkins when citing Fischer talks about positive feedback in arms races and that the genes for sexual preference and ornaments are linked and this often leads to escalation; so far so good. Does this imply, however that the notion of female sexual preference is linked to a tendency towards abstraction i.e. "bigger or brighter" is always better? Surely preferencial sexual selection must act upon males that already exist in the population or are there genes coding for "infinitely" big or bright is best?

Answer 1

Several points (I assume you are a serious questioner, not a creationist troll).

The idea is considerably older than Fischer. Darwin's "Descent of Man" is subtitled "and Selection in Relation to s*x".

You don't need a gene for the abstraction of "bigger than"; merely a stronger attraction to the bigger when both are present.

Any kind of selection operates both on genes already existing in the population (and healthy wild populations are genetically diverse), and on mutations that come into existence from time to time.

Zahavy argues that part of the positive feedback loop is that only the healthiest males are vigorous enough to support the exaggerated features.  It has also been argued that sexual selection is a factor favouring increasing brain size in cetaceans, some birds, and hominids.

Answer 2

I'm not exactly sure what your question is, but the link is not to an abstraction (bigger, brighter, etc.).  "Ornaments" in animals (and humans too, for that matter) signal the animal's state of health and fitness. For example, bright plummage in birds is indicative of low parasite infestation and general good health (as the bird obviously has been successful in finding sufficient food sources, allowing him to expend extra energy on preening). The "arms race" can be summed up as follows: In the beginning  females who chose to mate with male birds with low "ornament" value were less successful in reproducing and raising the chicks to reproductive age, thus decreasing the gene pool  for sickly genes. Those females who had the genes that led them to be attracted to high "ornament" males were more successful in reproducing and raising the chicks to reproductive age, thus increasing the gene pool for high ornament males and high "ornament" attracted females. There is of course a limit. High "ornaments" come with a price. Being too bright or too big becomes maladaptive, leading to increased predation,  inability to compete effectively for resources etc. (imagine a bull moose with huge antlers not being able to navigate through the woods to feed or a peacock whose tail  is so enormous he can't fly or effectively hide to escape predators). I hope this helps.