Anonymous asked in Science & MathematicsBiology · 1 month ago

If sexual selection favours brighter birds, how would it impact sexual/natural selection once a predator that feeds on them is introduced?

If female birds mate with brighter birds and choose them over dull ones, then sexual selection should favour brighter birds. But what would happen to this trend if a predator is introduced which feeds on them? Would this impact natural selection and sexual selection? Or only one of them? Or none?

6 Answers

  • CRR
    Lv 7
    1 month ago
    Favourite answer

    That can be answered by an experiment conducted on guppies in Trinidad where it was shown that guppy colour depended on how may predators there were.

  • 1 month ago

    The introduction of new predators into any ecosystem is problematic to "every other creature" in that ecosystem, regardless of it's color. Even other predatory species suffer when new predators are introduced, because they compete with them for prey. A brightly-colored bird that can "fly faster" than a duller-colored bird, might be less impacted by the new predatory species.

  • Anonymous
    1 month ago

    Why complicate a very simple theory.  Those which live longer, eat better and attract mates better will breed more often and have more offspring.  If that offspring is faster and/or less accessible and/or less attractive to the predator, it too will live longer and breed more often and have more offspring.

  • 1 month ago

    Unfair question.  Let's say that the introduced predator is "pig."  Well, the pigs don't care what color the birds are.  They eat ALL the eggs that are laid in ground nests.  There's little chance for "selection" of any sort to happen.  The pigs eat ALL the eggs.

    You can generalize this to most mammalian predators.  Most mammals are nocturnal.  "Brightly colored" is irrelevant since that's not going to show up at night.

    All right.  So let's suppose that the new predator is not very efficient, diurnal, has great color vision, and hunts by sight.  In that case, both natural selection and sexual selection are affected.  The duller birds are better at survival -- natural selection.  The females who choose a duller bird are more likely to reproduce successfully (birds typically are two-parent carers) -- sexual selection.


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  • ?
    Lv 6
    1 month ago

    They would select BACK the other way, ie sexual selection drives one way, predators drive them back. Google Birds of Paradise, which live in an environment sheltered from predators (relatively).

  • Anonymous
    1 month ago

    Many birds adapt by having bright colored plumages only during the breeding season and/or they have those bright colors on only a small part of the body (e.g. the red epaulet of red winged blackbirds) and the red color can also be partly concealed when the bird is not displaying them.. Peacocks have eyespots on their tail feathers. Those eyespots make the tail look like a large animal and real world studies show that peahens are actually more often caught and eaten by predators than the male peacocks. 

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