For female yellowthroats, there's more than one way to spot a winning
mate

Date:
February 14, 2022
Source:
University of Wisconsin - Milwaukee
Summary:
One population of female common yellowthroats prefer males with
larger black masks, but another group of females favors a larger
yellow bib. A new study has found that both kinds of ornaments
are linked to superior genes.



FULL STORY ==========================================================================
For female common yellowthroats, beauty isn't just skin -- or features
-- deep.

New research provides evidence that large or showy physical features
of males attract females because they signal high-quality male genes,
such as those linked with robust immunity or stress resistance.


==========================================================================
This association has previously been unclear, particularly in
cases where females in different populations prefer different male
ornaments. Yellowthroats are small songbirds found throughout the U.S.

In comparative studies across two decades, researchers at the University
of Wisconsin-Milwaukee and Skidmore College have determined that different types of ornaments in male yellowthroats are linked to the same superior
genes that enhance survival of offspring.

The work was published Feb. 14 in the Proceedings of the National Academy
of Sciences.

Peter Dunn and Linda Whittingham at UW-Milwaukee tracked female
preferences for male ornaments in Wisconsin, while Corey Freeman-Gallant
at Skidmore College studied preferences in upstate New York.

"We found that the particular ornaments that females tended to prefer in
each of our locations didn't match," said Dunn, distinguished professor
of biological sciences, "even though both characteristics are found among
males in both areas." Females in the Wisconsin studies favored a large
black mask that extends across the eyes, while females in the New York population chose males with large yellow "bibs."


==========================================================================
To investigate this behavior, the researchers studied the genes of
feathers on birds with larger-sized features, using techniques that have
become feasible to use only in the last five years.

The verdict: Despite being produced by different pigments in different
parts of the body, the size of the ornament preferred by females in
each population was linked to numerous genes that govern beneficial
survival traits.

The findings don't explain why the females have different preferences geographically, Dunn said, but they have implications for evolution. The availability of more than one ornament as a mating signal allows females
to potentially respond to a different choice if their environment changes.

Very few researchers have examined the female appeal of male ornaments in different populations. For example, Dunn pointed to studies of swallows
that indicate that females prefer longer tails in some locations and
browner bellies in other areas.

Even fewer studies exist that explore the size of ornaments at the
genetic level, he said.

"With this study, we not only found genes related to ornaments, but
we also showed that similar genes can be linked to different types of
ornaments in different populations," Dunn said. "It brings us much closer
to understanding the function of ornaments." Though previous research
has assumed that ornaments were related to mate choice, Dunn says that had
to be proven because sometimes male ornaments are used for other purposes.

"What we consider flashy characteristics may not be limited to mate
choice. For example, they may be used in interactions between two males." ========================================================================== Story Source: Materials provided by
University_of_Wisconsin_-_Milwaukee. Original written by Laura Otto. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Nicholas D. Sly, Corey R. Freeman-Gallant, Amberleigh E. Henschen,
Piotr
Minias, Linda A. Whittingham, and Peter O. Dunn. Molecular
parallelism in signaling function across different sexually selected
ornaments in a warbler. PNAS, 2022 DOI: 10.1073/pnas.2120482119 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214154835.htm

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