Flashy tails and sharp horns in the name of love


How evolution impacts courtship in the animal kingdom


 
A horned dung beetle collected by Professor Erin McCullough.

If love is a battlefield, evolution has given animals and insects the tools for competition. Peacocks boast flashy tails and birds sing to capture the attention of mates; meanwhile, elk and dung beetles use antlers and horns, respectively, to fight off other males during courtship.

These traits, which can vary widely within the same species, have long fascinated biology Professor Erin McCullough.

“Sexual selection, or competition over mates, is responsible for many of the biggest, flashiest, most colorful, and conspicuous traits that we find in the animal kingdom,” she says.

What’s puzzling, however, is that these traits can make species more susceptible to predators, seemingly at odds with natural selection.

“Reproduction is the currency that really matters,” says McCullough. “It doesn’t matter if an individual lives forever — or if it lives a whole lot longer than its peers — if it never succeeds in attracting a mate, because then it won’t leave any of its genes to the next generation.”

Challenge. Change. is produced by Andrew Hart and Melissa Hanson for Clark University. Listen and subscribe on Spotify or Apple Podcasts. Find other episodes wherever you listen to podcasts.

Evolutionary biologist Erin McCullough and student Syd Kochensparger ’25 examining samples collected at Clark's Hadwen Arboretum
Professor Erin McCullough (right) works in the lab with Syd Kochensparger ’25.
Close up samples of Onthophagus hecate, orpheus, and striatulus collected from Clark’s Hadwen Arboretum
Close up samples of Onthophagus hecate, orpheus, and striatulus collected from Clark’s Hadwen Arboretum.

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