To achieve this, animals use "sexual signals." These conspicuous displays or ornaments help beat out the competition in the contest for mates. And some of the most beautiful aspects of the animal world have evolved for this purpose.

Sexual signals are costly, though, and not just in terms of the energy it takes to sing or dance. One seemingly obvious and profound cost is predation. The idea is simple. Just as your private phone call may be overheard by nosy passersby, so too may the bright colors and loud calls of sexual displays catch the eyes and ears of predators seeking a meal.

From the shimmering wings of butterflies, to the sweet songs of birds, we admire these signals in other species daily—even though they're not meant for us. So how often are they intercepted by predators? And is the risk equal across all kinds of signals?

My colleagues and I sought to answer these questions in a recent publication. We found the dangers to signalers are real, although much more varied than we once thought.

Eavesdropping on private conversations

Biologists describe the illicit interception of sexual signals as "eavesdropping," and it has been formally studied since at least Charles Darwin. The Tungara frogs of Central and South America are a classic example; their loud mating calls attract the unwanted attention of parasitic flies in search of a blood meal.