Female treefrogs struggle to choose mate amid crowded calls, says new study

Female treefrogs typically favour mates with faster, more regular calls, but in a chorus with many calls, they may struggle to identify the best one. (Image: University of Tennessee)

Treefrogs are known for their loud, rhythmic mating calls. But in crowded environments, choosing the best mate may not be so simple. New research shows how complexity affects choices.

Why do female treefrogs find mate choice difficult?

An international study conducted by Assistant Professor Jessie Tanner from the University of Tennessee, Knoxville, discovered that female grey treefrogs like to choose males that call quickly and consistently. But when presented with four or eight varying calls, they made inconsistent choices. This indicates that dense areas, referred to as choruses, make it difficult for decision-making. In the wild, many males call at once, making it harder for females to pick the best mate.

“Females might not always get what they want,” said Tanner. The study shows unattractive males could still reproduce. These males benefit from crowded spaces, where discrimination becomes difficult. As a result, evolution may slow down more than previously expected.

How does choice overload affect animal behaviour?

The research investigates “choice overload”, where too many options hinder decisions. Just like humans struggle in supermarkets or dating apps, female tree frogs face similar challenges. Tanner explained that choice overload may explain why some unattractive males succeed.

Tanner’s study was published in Proceedings of the Royal Society B. She worked with scientists from Colorado State University, the University of Minnesota, and Tel Aviv University. The findings provide a new perspective on how mate choice influences evolution.

What’s next in understanding animal decision-making?

Tanner and Assistant Professor Claire Hemingway study choice overload in animals at UT’s Collaborative for Animal Behaviour (CoLAB). They explore whether this phenomenon occurs in bumblebees and wood roaches too. Understanding if choice overload is species-specific or widespread remains a key question.

The research began when Tanner studied how noise affects cricket mate choice. It became clear that both noise and choice overload contribute to decision difficulties. Now, her team aims to separate these factors.

This study helps explain how crowded environments shape evolution. It demonstrates how, not only treefrogs, but potentially all animals are affected by complexity.