PUBLISHED RESEARCH: George Mason biologist helps uncover how transition to a fruit-based diet drove the evolution of colorful bird courtship displays
George Mason University Department of Biology Associate Professor Haw Chuan Lim contributed to an international study exploring how a fruit-rich diet may have helped lay the evolutionary groundwork for manakins’ vibrant feathers and elaborate courtship behavior.
Male manakins, part of a large lineage of tropical birds called subsocines, are known for their brilliant feathers, rapid movements, and distinctive sounds produced during elaborate courtship performances. New research suggests the evolutionary foundation for these spectacular sexually selected traits may have begun with something much simpler: the birds’ ability to taste sugar and consume chemically defended fruits.
Lim is a co-author of “Genomic and physiological changes in a sexually selected and frugivorous bird radiation,” published in Current Biology. The international team combined genomic comparisons, laboratory experiments, and evolutionary reconstructions to examine how fruit-eating influenced the diversification of manakins. Their analysis suggests that key adaptations for eating fruit evolved before the development of the birds’ colorful plumage and complex courtship displays.
The study focused on five manakin species and, by comparing their genomes with those of related birds, identified evolutionary changes in genes associated with taste perception, digestive enzymes, and other biological functions involved in consuming fruit.
According to the study, most birds lost the taste receptors typically used to detect sweetness during their evolutionary history. Researchers found that manakins instead repurposed a receptor normally associated with savory, or umami, tastes to recognize sugars. They also identified changes in a digestive enzyme that may allow manakins to eat a wider variety of fruit, including fruit that is unripe or protected by natural chemicals. Together, these adaptations may have helped manakins access a reliable and abundant food resource.
“We are only beginning to uncover what the omics revolution can reveal about the diversification and complex interactions that shape life,” said Lim. “At a time of unprecedented global change, with so much still unknown, especially in the tropics, omics tools and related advances, such as artificial intelligence, will be essential for understanding the evolutionary and ecological processes that generate biological diversity.”
The manakin study offers one example of how genomic tools can reveal the sequence of evolutionary changes that shape biodiversity.
When the team reconstructed the evolutionary timeline of these genetic and functional changes, it found evidence that fruit-related adaptations emerged first. Access to a reliable, nutrient-rich food source may have reduced the time and energy required for foraging, creating an energetic foundation for the evolution of costly courtship behaviors. Over time, sexual selection likely favored increasingly colorful feathers, complex displays, and elaborate ornaments.
The findings show how changes in diet and physiology can influence behavior and mating systems, providing new insight into how ecology, physiology, and sexual selection interact to shape biodiversity.
The study also reflects the broader focus of Lim’s research. His lab uses genomic and other approaches to study evolution across a range of spatial and temporal scales, including how geography and geological history shape bird diversification, the genomic processes underlying speciation and gene flow, conservation genetics in fragmented forests, and the role of animal-associated microbes in functions such as pathogen defense and digestion.
The findings suggest that adaptations for finding and digesting fruit may have helped create the evolutionary foundation for some of the most elaborate courtship behaviors seen in birds today. More broadly, the research demonstrates how diet, physiology, behavior, and reproduction can interact to shape biodiversity.
